What temperature do you like your coffee to be? It changes from person to person, and that can make it somewhat difficult for cafes to decide how hot to serve their brews. But now, a new study by researchers from the UC Davis Coffee Center examines coffee temperature as it relates to customer acceptance, and it has nothing to do with flavor perception.
Published November 30th in Nature, researchers William D. Ristenpart, Andrew R. Cotter, and Jean-Xavier Guinard sought out to see what, if any, coffee drinking temperature had the greatest mass acceptance. To do this, they asked 118 participants to each taste 27 different coffee samples—giving them a total of 3,186 data points. For each coffee participants were asked to rate the enjoyability of the temperature on a five-point Just About Right (JAR) scale, where they had to select between Much Too Cold, Somewhat Too Cold, Just About Right, Somewhat Too Hot, and Much Too Hot.
For the purposes of the test, researchers were looking for the coldest temperature that had the greatest percentage of participants rating it as Just About Right or Somewhat Too Hot. Their reasoning for this is the general one-way nature of coffee’s drinkable temperatures. If a coffee is too hot, a person can simply wait a minute or two to let it cool. Whereas once a coffee has cooled beyond the ideal, consumers have less recourse to correct it. Thus, slightly overshooting the perfect temp on the hot side is preferred.
They found that, while tasting temperatures 60-62°C (140-144°F) and 62-64°C (144-147°F ) had the largest percentage of participants stating that they were Just About Right with 65% (with 56-58°C (133-136°F) and 58-60°C (136-140°F) trailing just behind with 64%), because a significant enough portion rated them as Somewhat Too Cold—between 4% and 12%—a higher temperature may better serve a larger swath. This range ended up being 68-70°C (154-158°F), which only had 51% finding it Just About Right, but another 39% rating it as Somewhat Too Hot, and most importantly, only 1% finding it Somewhat Too Cold. Any higher, in the 70-72°C (158-162°F) range, and the Just About Right dips well below half, to 40%, making it less than ideal even with a 0% Somewhat Too Cold response rate.
Researchers noted that temperature had little effect on the perceived adequacy of flavor intensity, mouthfeel, and acidity, each of which had a far greater impact on participants’’ assessments of a coffee’s quality. Temperature did, however, appear to have a slight effect on a customer’s intent to purchase, with the data showing a slightly increasing trend as coffee went from 56°C to 64°C, with a small decrease appearing at the temperature go above that point, then making a larger drop-off at 71°C.
Researchers are quick to point out that their study is focused specifically on drinking temperature, and the brewing temperature will actually vary based on the environment but will nonetheless be quite a bit higher. There are a lot of steps between heating the water to brew with and a customer tasting it, and they all contribute to temperature loss. But according to the study, that goal temp, in order to appease the largest percentage of the population, should be 68-70°C.