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If you’ve been interested in coffee for a while you have almost certainly heard a whole lot of different opinions on what temperature water you should use when brewing coffee.
In 2015, Australian Barista Champion Matt Perger caused a wave of controversy by recommending that people just use water straight off the boil to brew their pour-overs, contradicting the common thought at the time that water should be somewhere around 90º - 94º C (194º - 201º F). Meanwhile, the SCA asserts that water between 90º - 96º C is perfect for brewing coffee, while a new wave of baristas are recommending anything from 85º C and up!
So what’s the truth behind all the confusion, and is there really a “perfect” brewing temperature for brewing coffee? Today we’re going to explore just that! 👇
First I want to dismiss a common misconception about water temperature - specifically using water that’s too hot will “burn” the coffee. When coffee is roasted it reaches temperatures above 200º C, more than twice as hot as your boiling water! There is absolutely no way that using boiling hot water can burn your coffee.
Why use different brewing temperatures for coffee anyway?
The basic premise why you would want to use different water temperatures to brew your coffee is that water, a solvent (which dissolves and extracts minerals in coffee), is more efficient at higher temperatures.
Put simply: more heat = higher extraction
The idea is that you can tweak the temperature of your water to adjust how well it extracts and reacts with a specific coffee to get the desired flavour profile in the cup.
Modern Temperature Theory
While there are a lot of different opinions and theories about what is the “proper” temperature for brewing coffee, the modern theory (and what I personally resonate with) is that brewing temperature can be adjusted to bean density.
Following on from the premise that more heat in the water = better extraction, and remembering that denser coffee beans are harder to extract from than brittle coffee beans, then this theory seems to stand on some solid ground.
Hotter Water for Hard Beans
So what exactly are hard beans? Examples of beans that tend to be higher in density are:
• Washed coffees
• Coffees grown at high altitudes
• Light-roasted coffees
These coffees are dense, therefore it requires more energy to extract flavours from them. You can use a higher water temperature when brewing for these kinds of coffees.
Cooler Water for Soft Beans
What are soft beans? Well, here are examples:
• Natural, or other fermented processed coffees
• Darker Roasted Coffees
• Lower altitude coffees
These coffees are more brittle and soft and therefore are easier to extract flavour from. Try experimenting with lower-temperature water (around 90ºC) and taste the difference!
For an excellent guide on matching water temperature to process check out this graph from coffee pros Simon Gautherin and Pull and Pour Coffee!
Back to Reality
While it’s easy to descend into madness trying to line up all the variables perfectly, the reality is that brewing coffee is inherently random and it’s impossible to control everything.
A HUGE factor that is completely ignored in discussions about water temperature and coffee brewing is the temperature and material of the brewer itself. A metal brewer will hold and draw away heat differently than a ceramic or plastic brewer. So while your kettle might read 96ºC - once it’s poured over the coffee the water temp could be as low as 80ºC. (I suspect this is why Mr. Perger suggested water straight off the boil as a rule, since the water will drop temperature significantly as soon as it touches the brewer).
I will always recommend that people put their focus on the variables that have the biggest impact on brewing - grind size, total brew time, and water quality. However, if you have a solid brew recipe that works, and you’re still struggling to nail the brew - then go ahead and play with brew temperature, you might be surprised how a coffee can open up!
-P.T.
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