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Cited by 42Coffee research and impactsSensory Analysis and Statistical MethodsFood Chemistry and Fat Analysis

Brew temperature, at fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee

Open access
Batali, Mackenzie E., Ristenpart, William D., Guinard, Jean-Xavier·2020·Scientific Reports
DOI 10.1038/s41598-020-73341-4PMC PMC7536440
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Abstract

The brew temperature is widely considered a key parameter affecting the final quality of coffee, with a temperature near 93 °C often described as optimal. In particular, drip brewers that do not achieve a minimum brew temperature of 92 °C within a prescribed time period fail their certification. There is little empirical evidence in terms of rigorous sensory descriptive analysis or consumer preference testing, however, to support any particular range of brew temperatures. In this study, we drip-brewed coffee to specific brew strengths, as measured by total dissolved solids (TDS), and extraction yields, as measured by percent extraction (PE), spanning the range of the classic Coffee Brewing Control Chart. Three separate brew temperatures of 87 °C, 90 °C, or 93 °C were tested, adjusting the grind size and overall brew time as necessary to achieve the target TDS and PE. Although the TDS and PE both significantly affected the sensory profile of the coffee, surprisingly the brew temperature had no appreciable impact. We conclude that brew temperature should be considered as only one of several parameters that affect the extraction dynamics, and that ultimately the sensory profile is governed by differences in TDS and PE rather than the brew temperature, at least over the range of temperatures tested.

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Written from the paper’s full text.

TL;DR

In drip-brewed coffee with TDS and PE held constant, brew water temperature (87, 90, 93 °C) had little effect on the trained-panel sensory profile, while TDS and PE significantly affected it. The authors conclude brew temperature is only one extraction parameter and sensory profile is governed mainly by TDS and PE over the tested range.

Key findings

  • MANOVA showed significant effects for TDS (F = 5.44, p < 0.001), PE (F = 2.46, p < 0.001), and TDS × PE (F = 1.56, p < 0.001), but not temperature (F = 1.25, p = 0.11) or temperature interactions up to three-way.
  • Univariate ANOVA found 17 of 31 attributes varied significantly by TDS, PE, temperature, and/or TDS × PE; only Nutty differed by temperature, by about 1 point on a 100-point scale, and temperature interactions were each less than 5 points.
  • PCA showed dimension 1 explained 72.2% of variance and dimension 2 explained 10.5%; TDS spread primarily across dimension 1, PE across dimension 2, with no clear temperature trend.
  • Response surface models showed 15 attributes with significant fits: Bitter, Astringent, Viscous, Rubber, and Earthy increased linearly with TDS; Sour, Citrus, Berry, Dark Green, Fermented, Brown Spice, and Smoky increased with TDS but decreased with PE; Sour had the largest change, a 20-point mean intensity difference between high TDS/low PE and low TDS/high PE; Black Tea decreased with TDS and increased with PE.

Methods

  • Same wet-washed Coffea arabica blend was drip-brewed on Curtis G4 brewers at 87, 90, or 93 °C, targeting nine TDS/PE positions across the Coffee Brewing Control Chart; grind size, brew ratio, and flow/duty cycle were adjusted to hold TDS and PE constant, yielding 270 total brews served at 65 ± 1 °C.
  • Twelve trained panellists (4 men, 8 women, ages 19–30) evaluated 31 sensory attributes in triplicate using generic descriptive analysis, blind randomized Williams Latin Square design, and 15-cm unstructured line scales.
  • Analyses included five-factor ANOVA with four-way interactions, pseudomixed ANOVA, MANOVA, Fisher’s LSD, PCA, and response surface methodology using measured TDS and PE.

Limitations

  • Stated: consumption temperature was controlled, so results may not apply if coffees brewed at different temperatures are served or consumed at different temperatures; coffee was served approximately 30 min post brew, which may allow flavour changes; only drip brewing with one commercial brewer and one Coffea arabica was tested; no chemical analysis was performed; TDS and PE were treated as independent variables although in practice they depend on many factors.
  • Stated/evident: only three brew temperatures (87–93 °C) were tested; the panel was small, young, and recruited from Davis, CA; the study was descriptive rather than hedonic, so it does not establish consumer preference or which chart region is “ideal.”
  • Evident: findings may not generalize to other brewing methods such as espresso or full-immersion/cold brew, or to other coffee species, varieties, or roast levels; proposed chemical mechanisms are hypotheses without chemical confirmation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41598-020-73341-4

Cites

49 of 49 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 60 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Brew temperature had no appreciable impact on the sensory profile of the coffee.

    “Although the TDS and PE both significantly affected the sensory profile of the coffee, surprisingly the brew temperature had no appreciable impact.”
    Quote in the paperSubstantial claim
  • Findingown data

    Five attributes (Sour, Berry, Citrus, Fermented, and Brown Roast) had significant differences based on both TDS and PE.

    “In contrast, eight attributes (Bitter, Astringent, Viscous, Dark Green, Rubber, Earthy, Ashy, Smoky, and Brown Spice) had significant differences based on TDS alone, one attribute (Black Tea) had significant differences based on PE alone, and five attributes (Sour, Berry, Citrus, Fermented, and Brown Roast) had signficant differences based on both TDS and PE.”
    Quote in the paperNot a substantial claim
  • Findingown data

    A highly prized attribute-black tea-was strongest at low TDS.

    “a highly prized attribute—black tea—was strongest at low TDS.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Eight attributes (Bitter, Astringent, Viscous, Dark Green, Rubber, Earthy, Ashy, Smoky, and Brown Spice) had significant differences based on TDS alone.

