Site icon Banjaran Foodie

Experiment: Effect of water temperature on the coffee cup

Water is about 90% of the coffee cup, so getting it right is essential to get a good cup of coffee. The temperature of the water can have a significant impact on how your coffee is extracted and what your coffee cup tastes like. Brewing coffee is simple science, you control the different parameters to get a good cup – temperature, weight, surface area (grind size), brewing time, etc. I have been playing and experimenting with coffee for a while, but temperature was a variable that I never paid as much attention to, until I did. And I definitely noticed the difference. This is when I invested in a simple baking thermometer to keep a track of the water temperature. The more variables I monitor, the better cup I get, and more consistent are the results. Good coffee brewing should be replicate-able, you should be able to make it again and again, so controlling variables is definitely important.

Why is brewing water temperature important?

The temperature of the water would influence the rate of extraction of your coffee. So, at what temperature you are brewing the coffee would determine what flavor compounds you are bringing out of the ground coffee into your coffee cup. As a thumb rule, the hotter the water, the quicker will be the extraction of coffee compounds like oils, acids, caffeine, etc. Now, each of these compounds impact the flavor of the coffee cup differently. If the water is too hot, your coffee will be over-extracted and unpleasantly bitter. If the water is not hot enough, your coffee would be under-extracted and unpleasantly sour with a very thin body. This is why getting the temperature right is important. At a lower temperature, the compounds like oils wouldn’t be extracted sufficiently, robbing the coffee of its body, its sweetness and other characteristic flavors.

What was my experiment?

I used the Vivaldi coffee by Saltoro Coffee Roasters, grown at the Stanmore Estate in Yercaud, Tamil Nadu. Vivladi is handcrafted to enliven the formal coffee textures grown from the remotest lands in India, balanced harmonically with rich fruity melodies to give the right upbeat kickstart to the day. It is a dynamic and versatile batch of beans that allows one to experience coffee the way they prefer – be it a French Press, an Aeropress, a Pour Over, anything, Vivaldi works beautifully with every brewing method. This is also the major reason I chose to experiment with this one as it has a beautiful range. It is a washed coffee containing the varietals SL795, Hawaiian Red Cuturra (HRC), and SLN 9. It is medium roasted with tasting notes of passion fruit, red currants, and peaches.

I brewed Vivaldi at two different temperatures – 90 degree Celsius and 84 degree Celsius. I took 15g of medium-coarse ground coffee (18 clicks on my Timemore C2 manual grinder, to be precise). I brewed it at a ratio of 1:15, so I took 225mL of water for the 15g of ground coffee. Brewing time averaged between 2:45 to 3:00 minutes.

Once I brewed both the coffees, I did a comparative tasting. Tasting them independently, I would never have been able to pick up the differences as minutely as I did with a comparative tasting. Comparative tasting has always helped me understand the differences and compare what I am feeling & tasting, something I cannot quite accomplish as successfully if I tasting just one cup.

What did I find in my experiment?

So, goes without saying the coffee brewed at 84 degrees was brighter than the one brewed at 90 degrees. It had a lot more vibrant acidity than the 90 degrees cup. It also had a bit lighter body, it felt lighter on the tongue. While the 90 degree cup felt more balanced, where all the flavors rounded off, no flavor overpowered anything else, and it felt like a good clear cup, the one at 84 degrees had an easily perceivable bright acidity, which in my opinion felt closer to a fruity, berry-like acidity. Not citrusy, not apples, more towards the currant-ish tartness. It wasn’t harsh, it wasn’t overpowering, it wasn’t undrinkable. It was nice and vibrant for me.

I like vibrant coffees, so I definitely did not find it unpleasant. But then I am someone who takes a whole lemon while cooking, squeezes half into the dish and half straight into my mouth, and who uses one full lemon to make a lemonade even when only half is essential. Hell, I even add double the lemon in my guacamole, so this is definitely a matter of personal preference. I definitely liked my 84 degrees cup, I do not find it unpleasant or unbearable in any way. It is still quite a few notches away from becoming unpalatable and unpleasant. However, this is my personal opinion and not a doctrine.

The 90 degrees coffee has a better body. I brewed both on a V60, so the body is usually less than what you would get in an immersion method like a French Press. But holding the coffee on my tongue, I can feel the 90 degree cup to have a better body, not a major difference, but perceptible enough for me. I like my coffees to have a good body, so on this factor, the 90 degrees cup scores higher for me.

I also found the 90 degree cup to be sweeter than the 84 degrees cup. This could likely be because of better extraction of the coffee flavor compounds at 90 degrees compared to 84 degrees. I feel the sweetness along with the brightness, and it all balances out in each sip.

The brew time for 84 degrees was slightly more than 90 degrees, very slightly, just about 10-ish seconds, so that isn’t a major difference, and I am not quite counting it. Its hardly enough to even call a difference, but I am still digging up more information on it.

Both coffees get brighter as they cool.

What is the ideal temperature for brewing?

According to the National Coffee Association (NCA), the ideal water temperature for getting the best coffee extraction is between 195°F and 205°F, i.e. 90.5 °C to 96.1 °C. Water so hot should be handled with extreme care, I did end up accidentally pouring the whole kettle full of water on me, and it burnt the skin like hell, I was in pain for days. NCA says this temperature range should work across all brewing methods – from French Press to Aeropress to Pour Over.

I would also suggest varying the temperatures a bit according to the roast of the coffee you are brewing. a Lighter roast can be brewed on the higher temperature side to speed up the extraction process (lighter roasts generally require longer brewing times). In contrast, darker roasted coffees can be brewed at somewhat lower temperatures to avoid over-extraction of the coffee and reduce the chances of getting an unpalatable dead bitter cup.

One very important thing – there is no rule here. Brew it the way you like it. You want to brew your coffee at lower temperatures, go on, do it. The important thing is to get a cup that you would like, that you would relish, that you can savor. If it is not what the rest of the people would like, it really doesn’t matter – your cup, your choice. So, go on, experiment and play around till you get what you like, and then keep replicating it.

So, should you invest in a thermometer?

From one home brewer to another – yes, please do. For a very long time, I was playing blind when it came to temperatures, and once I bought a thermometer, I realized what I was doing, how I could improve it, how I could tweak things a bit to get a different cup. It is helpful and it helps control an important parameter in the brewing game – the temperature. Simple thermometers like the baking thermometer I have should do the trick, no need for the fancy ones. So far as the thermometer is accurate enough and properly calibrated, we are good to go.

What temperature do you brew your coffee at? Tell me in the comments or find me on Instagram – @banjaranfoodie.

Exit mobile version