Coffee Brew Mini Series: Brewing Temperature Guideline

      One of the questions we hear a lot is "what's the right temperature for brewing coffee?" Depending who you ask, you'll hear an assortment of ranges cited as the "perfect brewing temperature." Before we get there, though, let's talk about why the right temperature is important.  

Why Temperature Is Important

  When you brew coffee, you're essentially causing a chemical reaction between the coffee grounds and the water. As the water runs through the grounds, it extracts various chemicals and compounds from them. In other articles, we've discussed why grind size and brew time are important to making good coffee. Temperature is the third variable. If the water is too cold, it doesn't extract enough of those flavor compounds to taste good. If it's too hot, it can "cook" those compounds, changing their chemical composition enough to make the coffee unpalatable.  

The Experts Say:

  According to the Specialty Coffee Association of America, the ultimate authority in all things coffee, the ideal brewing temperature for drip coffee is between 92 and 96 C. (approx. 198 to 204 F.) In order to earn the SCAA's certification, an automatic drip coffee brewer must reach 92 C within one minute, and remain between 92 and 96 throughout the brewing cycle. When it comes to coffee cupping, the SCAA is even more finicky. The water temperature, when poured on the coffee grounds, must be within 2 degrees of 200 F -- that is, between 198 and 202 F. And of course, those temperatures refer to brewing drip coffee. If you're making espresso, Illy -- whose name has been synonymous with espresso in Europe for decades -- places the perfect temperature range for espresso as 190-200 F. (88-93 C.). And if you're using the Aerobie Aeropress, the manufacturer recommends 175 F. as the ideal temperature for brewing. So, does all this mean that you need to take the temperature of your water before you start brewing? While we think it's kinda cool because we adore coffee geekery of all kinds, the definitive answer is not really. As long as you understand a few things and follow some general guidelines, you can be pretty certain of getting your water within the perfect coffee brewing temperature range.    

Getting to the Right Brewing Temperature

  The temperature that matters is the temp of the water when it hits the coffee grounds. A lot of cooling can happen between coming to a boil and soaking through your filter. The crew at Verve coffee did some experimenting with water temperature and coffee brewing. Among their discoveries: if you leave the water in the kettle -- with the cover on -- you can let it sit anywhere from 30 seconds to a minute and a half and still be within the right temperature range for brewing. If you pour it from the heating kettle into another vessel -- say a pouring kettle -- you can brew immediately because the very act of pouring from one kettle to another cools the water.  

• Bring your water to a boil. Remove it from the heat and let it sit for 30-90 seconds. The exact amount of time doesn't matter much there. As long as the water stays in the heating kettle, the temperature will only vary be a couple of degrees in that space of time.
• Alternatively, bring your water to a boil in an electric kettle, then pour it into a pouring kettle and brew immediately.

 

Staying in the Perfect Brewing Temp Zone

  It's also important that the temperature of the water stays in the temperature range throughout the brewing. Once you pour water into your coffee cone, coffee dripper or coffee pot, it will cool down a lot more rapidly. That's called "thermal loss." One of the best ways to avoid thermal loss is to preheat your brewing equipment by filling it with hot water or running hot water through it before you add coffee.  

• While your water is coming to a boil, rinse your coffee dripper with hot, hot water. If you're using an immersion brewer like a French press or a Solo, fill it with hot water and let it sit while your coffee brews.
• Rinse your coffee filter with hot water before filling it with coffee.
• If you're using an Eva Solo, zip her into her thermal sleeve.

 

Automatic Drip Brewers and Coffee Temps

  With most ADC brewers, you don't have a lot of control over the brewing temperature. Most consumer market coffee makers don't heat the water anywhere near that target temperature, and even fewer can maintain that temperature throughout the brewing process. The best way to be sure that your coffee is always brewed at the right temperature is to brew with an SCAA-certified brewer like the Bonavita or the Technivorm Moccamaster.  

Espresso Brewing Temperature

  Because espresso is a pressure-brewing method, it's especially sensitive to brewing temperature. A few degrees of difference can change the flavor in your cup appreciably. Most higher-end espresso machines allow you to monitor and manage the brewing temperature for your espresso machine through various mechanisms. Even on the lower end, there are ways to affect the brewing temperature, though temperature surfing can be a bit more complicated on a lower-end espresso machine. In general, lower temperature brewing emphasizes the bright, fruity acidity of the coffee. Higher temperatures extract more of the bitter roast flavors. Understanding that simple fact can help you adjust your brewing temperature to bring out the best in your coffee.  

What About Cold Brew?

  So, if heat is so important, what about cold brew coffee and Japanese ice drip coffee? Cold water will still extract soluble compounds from coffee grounds, but the extraction time will be far slower -- hours instead of minutes. In addition, cold brewing tends to leave behind bitter and very acidic flavor compounds, so the resulting brew is smooth and mellow. Needless to say, the usual rules about coffee brewing temperature don't apply.   Want to know more? Our next installment will talk about ways to troubleshoot your coffee brewing temperature and to make your coffee better than ever.