The ideal temperature for brewing coffee in a French press

When brewing coffee, an oft-repeated piece of traditional advice is to never use boiling water. Over the course of your coffee career, you've probably been told that boiling water somehow "burns" the coffee, or extracts a bad burnt flavor. Therefore, we recommend that the water temperature should be controlled between 90℃ and 96℃, and stipulate that the middle value of this range (92℃-94℃) should be used when cupping.

Of course, too high a temperature may extract bad flavors in coffee: higher-temperature water will extract less polar components in coffee, such as pyridine, which are associated with bitterness, astringency, roasted taste, and burnt taste. related. However, many coffee professionals now advocate using higher temperatures to brew coffee. This may be partly due to lighter roasts, improvements in coffee quality and roasting standards, but also because methods have been found to achieve higher, more even extractions, thus avoiding the "burnt taste" associated with over-extraction.

Conversely, lower temperatures tend to produce sour flavors due to under-extraction. While brewing at lower temperatures can reduce bitterness, a lack of bitterness in coffee often also indicates a lack of complexity.

The key temperature measurement for hand-brewed coffee is not the temperature of the water in the kettle, but the temperature of the ground coffee and water mixture (slurry). Because the hot water is added gradually to the cold coffee grounds, and the mixture is constantly losing heat to the air and filter, it is always significantly cooler than the brewing water in the kettle. This is sometimes cited as one of the limitations of pour-over coffee compared to batch brewing: the insulated environment and larger brew volume of a batch brewer means that the ground coffee water can be maintained at a higher temperature.

As we've already learned, the rate of heat loss from immersion brewing depends on the amount of brew (and the shape of the container). Another experiment in the immersion course showed that the choice of materials used in the French press can also have a big impact on the temperature of the brew and the results of the extraction. This means it’s impossible to come up with an “ideal” temperature that works for all baristas. Instead, your taste buds are your best guide.