    “In contrast, eight attributes (Bitter, Astringent, Viscous, Dark Green, Rubber, Earthy, Ashy, Smoky, and Brown Spice) had significant differences based on TDS alone, one attribute (Black Tea) had significant differences based on PE alone, and five attributes (Sour, Berry, Citrus, Fermented, and Brown Roast) had signficant differences based on both TDS and PE.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Bitterness and several other attributes were found here to increase solely with TDS.

    “bitterness and several other attributes were found here to increase solely with TDS.”
    Quote in the paperSubstantial claim
  • May combine two claims. 36
  • Classified as probably not a substantial claim. 69

  • May combine two claims.

    Findingown data

    TDS and PE both significantly affected the sensory profile of the coffee.

    “Although the TDS and PE both significantly affected the sensory profile of the coffee, surprisingly the brew temperature had no appreciable impact.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Two sensory attributes, Brown Roast and Ashy flavours, both followed second-order fits that generally increased towards high TDS and high PE.

    “Two sensory attributes, Brown Roast and Ashy flavours, both followed second-order fits that generally increased towards high TDS and high PE.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There are almost no perceptible differences in the shape of the spider web plot for different brew temperatures, with only Nutty flavour yielding a slight but statistically significant shift with temperature.

    “Finally, there are almost no perceptible differences in the shape of the spider web plot for different brew temperatures (Fig. 4c), with only Nutty flavour yielding a slight but statistically significant shift with temperature.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingreasoning

    The brew-to-brew variability was slightly larger in higher PE brews, which generally required a longer brew time and may accordingly have had less consistency from varying amounts of channeling.

    “The brew-to-brew variability was slightly larger in higher PE brews, which generally required a longer brew time and may accordingly have had less consistency from varying amounts of channeling.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    One attribute (Black Tea) had significant differences based on PE alone.

    “In contrast, eight attributes (Bitter, Astringent, Viscous, Dark Green, Rubber, Earthy, Ashy, Smoky, and Brown Spice) had significant differences based on TDS alone, one attribute (Black Tea) had significant differences based on PE alone, and five attributes (Sour, Berry, Citrus, Fermented, and Brown Roast) had signficant differences based on both TDS and PE.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Brown Spice showed a Temperature × TDS interaction, and Earthy and Fermented showed a Temperature × TDS × PE three-way interaction.

    “Brown Spice showed a Temperature × TDS interaction, and Earthy and Fermented showed a Temperature × TDS × PE three-way interaction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The shape of the spider web plot shifts considerably for different TDS values, with the most pronounced changes for Bitter taste, Sour taste, and Astringent mouthfeel, and smaller but statistically significant shifts for 13 other attributes.

    “Note that the shape of the spider web plot shifts considerably for different TDS values (Fig. 4a), with the most pronounced changes for Bitter taste, Sour taste, and Astringent mouthfeel, and smaller but statistically significant shifts for 13 other attributes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Sour, Berry, and Fruity showed a significant TDS × PE interaction.

    “Several significant interactions were also seen in the univariate ANOVAs. Sour, Berry, and Fruity showed a significant TDS × PE interaction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The shape of the spider web plot shifts to a lesser extent for different PE values, with the largest differences observed for Sour, Black Tea, and Citrus.

    “The shape of the spider web plot shifts to a lesser extent for different PE values (Fig. 4b), with the largest differences observed for Sour, Black Tea, and Citrus.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Specific sensory attributes vary with brewing parameters, with brew total dissolved solids effecting more perceptible differences than percent extraction.

    “we report how specific sensory attributes vary with brewing parameters, with brew total dissolved solids effecting more perceptible differences than percent extraction.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: TDS and PE can be treated as independent variables for the purpose of this experimental study.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The coffee samples were evaluated blind and in triplicate by descriptive analysis with a group of trained sensory panellists to determine the intensities of 31 different sensory attributes.

    “The coffee samples were evaluated blind and in triplicate by descriptive analysis with a group of trained sensory panellists to determine the intensities of 31 different sensory attributes (listed in Table 1).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Batali et al. found that attributes like bitter, sour, and smoky were positively correlated with TDS, while attributes like sweet, fruity, and floral were negatively correlated with TDS.

    “Batali et al. examined the role of TDS via temporal fractionation of a drip brew, and found that attributes like bitter, sour, and smoky were positively correlated with TDS, while attributes like sweet, fruity, and floral were negatively correlated with TDS14.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Batali, M. E., Frost, S. C., Lebrilla, C. B., Ristenpart, W. D. & Guinard, J. Sensory and monosaccharide analysis of drip brew coffee fractions versus brewing time. J. Sci. Food Agric. 100, 2953–2962 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Coffee taste and flavour are made up of a complex mixture of carbohydrates, acids, lipids, proteins, antioxidants, and volatile aroma compounds.

    “Green and roasted coffee have been chemically characterized and we know that coffee taste and flavour are made up of a complex mixture of carbohydrates, acids, lipids, proteins, antioxidants, and volatile aroma compounds8, which can be manipulated at all steps, from origin, including the terroir of the coffee cherry, to the post-harvest processing method, the roasting, and the final brewing method”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [8] Clarke, R. J. & Macrae, R. Coffee : Volume 1: Chemistry. (Springer Netherlands, Dordrecht, 1985). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Brew temperature is widely considered a key parameter affecting the final quality of coffee, with a temperature near 93 °C often described as optimal.

    “The brew temperature is widely considered a key parameter affecting the final quality of coffee, with a temperature near 93 °C often described as optimal.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The Coffee Brewing Control Chart's central region spans TDS values of 1.15-1.35% and PE values of 18-22%, is denoted as "ideal", and is identified as the Specialty Coffee Association's "Golden Cup Standard".

