In what is perhaps the most 2020 of coffee brew science news, the SCA has just announced their recently published study stating that, who cares, use whatever water temperature you want, nothing matters. Hot brew, cold brew, medium brew, whatever's clever, Goldilocks. Ok, so that may not be exactly what they said, but it’s pretty close.
Published Monday, October 5th in Scientific Reports, Brew temperature, at fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee is part of a three-year research project undertaken by the UC Davis Coffee Center and supported by the SCA’s Coffee Science Foundation and the Breville Corporation with the aim of achieving a “deeper understanding of brewing fundamentals,” per an SCA press release.
For the study, two coffees were brewed at three separate temperatures—87°C (188°F), 90°C (194°F), and 93°C (199°F)—to be served to a panel of expert tasters. Each coffee was brewed to a specific total dissolved solids (TDS) value and percentage extraction (PE), with the grind size and total brew time being adjusted to hit these marks. When the TDS and PE were the same across all temperature variants of the three brews, the “tasters were unable to differentiate between them.”
By contrast, when the TDS and/or PE were different, the tasters could much more easily distinguish the brews. This, according to the study, suggests that TDS and PE—the former more so than the latter—have the greatest impact on the sensory properties of a given coffee. Per Prof. William Ristenpart, co-author of the study:
If [TDS and PE] are the same in two different brews, it doesn’t matter what brew temperatures were used to achieve them because tasters can’t differentiate them: they taste the same. In other words, it’s the destination that matters, not the route you took to get there.
In short, water brewing temperature (and grind size and brew time) don’t matter, do what you want, who cares… so long as you adjust the other two factors to achieve the desired TDS. You do you. We are all but space dust, ground to a specific micron size, saturated by an ever-changing river of chaos, to temporarily take the shape of our given vessel before returning to that which we came.