The myth that boiling water burns coffee grounds is so common that even the savviest coffee drinkers seem to accept it without question. However, when you consider that coffee beans are roasted at temperatures often exceeding 200 degrees Celcius, the idea that a dose of 100-degree water burns them is clearly not correct.
BEHIND THE BOILING WATER MYTH
Like most myths, this one has a reasonable explanation. Water temperature, both for brewing and drinking coffee, does affect the flavours, aromas and body of the drink. Most low-quality coffee is roasted really dark, which gives the beans a carbonic, burnt-like taste. Those "burnt" aromatics become more prominent at higher temperatures.
Boiling water also brings out different flavours in specialty coffee, notably its acidity, which can in fact be a benefit. Contrary to the myth, brewing a lighter roast specialty coffee with boiling water doesn't ruin it, and it certainly doesn't burn the beans.
THE IDEAL TEMPERATURE RANGE
The Specialty Coffee Association sets its standard water temperature for brewing at 92.2 to 94.4 degrees C, a range that’s widely accepted across the industry as ideal. Boiling water is clearly outside this temperature range. However, it’s important to understand that the ideal range is a recommendation and not a rule. It means that most people, drinking most types of coffee, find it tastes better when brewed within that temperature range. It does not mean that specialty coffees brewed with water in the 95- to 100-degree range are terrible. Some might even prefer a high-temperature brew.
IS WATER TEMPERATURE REALLY AN ISSUE?
The flavour and aroma differences caused by different water temperatures are noticeable, but subtle. If you’re having problems with unsatisfactory coffee, water temperature is an unlikely culprit. Most home coffee machines, whether drip- or capsule-style, are already set to brew within the ideal temperature range. If you use one of those machines, don't worry about water temperature.
If you use a French press or pour-over system, you do have full control over the water temperature. Experimenting with a thermometer and different brewing temperatures might be of interest, but it’s not necessary to be so precise in order to get a great cup of coffee. Start with quality coffee and you will probably find that even just-boiled water produces delicious results. Have no fear of burnt beans!