    “The chart’s central region, which spans TDS values of 1.15–1.35% and PE values of 18–22%, is denoted as “ideal”, and is identified as the Specialty Coffee Association’s “Golden Cup Standard”5.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Coffee Standards. Specialty Coffee Association (accessed 22 Apr 2020). https://sca.coffee/research/coffee-standards (2018).

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Coffees served at higher temperature were reportedly perceived as more roasty and bitter than those served at lower temperatures, while most other attributes decreased in perceived intensity at higher serving temperatures.

    “Coffees served at higher temperature were reportedly perceived as more roasty and bitter than those served at lower temperatures, while most other attributes decreased in perceived intensity at higher serving temperatures29,30.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [29] Steen, I., Waehrens, S. S., Petersen, M. A., Münchow, M. & Bredie, W. L. P. Influence of serving temperature on flavour perception and release of Bourbon Caturra coffee. Food Chem. 219, 61–68 (2017). source

      Not checked in the free run.

    • cites [30] Chapko, M. J. & Seo, H. S. Characterizing product temperature-dependent sensory perception of brewed coffee beverages: Descriptive sensory analysis. Food Res. Int. 121, 612–621 (2019). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Lee et al. demonstrated that 50% of measured coffee components extract within the first quarter of brewing volume but that some flavour-active compounds extract more slowly, notably methyl cinnamate and indole.

    “Various studies have looked at the impact of brewing extraction time on sensory quality, with Lee et al. demonstrating that 50% of measured coffee components extract within the first quarter of brewing volume but that some flavour-active compounds extract more slowly, notably those like methyl cinnamate and indole that are less soluble in water than fast extractors like caffeine11.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Lee, T. A., Kempthorne, R. & Hardy, J. K. Compositional changes in brewed coffee as a function of brewing time. J. Food Sci. 57, 1417–1419 (1992). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Lower temperature coffee samples are generally rated less favourably by untrained consumers.

    “Lower temperature coffee samples are also generally rated less favourably by untrained consumers31,32.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [31] Pramudya, R. C. & Seo, H.-S. Influences of product temperature on emotional responses to, and sensory attributes of, coffee and green tea beverages. Front. Psychol. 8, 2264 (2018). source

      Not checked in the free run.

    • cites [32] Stokes, C. N., O’Sullivan, M. G. & Kerry, J. P. Assessment of black coffee temperature profiles consumed from paper-based cups and effect on affective and descriptive product sensory attributes. Int. J. Food Sci. Technol. 51, 2041–2048 (2016). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The Coffee Brewing Control Chart omits the wide variety of sensory attributes possible in coffee.

    “Perhaps most importantly, the chart omits the wide variety of sensory attributes possible in coffee.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [6] Sensory Lexicon. World Coffee Research (accessed 16 Jan 2020). https://worldcoffeeresearch.org/work/sensory-lexicon/ (2017).

      Not checked in the free run.

    • cites [7] Spencer, M., Sage, E., Velez, M. & Guinard, J.-X. Using single free sorting and multivariate exploratory methods to design a new Coffee Taster’s Flavor Wheel. J. Food Sci. 81, S2997–S3005 (2016). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Drip brewers that do not achieve a minimum brew temperature of 92 °C within a prescribed time period fail their certification.

    “In particular, drip brewers that do not achieve a minimum brew temperature of 92 °C within a prescribed time period fail their certification.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [16] SCA Certified Home Brewer Program. Specialty Coffee Association (2017).

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Understanding the impact of brew temperature could potentially reduce the energy consumption of the coffee industry if it is determined that the brewer standards are held to an unnecessarily high temperature.

    “Therefore, understanding the impact of brew temperature could potentially reduce the energy consumption of the coffee industry if it is determined that the brewer standards are held to an unnecessarily high temperature.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In the scientific literature, it is accepted that temperature impacts the solubility, volatility, and extraction kinetics of various coffee components.

    “In the scientific literature, it is accepted that temperature impacts the solubility, volatility, and extraction kinetics of various coffee components12,20, but there is only a small amount of existing scientific literature on the direct impact of brewing temperature on coffee sensory quality.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [12] Mestdagh, F., Davidek, T., Chaumonteuil, M., Folmer, B. & Blank, I. The kinetics of coffee aroma extraction. Food Res. Int. 63, 271–274 (2014). source

      Not checked in the free run.

    • cites [20] Cordoba, N., Fernandez-Alduenda, M., Moreno, F. L. & Ruiz, Y. Coffee extraction: A review of parameters and their influence on the physicochemical characteristics and flavour of coffee brews. Trends Food Sci. Technol. 96, 45–60 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Frost et al. characterized the impact of TDS and PE on sensory quality of drip brew for three different roast levels, and found generally more bitter and sour at higher TDS, and sweeter at lower TDS, regardless of roast level.

    “Most recently, Frost et al. characterized the impact of TDS and PE on sensory quality of drip brew for three different roast levels, and found similar trends—generally more bitter and sour at higher TDS, and sweeter at lower TDS, regardless of roast level15.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effects of brew strength and brew yield on the sensory quality of drip brewed coffee. J. Food Sci. 85, 2530–2543 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    The Coffee Brewing Control Chart is problematic from a modern sensory methodology perspective because it conflates hedonic or quality descriptors, measures of scale, and descriptive language.

    “Although widely used, the Coffee Brewing Control Chart is problematic from a modern sensory methodology perspective. It conflates hedonic or quality descriptors (“ideal”), measures of scale (“weak”, “strong”), and descriptive language (“bitter”).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Espresso, lungo, filter (drip) coffee, and French press have differing flavour intensities, with espresso type extractions being higher in roasty, fruity, bitter, and astringent attributes, whereas filter coffee and French press are sweeter; TDS and PE were not controlled.

