Time to re-write that Brewers Cup competition routine. According to a new study, coffees brewed at different water temperatures are indistinguishable at the same extraction percentage and concentration. The paper, a collaboration between the Coffee Science Foundation and the UC Davis Coffee Center, was published in the academic journal Scientific Reports under the rather catchy title “Brew temperature, at fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee.”
Researchers at UC Davis used a Curtis C4 batch brewer to brew a washed Honduras at 87°, 90°, and 93° celsius. Other brewing parameters such as grind size and total contact time were adjusted to achieve the same extraction and strength with each brew. A trained panel of professional tasters were unable to significantly distinguish between the different brews.
On one hand, the findings should not be considered too surprising. As Professor William Ristenpart explains in this interview with Peter Giuliano, what matters is the finished result– not how it was achieved. A 20% extraction at 1.3% concentration is going to taste a certain way because what matters is what soluble compounds are dissolved.
Notably, SCA standards for water temperature during brewing are 92-96.° In fact, the ability to brew at these temperatures is a key feature of the SCA Certified Home Brewer program. Could you compensate for your Mr. Coffee’s lower brewing temperature with a finer grind? This study would suggest so!
But don’t let your water cool down too much! Hot water is a more efficient solvent, and most of us don’t have a fully programmable Curtis C4 to compensate for too cool water.
Personally, I would like to see the study expanded to include even more extreme temperatures. Cold brew, clearly, has a distinct flavor profile irrespective of extraction percentage or strength, which would suggest there is a temperature threshold that is significant for flavor– it might just be lower than once thought.