When making coffee the water temperature when brewing is one of the essential parameters. Use the wrong temperature and your coffee will be an odorless, insipid liquid, that barely qualify as drinkable. As a matter of fact the brewing temperature is just one of the factors that affect the perfect extraction. Coffee beans quality, grind size, brewing time, are also very important, and they are interdependent. The perfect temperature is only perfect if we consider a certain grind size and a certain extraction time. But we’ll show you in a bit how these are interconnected.
Some Coffee Chemistry
Coffee is an aqueous extract of several soluble solids and oils. As an aqueous extract, the chemistry of coffee extraction is the same as any other solution: we use a solvent, which is the water to obtain our solution – the coffee. There are a few parameters that affects dissolution time and the solution concentration. One of these parameters is the solvent temperature, (water). So if we boil our solvent with the solute in it the extraction will be done in seconds, right? Yes, but not in our case. Coffee is a combination of solutes that get dissolved at different temperatures. Some of these compounds are undesirable in our coffee, and we don’t want to extract them. This is how the smart people in the specialty coffee came up with the perfect number for coffee brewing temperature. Brew it too hot, and you’ll extract the bitterness in coffee, (it’s called over extraction). Brew it too cold and you’ll get a watery liquid that doesn’t have any taste or flavor. That’s only partially true, but we’ll get to it later in the article.
The Perfect Brewing Temperature
As I said before, the brewing temperature is directly determined by the other brewing factors: grind size and extraction time. There are a few more factors that play a role, for instance pressure, or agitation, (read stirring). These are specific to only certain brewing methods.
We are only discussing here the automatic drip coffee maker method, the most popular coffee brewing method. The specialty coffee authorities have established that the perfect brewing temperature for drip coffee is between 200° F ± 5°. Under 195° F coffee will turn up under-extracted, and will taste sour. This is because the acids in the beans are extracted at lower temperatures. Over 205° F coffee will be over-extracted and taste bitter. Sometimes will be astringent.
For the sake of precision, Specialty Coffee Association of America and the National Coffee Association recommend brewing coffee between 195 – 205° F. This actually includes hand drip method as well. Hand drip temperature can be tweaked, but this is the subject of another article. If you want to read the original recommendations of the two institutions you can read them here: SCAA brewing guide, and NCAUSA guide.
Espresso has a slightly lower brewing temperature, because pressure enhances the extraction. Manual brewing methods such as French press and AeroPress have also a lower brewing temperature because of the longer extration times. A lower temperature will eliminate much of the bitter compounds, that’s why French press and Aeropress are so great. In order to compensate for the low temperature brewing, we need to steep longer.
Coffee Brewing Temperature
Drip Coffee: 200° F ± 5°
Espresso: 195° F ± 5°
French Press: 195° F ± 10°
AeroPress: 180° F ± 5°
Coffee Makers – Do they Brew at the Right Temperature?
Not all coffee makers are equal. Some coffeemakers are simply too cheap to make a decent coffee. Some coffee makers are OK for a few months, and then they simply can’t provide the correct brewing temperature. Many coffee brewers though, don’t work right off the bat. They are poorly designed, and the heating element is off. Most of the times the heating element is underpowered because this extends the life of the resistor, reducing the production cost. Sometimes the water comes out too hot out of the heating element.
This is why you need to buy the more expensive stuff. If you want to make great coffee at home you can’t buy a cheap coffee maker. I am not the advocate of buying expensive stuff. As a matter of fact I am all for minimizing unnecessary expenses and useless gadgets. In some domains, however, you can’t get away with using cheap stuff. This is the case with specialty coffee.
A coffee maker has a couple of pieces that control the water temperature during brewing. A heating element, and the thermostat. Sometimes manufacturers use a thermocouple. The thermostat is the piece the regulates the heating element, and ensures a correct temperature. The problem with thermocouples is that they tend break if they are cheaply made. This tends to be the case with many brewers. The solution is to change the thermostat every few months, but not everybody is that handy, and changing a thermostat is a simple operation. Many manufacturers don’t even bother to offer the parts, so you’re stuck.
Good coffee makers that last you more than a few months are expensive. The safest route is to choose one of the SCAA approved coffee makers. There is only 12 of them at this time, and we reviewed some of them here.
What about the Drinking Coffee Temperature?
Drinking temperature of coffee is a personal preference, and common sense and personal taste are the only rules. I would note though, that very hot coffee cannot be properly tasted, since it will burn your tongue. Our taste buds get burned at very high temperature, and they cannot detect flavors properly. That’s why in the world of specialty coffee we should avoid burning beverages. There is nothing wrong with a piping hot joe, if that is your taste. A hot drink, however, will not allow you to enjoy all flavors in coffee.
Before we conclude this, there one more thing I’d like to touch about coffee temperature: the hot plate. From a specialty coffee perspective, the hot plate shouldn’t even exist. You brew what you drink. Keeping the coffee pot hot for hours is so wrong. After the first 20 minutes on the hot plate coffee doesn’t taste the same, and loses very much of its flavor and aroma. Please do yourself a favor, and don’t even care about the hot plate temperature. If you have to save the coffee for later, put it in a glass vacuum carafe. This way you maintain the temperature, and prevent the oxidation.