    “Focusing on the latter, espresso, lungo, filter (drip) coffee, and French press, among others were found to have differing flavour intensities, with espresso type extractions being higher in roasty, fruity, bitter, and astringent attributes, whereas filter coffee and French press were found to be sweeter; TDS and PE were not controlled, however, and espresso type coffees are much stronger, with a”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Gloess, A. N. et al. Comparison of nine common coffee extraction methods: Instrumental and sensory analysis. Eur. Food Res. Technol. 236, 607–627 (2013). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Espressos prepared with sufficiently small temperature differences (80-93 °C) yielded imperceptible differences as assessed by triangle test performed by untrained panellists, while larger temperature differences (80-128 °C) yielded a significant number of panellists able to discern difference.

    “Further work on espresso determined that espressos prepared with sufficiently small temperature differences (80–93 °C) yielded imperceptible differences as assessed by triangle test performed by untrained panellists, while larger temperature differences (80–128 °C) yielded a significant number of panellists able to discern difference26.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] Klotz, J. A., Winkler, G. & Lachenmeier, D. W. Influence of the brewing temperature on the taste of espresso. Foods 9, 36 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Cold brew coffee prepared at temperatures less than 25 °C is widely reported to be sweeter and less acidic than hot brewed coffee.

    “At one extreme, cold brew coffee prepared at temperatures less than 25 °C is widely reported to be sweeter and less acidic than hot brewed coffee20–23, suggesting that less dramatic temperature differences might play a similar role for hot drip brew coffee.”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [20] Cordoba, N., Fernandez-Alduenda, M., Moreno, F. L. & Ruiz, Y. Coffee extraction: A review of parameters and their influence on the physicochemical characteristics and flavour of coffee brews. Trends Food Sci. Technol. 96, 45–60 (2020). source

      Not checked in the free run.

    • cites [21] Han, J.-W., Boo, H. & Chung, M.-S. Effects of extraction conditions on acrylamide/furan content, antioxidant activity, and sensory properties of cold brew coffee. Food Sci. Biotechnol. https://doi.org/10.1007/s10068-020-00747-1 (2020). source

      Not checked in the free run.

    • cites [22] Cordoba, N., Pataquiva, L., Osorio, C., Moreno, F. L. M. & Ruiz, R. Y. Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee. Sci. Rep. 9, 1–12 (2019). source

      Not checked in the free run.

    • cites [23] Rao, N. Z. & Fuller, M. Acidity and antioxidant activity of cold brew coffee. Sci. Rep. 8, 1–9 (2018). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Some differences were observed when espresso was prepared using a temperature gradient (ramping up or ramping down between 88 °C and 93 °C) compared to a fixed temperature (90 °C), with the "ramp up" gradient espressos evaluated more favourably by panellists than the espressos prepared with fixed or "ramp down" gradients in brewing temperature.

    “Some differences were also observed when espresso was prepared using a temperature gradient (ramping up or ramping down between 88 °C and 93 °C) compared to a fixed temperature (90 °C), with the “ramp up” gradient espressos evaluated more favourably by panellists than the espressos prepared with fixed or “ramp down” gradients in brewing temperature27.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Salamanca, C. A., Fiol, N., González, C., Saez, M. & Villaescusa, I. Extraction of espresso coffee by using gradient of temperature. Effect on physicochemical and sensorial characteristics of espresso. Food Chem. 214, 622–630 (2017). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    TDS and PE are linked via conservation of mass to the brew ratio of water to coffee grounds.

    “These quantities, which are linked via conservation of mass to the brew ratio of water to coffee grounds3, were combined by Lockhart in the classic “Coffee Brewing Control Chart” (Fig. 1).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Ristenpart, W. D. & Kuhl, T. The Design of Coffee: An Engineering Approach (Ristenpart/Kuhl Publishing, Davis, CA, 2017).

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The Specialty Coffee Association's Coffee Brewing Handbook states that a water extraction temperature of 92-96 °C is necessary for "proper extraction" (i.e., a TDS and PE within the "ideal range") to occur.

    “The Coffee Brewing Handbook published by the Specialty Coffee Association states that a water extraction temperature of 92–96 °C is necessary for “proper extraction” (i.e., a TDS and PE within the “ideal range”) to occur4.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4] Lingle, T. R. The Coffee Brewing Handbook: A Systematic Guide to Coffee Preparation (Specialty Coffee Association of America, Santa Ana, 2011).

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Pangborn found that bitterness and sourness in general increased with temperature for coffee brewed using a stirred pour-over technique with distilled water at 65, 80, 90, and 100 °C; complementary experiments with hard and soft water at 80 and 100 °C yielded similar increases.

    “Early work by Pangborn examined coffee brewed using a stirred pour-over technique with distilled water at 65, 80, 90, and 100 °C, and found that bitterness and sourness in general increased with temperature; complementary experiments with hard and soft water at 80 and 100 °C yielded similar increases24.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Pangborn, R. M. Influence of water composition, extraction procedures, and holding time and temperature on the quality of coffee beverages. Leb. Technol. 15, 161–168 (1982).

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    For certification, the Specialty Coffee Association requires that brewers reach 92 °C within the first minute of the brew, maintain at least that temperature for the remainder of the brew cycle, and never exceed 96 °C.

    “This standard has heavily influenced the home brewer market: for certification, the Specialty Coffee Association requires that brewers “…reach 92 °C within the first minute [of the brew], maintain at least that temperature for the remainder of the brew cycle, and never exceed 96 °C”16.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [16] SCA Certified Home Brewer Program. Specialty Coffee Association (2017).

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    All coffees were served at measured temperatures of 65 ± 1 °C.

