Years ago we reported how a McDonald’s customer sustained severe burns from scalding coffee from the takeout window at her local outlet. Because it turned out that this was a recurring issue with McDonalds the customer won a multimillion dollar lawsuit. Although boiling hot coffee can be dangerous and is not a good idea there are more reasons why you do not want overly hot coffee in your cup. So, when is coffee too hot?
How Hot Does Coffee Have to Be to Cause Burns?
Hot coffee spilled on exposed skin can cause burns at temperatures as low as 120 degrees Fahrenheit or forty-nine degrees Celsius. The severity of skin burns depends on temperature and time of skin exposure. The same temperatures apply to burning your mouth with too hot coffee. While it takes up to ten minutes to cause a severe burn at 120 degrees Fahrenheit it takes less than a second to cause a second or third degree burn at 150 degrees Fahrenheit or higher. A first degree burn causes skin redness. A second degree burn causes blistering. A third degree burn causes permanent skin or even nerve damage, secondary infection, and scaring. Thus, it is a good idea to be careful not to spill hot coffee on your skin or drink a scalding hot cup of coffee before letting it cool off.
What Does Excess Heat Do to Your Coffee?
If we assume that you are not going to drink scalding hot coffee or spill the same on yourself there are still issues with too hot coffee. If you brew your coffee at temperatures over 205 degrees Fahrenheit or 96 degrees Celsius, bitter compounds such as tannins and other plant material are extracted from the coffee grounds. You may end up with a chalky, dry, and bitter taste even with high quality Arabica coffee. Caffeine extraction is not affected by excess temperature. You will lose much of the high end aroma and taste from coffee’s aromatic compounds as well with brewing temperatures above the recommended range. And if you are reheating your coffee you can lose all of the remaining aromatic compounds and thus all of the remaining taste and aroma are lost by reheating at high temperatures.
What Temperature Is Best for Brewing Coffee?
For best results brew your coffee between 195 degrees and 205 degrees Fahrenheit or 90 to 96 degrees Celsius. You need to water to be hot enough to extract oils and flavor from your coffee grounds and not so hot as to extract bitter flavors. If your brewing temperature is too low you will get weak, sour or even salty taste.
Level of Coffee Roast and Brewing Temperature
To further refine your brewing temperature, use the higher end of the brewing range at 200 to 205 degrees Fahrenheit for a light roast to obtain the delicate flavors at this end of the roast spectrum. Brew at the lower end between 185 195 degrees Fahrenheit for dark roasts as dark roast grounds are easier to dissolve and provide their flavors.
How to Brew Coffee in the Right Temperature Range
The best way to brew in the ideal temperature range is to boil your water and, using a stem or digital kitchen thermometer measure temperature once you stop heating. Wait until the temperature comes to the top of your desired brewing range and then add water to your French press or pour the water over your grounds for pour over coffee. For these two methods four minutes is typically sufficient to accomplish the task at the correct temperature range.