How to avoid burning your coffee – and other hot drinks – by using a variable temperature kettle

Nothing starts the day off right quite like a perfectly brewed cup of coffee. If you’re lucky enough to own a fully-featured coffee machine, you’ll find yourself able to control factors like brew time, water temperature and grind size to create a perfectly tailored drink. However, if, like me, your coffee-making set-up comes with space and budget constraints, you might instead opt for a manual brewing option like a cafetiere, Aeropress or a pour-over device. 

These manual options can produce beautiful cups of coffee to match the best espresso machines, but they do require some finesse on the part of the user. Many manual brewing options have picked up bad reputations, due to people using freshly boiled water to make coffee. To avoid producing bitter, burnt-tasting coffee when making coffee manually, I recommend utilising a variable temperature kettle. 

My advice below shows you how to use a variable temperature kettle to brew the perfect cup of coffee, as well as other temperature-sensitive drinks like matcha and specialty teas.

How to brew coffee at the correct temperature

In this short guide section. I’ll explain why temperature matters in relation to making coffee, the temperatures I recommend for different types of coffee and give some tried-and-tested recommendations for anyone looking to pick up a variable temperature kettle.

Why does coffee brewed incorrectly taste bitter or burnt?

As noted above, people sometimes find coffee made in manual devices like cafetieres to have a bitter or burnt flavour. This isn’t, as you might guess, because the grounds themselves are burned by the boiling water but because higher temperatures can lead to over-extraction. Extraction refers to the drawing out of soluble compounds (for example, caffeine, sugars, oils) that occurs when coffee grounds come into contact with water. Under-extracted coffee will be weak and insipid while an over-extracted brew will taste acrid and sour. Many things can cause coffee to over-extract, an overly lengthy brew time, an incorrect ratio of grounds to water and, as we’re focusing on today, using water that is too hot.

What are the best temperatures to brew coffee at?

The only thing coffee enthusiasts enjoy more than a hot cup of coffee is arguing about how to make it. Ask five different experts their opinion on a topic like this and you’ll likely get five different but very fervent answers. My recommendation, generally, when it comes to all things coffee, is to use trial and error to produce the perfect cup for your palate. The only ‘perfect’ cup is the one that’s perfect to you. That said, there are some agreed upon temperatures ranges that coffee enthusiasts tend to prefer for specific types of coffee:

• For lighter roasts with more subtle flavours, you’ll generally want a high level of extraction to avoid your coffee tasting bland, so temperatures of between 95°C and 100° will be suitable.
• Medium roasts can be more variable, so depending on whether you’re using a medium-light or a medium-dark roast, a temperature somewhere between 85°C and 95°C will be the sweet spot.
  
• If you’re working with a dark roast, which can very easily over-extract and release some very strong, bitter notes, a temperature range as low as 80°C to 85°C will be your best bet.

Which variable temperature kettle should you pick?

While coffee enthusiasts may not always agree on exact methods and recipes, two things all aficionados value are consistency and replicability. Being able to note and compare the flavour differences produced by different coffees at different temperatures is part of the fun and satisfaction for many. Once you’ve settled on your perfect cup though, you’ll want to make it the same way every time.

To that end, a variable temperature kettle is the perfect way to ensure consistency and replicability for this part of the coffee-making process. Two of my favourite variable temp kettles for general use are the Russell Hobbs Attentiv (~£75) and the KitchenAid Artisan (~£195). The Attentiv is a clear-glass model with the ability to heat water anywhere between 40°C and 100°C, in five degree increments. The kettle is also a speedy boiler, has a 30 minute keep-warm function and is controlled via a slick LED panel on its base. The KitchenAid Artisan is a robust kettle, which can be set to temperatures between 50°C and 100°C, in ten degree increments. While it doesn’t offer the same level of precision as the Attentiv, I think the Artisan is still worth considering because of its beautiful design, which makes it both a pleasure to look at and to use.

How to make matcha using a variable temperature kettle

Matcha has exploded in popularity across the UK in recent years, with many large coffee chains now offering several different varieties of the drink. However, if coffee made at the wrong temperature can turn out a little unpleasant, matcha made with overly-heated water is a total disaster. Here’s how to do it right:

1. Add a half a tsp of matcha to a small mixing bowl or cup
2. Add a splash of water heated to 80°C, then whisk until fully incorporated and frothy
3. Once you’ve prepared your matcha shot, you can add it to your cup and then top it up with warm water to make matcha tea or heated milk to make a matcha latté

The best temperatures for preparing other speciality teas

If you’re interested in trying other speciality teas, here’s quick temperature guide that will help you extract the perfect flavour:

• Green tea: Brew at 75°C to 80°C for one to three minutes
• Oolong tea: Brew at 70°C to 95°C, depending on the firmness/looseness of the leaves, for three to four minutes
• Jasmine tea: Brew at 85°C for two minutes
• White tea: Brew at 75°C to 80°C for one to three minutes

If you like to brew loose-leaf tea, we recommend the Russell Hobbs Attentiv (~£75). Not only does its precise temperature selection make it perfect for a wide range of speciality teas, it also comes with a tea-steeping basket, allowing it to function as both a teapot and kettle at once.