    “All coffees were served at measured temperatures of 65 ± 1 °C.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    The grind size and flow rate were adjusted as needed to yield brews at the same TDS and PE when prepared with different water temperature, such that the TDS, PE, and brew temperature were all independent factors.

    “The grind size and flow rate were adjusted as needed to yield brews at the same TDS and PE when prepared with different water temperature, such that the TDS, PE, and brew temperature were all independent factors.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The drip brew basket geometry plays a role in the sensory properties of the coffee, with a flat-bottomed drip brew basket yielding a lower TDS and many different sensory properties than a semi-conical drip brew basket.

    “The drip brew basket geometry plays a role in the sensory properties of the coffee, with a flat-bottomed drip brew basket yielding a lower TDS and many different sensory properties than a semi-conical drip brew basket13.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effect of basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. J. Food Sci. 84, 2297–2312 (2019). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    An investigation of espresso coffee systematically varied the water temperature between 88 and 98 °C and found that hotter water predictably increased TDS and PE, and yielded more acrid, roasty, bitter, and sour attributes.

    “At hotter temperatures, closer to the traditional range of drip brew, an investigation of espresso coffee systematically varied the water temperature between 88 and 98 °C and found that hotter water predictably increased TDS and PE, and yielded more acrid, roasty, bitter, and sour attributes25.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] Andueza, S. et al. Influence of extraction temperature on the final quality of espresso coffee. J. Sci. Food Agric. 83, 240–248 (2003). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Mestdagh et al. investigated the kinetics of aroma extraction, showing a correlation between polarity of aroma compounds and extraction speed.

    “Mestdagh et al. investigated the kinetics of aroma extraction, showing a correlation between polarity of aroma compounds and extraction speed12.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12] Mestdagh, F., Davidek, T., Chaumonteuil, M., Folmer, B. & Blank, I. The kinetics of coffee aroma extraction. Food Res. Int. 63, 271–274 (2014). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Berry might also be a flavour that is associated with sourness, considering the sensory standard used in this study (unsweetened fresh mixed berries) is a product typically considered tart/sour and high in malic and citric acids.

    “Berry might also be a flavour that is associated with sourness, considering the sensory standard used in this study (unsweetened fresh mixed berries) is a product typically considered tart/sour and high in malic and citric acids43.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [43] Whiting, G. C. The non-volatile organic acids of some berry fruits. J. Sci. Food Agric. 9, 244–248 (1958). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    This behaviour was possibly due to black tea flavour being related to aromatic floral volatile compounds, which could potentially be linked to β-damascenone, a compound known for its floral aroma.

    “This behaviour was possibly due to black tea flavour being related to aromatic floral volatile compounds, which could potentially be linked to β-damascenone, a compound known for its floral aroma.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Some popular and valuable specialty coffee types, such as the Panamanian Geisha coffee, are associated with "flowery" and tea-like flavours.

    “some popular and valuable specialty coffee types, such as the Panamanian Geisha coffee, are associated with “flowery”47 and tea-like48 flavours”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [47] Vega, F. E. 2008. The Rise of Coffee (accessed 22 July 2020). https://www.americanscientist.org/article/the-rise-of-coffee.

      Not checked in the free run.

    • cites [48] Schering, B. Geisha Coffee: What to Know About 2018’s Award-Winning Coffee (accessed 22 July 2018). https://theculturetrip.com/central-america/panama/articles/geisha-coffee-know-2018s-award-winning-coffee/ (2018).

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    β-damascenone possibly increases in relative proportion to other flavour compounds during the longer brews associated with higher PE.

    “so it possibly increases in relative proportion to other flavour compounds during the longer brews associated with higher PE.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The decrease with PE is likely due to other attributes that continue to increase in intensity due to slower extraction times, such as bitter compounds that have the same concentration at a particular TDS regardless of percent extraction.

    “The decrease with PE is likely due to other attributes that continue to increase in intensity due to slower extraction times, such as bitter compounds that have the same concentration at a particular TDS regardless of percent extraction.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Our study was purely quantitative (i.e., sensory descriptive analysis rather than hedonic preference).

    “our study was purely quantitative (i.e., sensory descriptive analysis rather than hedonic preference)”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    This research only investigated drip brewing using a commercial brewer chosen for its versatile programmability.

    “this research only investigated drip brewing using a commercial brewer chosen for its versatile programmability.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    The term "Underdeveloped" likely reflects the increased sourness and associated flavours observed here.

    “The term “Underdeveloped,” likely reflects the increased sourness and associated flavours observed here”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The PE likely alters the relative ratio of bitter compounds to acids, and thus the perceived taste.

    “In other words, the PE likely alters the relative ratio of bitter compounds to acids, and thus the perceived taste.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Sourness in other studies has been shown to be easily suppressed.

    “sourness in other studies has been shown to be easily suppressed46”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [46] Green, B. G., Lim, J., Osterhoff, F., Blacher, K. & Nachtigal, D. Taste mixture interactions: Suppression, additivity, and the predominance of sweetness. Physiol. Behav. 101, 731–737 (2010). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Significant segments of coffee consumer populations are drawn towards bitter and astringent coffee.

    “other work has identified significant segments of coffee consumer populations are drawn towards bitter and astringent coffee49.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [49] Geel, L., Kinnear, M. & de Kock, H. L. Relating consumer preferences to sensory attributes of instant coffee. Food Qual. Prefer. 16, 237–244 (2005). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    In practice TDS and PE themselves depend on many factors in a complicated fashion.

    “in practice TDS and PE themselves depend on many factors in a complicated fashion (cf. Supplementary Table S1).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Supplementary Table S1

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    These patterns are possibly due to the relatively fast extraction of organic acids in coffee, which is high in acids such as acetic acid, quinic acid, malic acid, and others that are highly soluble and will rapidly extract into brewed coffee.

