Study Finds That Restaurants Serve Coffee Way Too Hot
Americans guzzle down roughly 400 million cups of coffee every day, and one of the top purveyors is McDonald's. The "Golden Arches" may be synonymous with burgers and happy meals, but many fans love the fast-food chain for its McCafé.
McDonald's policy is to serve its coffee at temperatures between 176–194 °F (80–90 °C), which is similar to other mainstream vendors. Whether this hinders or boosts McCafé's popularity is up for debate, but a recent review of the scientific literature published in the Journal of Food Science suggests that such a serving temperature is far hotter than what coffee drinkers prefer.
Researchers John Abraham of the University of St. Thomas in St. Paul and Kenneth Diller at the University of Texas-Austin performed an exhaustive search for all of the published studies which sought out the optimal temperature at which to drink coffee. They found six conducted in the past twenty years, collectively surveying nearly a thousand subjects. The studies' results are summarized below.
The studies' methods varied, but all found that people preferred drinking coffee that was between 135–162 °F, much lower than what coffee is typically served at.
"This fact demonstrates that service temperatures need not be at brewing temperatures," Abraham and Diller wrote. "Furthermore, when the added risk of injury is included in the decision, it adds further motivation for reducing temperatures."
In the past, lawsuits related to burn injuries from scalding coffee have been brought against Chick-Fil-A, Starbucks, Dunkin' Donuts, Wendy's, Burger King, and McDonald's. Most notably, in 1994, a civil jury awarded 79-year-old Stella Liebeck $2.86 million after she suffered third-degree burns from spilling McDonald's coffee on her lap. The payout was later reduced to $640,000. Documents drudged up during the trial revealed that McDonald's had previously received hundreds of reports of customers being burned by their coffee.
There's no reason to risk legal jeopardy or consumer safety, Abraham and Diller insist.
"Serving consumers beverages at very high temperatures is not only unnecessary (from a preference standpoint) but also unsafe... A more rational recommended range of service temperatures is 130 to 160 °F (55–71 °C)."
Coffee is typically brewed around 200 °F (93 °C) and served around 190 °F. Citing research, Abraham and Diller estimate that coffee could reach or be near their recommended temperature range if allowed to sit in a cup uncovered for roughly five minutes at room temperature. Alternatively, for faster service, cooled coffee could be mixed in with freshly brewed coffee. Sellers could also reduce the temperature at which they hold pre-made coffee.
Scalding coffee seems to be a fact of life, but there's no need for it.
Source: John Abraham & Kenneth Diller. "A Review of Hot Beverage Temperatures—Satisfying Consumer Preference and Safety." Concise Reviews & Hypotheses in Food Science. 11 July 2019.