If you want to brew smooth, great-tasting coffee every single time, there’s two things you need to do. With the water, I mean. First is to get the temperature right.
A good starting temperature is between 195°F (91°C) and 202°F (94°C). Read a little lower to see the sources I got that range from. Along with the second important thing you must do with your water when making coffee. And also how to tell in two seconds if you’re getting the temperature of your water wrong.
How Hot Should Water Be for Coffee?
Here are three reputable sources on the ideal temperature of coffee. All three agree that the right temperature for coffee is around the 200°F or the 93°C mark. So try to aim for that when you’re brewing your coffee.
Here’s something important to bear in mind: your water will cool down as it brews. Therefore, go a little bit higher on the temperature for longer brew times.
For example, when I use 200°F / 93°C temperature water with my French Press, after three minutes the temperature inside has dropped to about 180°F / 82°C. If you’re wondering, I use an external thermometer to check that.
(By the way, I know the Celsius values are a bit janky. Not my fault. I’m just copying the data from each of the sources.)
How to get the right temperature of water (consistently!)
Option #1: Use a thermometer kettle
A thermometer kettle will heat the water to the exact temperature you choose. This gives you ultimate control over this part of the brew, and is therefore the best option if you want to get the perfect temperature water each time you brew.
I do own one, and yes it is an absolute dream. (And a nightmare when I have to brew without it). You fill the kettle with water then place it on the base which is plugged into the wall. Click the button to say what temperature you want, then watch the numbers on the little display go up.
The downside? They cost a pretty penny. You’re looking at up to a $100 investment to get one of these.
Option #2: Use water straight off the boil
The simplest and cheapest option is to use water that is straight off the boil. When I do this, I wait 5-10 seconds to let the steam and agitation disappear. This gives me a temperature of about 201-202°F (93-94°C) water which is almost exactly what you want. That’s measuring with an external thermometer, by the way.
The best part? It’s surprisingly consistent. If you’re fairly new to coffee, I’d say this is a perfectly acceptable way to get the right temperature of your water, time and again.
Option #3: Use an external thermometer
An external thermometer can tell you the precise temperature of your water, so you can use the correct temperature in your coffee. I use one that cost less than $10 from Amazon, and it works reasonably well.
The biggest problem with an external thermometer is they take a little time to adjust to the new temperature. Mine takes a few seconds, so you lose a bit of accuracy there. Maybe a more expensive one would work better.
What happens if your water to make coffee is too hot?
Hot water gives you less room for error, and can cause a wide range of unpleasant tastes in your coffee. These quotes tell you exactly what to expect.
…water that is too hot will also cause a loss of quality in the taste of the coffee.NCA
…temperatures above 202°F may result in sour-tasting coffee.Scott Rao in Everything but Espresso
Early work by Pangborn examined coffee brewed using a stirred pour-over technique with distilled water at 65, 80, 90, and 100 °C, and found that bitterness and sourness in general increased with temperature…
…hotter water predictably increased TDS and yielded more acrid, roasty, bitter, and sour attributes…Batali et al 2020
To help us explain, it will help to get science-y for a second. We measure the extraction of ground coffee in hot water in terms of Total Dissolved Solids (TDS) — sometimes called solubles — which are basically the coffee particles that get absorbed. Studies have shown an 18-22% TDS yield gives you the best tasting coffee.
A danger with very hot water overextracting. If you go above that 22% yield, the later-extracting bitter compounds dominate the taste. And also, because hot water requires a shorter brew time, it’s easy to underextract too. And going below a 18% TDS yield will mean the earlier-extracting acidic compounds dominate instead.
Is boiling water too hot for coffee?
Boiling water can be too hot for coffee, and will cause undesirable astringent tastes in your drink. However, the temperature needs to be above 205°F or 96°C. And that’s a good thing. Why?
Well, oiling water just doesn’t stay above this temperature for long in normal conditions. In my experience, I’ve found using boiling water fine for making coffee because by the time it hits your brewer or your cup, it has cooled down to 200°F or 93°C or less.
Does hotter water make stronger coffee?
Hotter water does make stronger coffee because it extracts faster. That means that the inherent coffee particles and solids dissolve into hot water faster than cooler water, so it will be more full-bodied and taste stronger. However…
If by “stronger” you simply mean more caffeine? Well, in that case, hotter water doesn’t make stronger coffee. This is because caffeine is extracted very quickly, almost all of it in the first seconds of the brew.
What happens if your water to make coffee is too cold?
Water that is too cold can result in coffee that is underextracted, and tastes weak, watery or sour. Here are some authority quotes on exactly why you shouldn’t use cool water.
Colder water will result in flat, under-extracted coffee…NCA
…temperatures below this range ‘may produce coffee that is bitter, astringent, acrid or too sharp’.Scott Rao in Everything but Espresso
It’s important to bear in mind that cold water on its own is not enough to cause these undesirable tests. Coffee can be brewed at almost any temperature, as you may know if you’ve ever tried brewing your own cold brew in the fridge for a day or two.
So the problem with using water that isn’t hot enough is not changing other variables to account for that. So if you use cool water, brew for a longer timer.
Sound easy? Well, dialing a coffee brew in is not easy. And if you do it wrong with cooler water you’re likely to either have weak and watery coffee, as it’s not extracting enough solubles. Or the other problem is undesirable sour or acidic flavors, which come from the organic acids that extract earlier on in the brew.
How hot should your water be to make coffee? (according to Breaking Bad)
Here’s a quick test for ya. What temperature do you think the boffins from Breaking Bad — y’know, the chemistry whizzes who make the best crystal meth the world has ever seen — brew their coffee at?
Seriously, have a guess.
This isn’t just a bizarre thought experiment, it’s a real scene from the show. And the best thing? You can see the full clip, along with the big reveal of the temperature they use, in just two minutes:
All of that just to say your water should be about 200°F. Bit excessive?
Either way, this article has hopefully given you a taste of what you need to do to make great coffee. Getting the right temperature is a good start. Really good, actually.
Beautiful-tasting coffee is all about getting the little things right. Do it consistently, and you’ll find you can make quality coffee. So good, you might give up the sugar, cream and milk! (Maybe…)
P.S. Here’s my review article on the best gooseneck kettles. You may want to check out the temperature one on there, great for getting the exact temperature you want.