    “These patterns are possibly due to the relatively fast extraction of organic acids in coffee, which is high in acids such as acetic acid, quinic acid, malic acid, and others that are highly soluble and will rapidly extract into brewed coffee40,41.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [40] Ginz, M., Balzer, H. H., Bradbury, A. G. W. & Maier, H. G. Formation of aliphatic acids by carbohydrate degradation during roasting of coffee. Eur. Food Res. Technol. 211, 404–410 (2000). source

      Not checked in the free run.

    • cites [41] Balzer, H. H. Chemistry I: Non-volatile compounds. In Coffee: Recent Developments 18–32 (Wiley, Hoboken, 2008). https://doi.org/https://doi.org/10.1002/9780470690499.ch1b. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    Fermented could arguably reflect panellist perception of acetic acid, normally associated with vinegar (also a product of fermentation), and one found in high concentrations in kombucha, the chosen sensory standard for this study.

    “Fermented could arguably reflect panellist perception of acetic acid, normally associated with vinegar (also a product of fermentation), and one found in high concentrations in kombucha, the chosen sensory standard for this study42.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Jayabalan, R., Marimuthu, S. & Swaminathan, K. Changes in content of organic acids and tea polyphenols during kombucha tea fermentation. Food Chem. 102, 392–398 (2007). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationcitation

    The bottom third of the coffee brewing control chart ("Weak") might be more "ideal" for many consumers.

    “which might indicate that the bottom third of the coffee brewing control chart (“Weak”, cf. Fig. 1) might be more “ideal” for many consumers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    "Roasted" flavour is also a driver of liking.

    “the same study has indicated that “roasted” flavour is also a driver of liking”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effect of basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. J. Food Sci. 84, 2297–2312 (2019). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Bitter and Astringent are attributes potentially related to chlorogenic acids, as work has shown a correlation between these compounds and perceived bitterness and astringency.

    “Bitter and Astringent are attributes potentially related to chlorogenic acids, as work has shown a correlation between these compounds and perceived bitterness and astringency10”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Gloess, A. N. et al. Comparison of nine common coffee extraction methods: Instrumental and sensory analysis. Eur. Food Res. Technol. 236, 607–627 (2013). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationcitation

    The "ideal" box within the classic control chart is not necessarily ideal for everyone and accordingly might not be a useful descriptor for coffee brewing.

    “these observations suggest that the “ideal” box within the classic control chart is not necessarily ideal for everyone and accordingly might not be a useful descriptor for coffee brewing.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Several of these other attributes that follow the same pattern might be acid-associated flavours such as Citrus (citric acid).

    “Several of these other attributes that follow the same pattern might be acid-associated flavours such as Citrus (citric acid).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    These cross modal interactions between the taste and aroma components of flavour would serve to enhance both the Sour taste and the Fermented, Berry, and Citrus flavours, consistent with the observed pattern.

    “These cross modal interactions between the taste and aroma components of flavour would serve to enhance both the Sour taste and the Fermented, Berry, and Citrus flavours, consistent with the observed pattern44.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44] Spence, C. Multisensory flavor perception. Cell 161, 24–35 (2015). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous studies have identified attributes that are drivers of liking or disliking for consumers.

    “previous studies have identified attributes that are drivers of liking or disliking for consumers.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effect of basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. J. Food Sci. 84, 2297–2312 (2019). source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The chart implies that "Bitter" increases with PE.

    “the chart implies that “Bitter” increases with PE”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Fig. 1

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Viscous is an attribute that would be expected to scale linearly with TDS.

    “Viscous is an attribute that would be expected to scale linearly with TDS, as it refers only to the thickness and mouthfeel of the coffee, and a coffee with more dissolved solids should accordingly have a thicker mouthfeel.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Rubber and Earthy flavours are possibly related to sulphur containing compounds, such as thiopenes and thiazoles.

    “Rubber and Earthy flavours are possibly related to sulphur containing compounds, such as thiopenes and thiazoles38.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Tressl, R. Formation of flavor components in roasted coffee. In Thermal Generation of Aromas 285–301 (American Chemical Society, Washington, DC, 1989). https://doi.org/https://doi.org/10.1021/bk-1989-0409.ch027. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The extraction pattern of these flavours might be a contributor to the decrease in perception of sourness at a higher percent extraction, with these flavours at high PE masking the acidity of the high TDS coffees.

    “the extraction pattern of these flavours might be a contributor to the decrease in perception of sourness at a higher percent extraction, with these flavours at high PE masking the acidity of the high TDS coffees.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Odour-taste interactions have been investigated for other attributes in coffee.

    “odour-taste interactions have been investigated for other attributes in coffee45”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [45] Chiralertpong, A., Acree, T. E., Barnard, J. & Siebert, K. J. Taste-Odor integration in espresso coffee. Chemosens. Percept. 1, 147–152 (2008). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    A majority of consumers dislike bitterness and astringency in coffee products, whereas attributes like floral are positive drivers of liking.

    “Research from Frost et al. has indicated that a majority of consumers dislike bitterness and astringency in coffee products, whereas attributes like floral are positive drivers of liking13”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effect of basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. J. Food Sci. 84, 2297–2312 (2019). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    Because of variation in brew precision, two statistical analyses were performed: (M)anova treated TDS and PE as discrete factor levels, while Response Surface Methodology used measured TDS and PE instead of target TDS and PE, to ensure that conclusions were consistent using both methods.

    “Because of this variation in brew precision, two statistical analyses were performed: (M)anova treated TDS and PE as discrete factor levels, while Response Surface Methodology used measured TDS and PE instead of target TDS and PE, to ensure that conclusions were consistent using both methods.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    A generic descriptive analysis that combined elements of the Quantitative Descriptive Analysis and Spectrum methods previously demonstrated successful was utilized.

    “a generic descriptive analysis that combined elements of the Quantitative Descriptive Analysis and Spectrum methods previously demonstrated successful13,14,54 was utilized”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [13] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effect of basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. J. Food Sci. 84, 2297–2312 (2019). source

      Not checked in the free run.

    • cites [14] Batali, M. E., Frost, S. C., Lebrilla, C. B., Ristenpart, W. D. & Guinard, J. Sensory and monosaccharide analysis of drip brew coffee fractions versus brewing time. J. Sci. Food Agric. 100, 2953–2962 (2020). source

      Not checked in the free run.

    • cites [54] Lawless, H. T. & Heymann, H. Sensory Evaluation of Food Principles and Practices. (Springer, New York, 2010). https://doi.org/https://doi.org/10.1007/978-1-4419-6488-5. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Participants gave informed consent, had freedom to withdraw at any time, and were compensated for all hours.

    “participants gave informed consent, had freedom to withdraw at any time, and were compensated for all hours.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Coffee as a beverage has been removed from lists of substances believed to be carcinogenic due to chemical composition.

    “coffee as a beverage has been removed from lists of substances believed to be carcinogenic due to chemical composition51”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [51] OEHHA. Notice of Adoption—Section 25704 Exposures to Listed Chemicals in Coffee Posing No Significant Risk (accessed 4 Sept 2020). https://oehha.ca.gov/proposition-65/crnr/notice-adoption-section-25704-exposures-listed-chemicals-coffee-posing-no (2019).

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Participants were seated in isolated, positive-pressure, red-lit sensory booths.

    “Participants were seated in isolated, positive-pressure, red-lit sensory booths.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Calibration experiments with oven-drying of brewed coffee samples confirmed that the digital refractometer yielded accurate measures of the TDS.

    “Calibration experiments with oven-drying of brewed coffee samples confirmed that the digital refractometer yielded accurate measures of the TDS (see Frost et al.15 for details).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Frost, S. C., Ristenpart, W. D. & Guinard, J. Effects of brew strength and brew yield on the sensory quality of drip brewed coffee. J. Food Sci. 85, 2530–2543 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Samples were served in a blind randomized Williams Latin Square block design, with 3-digit blinding codes generated from Red Jade to prevent sample recognition and minimize sensory fatigue.

    “Samples were served in a blind randomized Williams Latin Square block design, with 3-digit blinding codes generated from Red Jade to prevent sample recognition and minimize sensory fatigue.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    F values were adjusted from the original ANOVA by performing a pseudomixed ANOVA to calculate new F ratios and determine which attributes were significant in spite of judge effect.

    “F values were adjusted from the original ANOVA by performing a pseudomixed ANOVA to calculate new F ratios and determine which attributes were significant in spite of judge effect55.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] Gay, C. Invitation to comment. Food Qual. Prefer. 9, 166 (1998). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The descriptive analysis took 14 sessions, over which all samples were blind tasted in triplicate.

    “The descriptive analysis took 14 sessions, over which all samples were blind tasted in triplicate.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    All work with human subjects performed here was reviewed and approved by the UC Davis Institutional Review Board (IRB# 1082568) and was performed in accordance with all relevant guidelines and regulations.

    “All work with human subjects performed here was reviewed and approved by the UC Davis Institutional Review Board (IRB# 1082568) and was performed in accordance with all relevant guidelines and regulations”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Fisher′s F statistic and lack of fit were evaluated to determine model fit, beginning with first order fit and then applying second order fit only where necessary.

    “Fisher′s F statistic and lack of fit were evaluated to determine model fit, beginning with first order fit and then applying second order fit only where necessary56.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [56] Box, G. E. & Draper, N. R. Empirical Model-Building and Response Surfaces (Wiley, Hoboken, 1989).

      Not checked in the free run.

75 of 75

  • The paper relies on this without support.

    No published work to date has examined the effect of brew temperature on the sensory qualities of drip brew coffee.

    “No published work to date has examined the effect of brew temperature on the sensory qualities of drip brew coffee.”

  • The paper relies on this without support.

    None of the sources specifying temperature ranges provide any data in support of the specified temperature ranges.

    “None of these sources, however, provide any data in support of the specified temperature ranges.”

  • The paper relies on this without support.

    To date no direct comparison of the effect of brew temperature at equivalent TDS and PE has been made and evaluated at controlled serving temperature.

    “Ultimately, temperature is believed to be highly relevant to coffee in terms of extraction, but to date no direct comparison of the effect of brew temperature at equivalent TDS and PE has been made and evaluated at controlled serving temperature.”

  • The paper relies on this without support.

    We are unaware of published data regarding changes in the sensory quality of brewed coffee held in vacuum insulated carafes over the scale of 30 min.

    “we are unaware of published data regarding changes in the sensory quality of brewed coffee held in vacuum insulated carafes over the scale of 30 min.”

  • The paper relies on this without support.

    There is little empirical evidence in terms of rigorous sensory descriptive analysis or consumer preference testing to support any particular range of brew temperatures.

    “There is little empirical evidence in terms of rigorous sensory descriptive analysis or consumer preference testing, however, to support any particular range of brew temperatures.”

  • The paper relies on this without support.

    A cup of coffee is approximately 99% water.

    “Since a cup of coffee is approximately 99% water”

  • The authors state this as an assumption.

    TDS and PE can be treated as independent variables for the purpose of this experimental study.

    “We treated TDS and PE as independent variables for the purpose of this experimental study”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Previous sensory analysis of full immersion coffee that examined the flavor profile of full immersion brews at fixed TDS found that the difference within the coffee sample was driven by roast level, origin, and then temperature.

    “Previous sensory analysis of full immersion coffee that examined the flavor profile of full immersion brews at fixed TDS found that the difference within the coffee sample was driven by roast level, origin, and then temperature4.”

    From Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time (2024) · cites this paper as [4]

    The Introduction and Materials and methods describe a sensory study of drip-brew coffee using the same roasted coffee, not full-immersion brews varying in roast level and origin. The Discussion (Implications for the coffee industry; page unavailable) says that full-immersion sensory comparisons need future investigation. The paper therefore does not report the claimed ranking of roast level, origin, and temperature. (LLM, conf=0.90)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • In hot drip brew coffees, bitterness and rubber flavor increase with both TDS and PE.

    “In hot drip brew coffees, bitterness and rubber flavor increase with both TDS and PE [13,16].”

    From Sensory Analysis of Full Immersion Coffee: Cold Brew Is More Floral, and Less Bitter, Sour, and Rubbery Than Hot Brew (2022) · cites this paper as [13]

    The Results (Response surface methodology) say bitterness and rubber flavor increased with TDS but had no statistically significant correlation with PE. The Discussion (Impact of total dissolved solids and percent extraction on sensory profile) reiterates that their apparent relationships with PE were not statistically significant, contrary to the claim that they increase with both. (LLM, conf=0.89)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • Most coffee sensory studies of brewed coffee focused on pressurized espresso brew or flow-based drip brew, while there are comparatively fewer sensory studies on full immersion brewing methods other than a few recent ones focused on cold brew.

    “While most coffee sensory studies of brewed coffee focused on pressurized espresso brew or flow-based drip brew2,4,6–10, there are comparatively less sensory studies on full immersion brewing methods other than a few recent ones focused on cold brew10–14.”

    From Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time (2024) · cites this paper as [4]

    The Introduction describes sensory work on drip and espresso coffee and cites recent cold-brew studies; this paper itself is a drip-brew sensory study. The Discussion calls for further investigation of full-immersion brewing. Neither section establishes that most brewed-coffee sensory studies concern espresso or drip brewing, or that full-immersion studies are comparatively fewer. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • The importance of TDS and E on sensory quality and consumer liking of coffee has been well established.

    “The importance of TDS and E on sensory quality and consumer liking of coffee has been well established1–5.”

    From Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time (2024) · cites this paper as [4]

    The Results (Response surface methodology; page unavailable) show that TDS and percent extraction are associated with changes in sensory attributes. But the Discussion (Implications for the coffee industry; page unavailable) says this study measured sensory attributes rather than consumer liking, and that relatively little data exist on consumer preferences for specific coffee flavours. The consumer-liking part is therefore not established by this source. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • The perception of sweetness probably is more related to the impression of sweetness and the absence or low level of other flavors such as bitterness and acidity rather than actual perceived sweetness.

    “Here, the perception of sweetness probably is more related to the impression of sweetness and the absence or low level of other flavors such as bitterness and acidity rather than actual perceived sweetness4–6.”

    From Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time (2024) · cites this paper as [4]

    The Introduction (page unavailable) reports that lower-strength brews were described as sweeter and less bitter and sour. But the paper does not say that this sweetness is an impression caused by low bitterness or acidity rather than perceived sweet taste; Table 1 treats Sweet as a taste attribute. (LLM, conf=0.76)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Nine attributes are described as eight

    Minor

    The statement says eight attributes differed based on TDS alone, but its parenthetical list names nine.

1 of 1

Cites

Flagged first, then by citations

1 of the 50 references couldn’t be matched to a known paper.

Research works printed but not linked: 4

  1. Lockhart, E. E. The Soluble Solids in Beverage Coffee as an Index to up Quality (Coffee Brewing Institute, New York, 1957).
  2. Ristenpart, W. D. & Kuhl, T. The Design of Coffee: An Engineering Approach (Ristenpart/Kuhl Publishing, Davis, CA, 2017).
  3. Lingle, T. R. The Coffee Brewing Handbook: A Systematic Guide to Coffee Preparation (Specialty Coffee Association of America, Santa Ana, 2011).
  4. Hair, J. F., Black, W. C., Babin, B. J. & Anderson, R. E. ANOVA and MANOVA. In Multivariate Data Analysis: A Global Perspective 439–500 (Pearson, London, 1998).

Cited by

Sorted by citations

Related

Authors
Batali, M. E., Ristenpart, W. D., & Guinard, J.-X.
Affiliations
University of California, Davis (US)
Corresponding author
Ristenpart, William D.
ORCID
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2020-10-05
Volume
10
Issue
1
Pages
16450-16450
ISSN
2045-2322 (ISSN-L)
DOI
10.1038/s41598-020-73341-4
PMC
PMC7536440
OpenAlex
W3089771434
Semantic Scholar
d89a950bb265bac563e4d826858f20edf53e1c03
Cited by
41
References
50
Citations by year
2026: 7 · 2025: 5 · 2024: 12 · 2023: 6 · 2022: 7 · 2021: 3 · 2020: 1
FWCI
2.55
Type
journal article
Language
en
Update notices
correction (2021-01-25)
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • eScholarship (California Digital Library) (submittedVersion)
  • eScholarship (California Digital Library) (submittedVersion, cc-by)
Funders
Specialty Coffee Association
Topics
  • Health Sciences › Medicine › Pharmacology › Coffee research and impacts
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Sensory Analysis and Statistical Methods
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Food Chemistry and Fat Analysis
Keywords
total dissolved solids, coffee brewing, descriptive sensory analysis, consumer preferences

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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