Coffee machines: How we test coffee machines
Our taste extraction expert Giles Hilton
We've used over 5kg of coffee and 20 litres of water to make more than 700 measurements for Which? coffee machine tests.
Coffee machine expert taste testing
We asked Giles Hilton, head buyer for Whittards and a member of the Speciality Coffee Association, to act as our expert taster for all coffee machines we test.
Giles’s expertise means he can tell the difference between espressos produced by different machines using the same ground coffee, and how well the coffee machines we test extract the coffee.
During our blind tests he gives us his verdict on each machine’s espresso and cappuccino.
Taste is a big part of this test, but we also ask him to judge the appearance, including the all-important, crema, texture and espresso aroma.
Video - what makes a Best Buy coffee machine?
Giles talks about the quality of espresso from a Best Buy in our video.
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Noise
After feedback from Which? members, asking about the quietest coffee machines, and research from our coffee machine experts, we've now added a decibel noise assessment into our test programme, just like we do in our kettle reviews.
Maintenance
Coffee machines require a lot of love and attention to keep in top working order.
We found that a high percentage of coffee machine owners don't descale or regularly clean their coffee machine. Doing so could prevent blockages and leaks, so we now try to include any special maintenance instructions given by manufacturers when we test coffee machines.
Espresso volume
An espresso should be no more than 30ml – any more could result in a watery coffee.
We found some coffee machines continue to drip even when the flow of espresso is switched off.
Time to make an espresso
We time how long you have to wait for one 30ml espresso, then how long the machine continues to drip.
A good coffee machine will take up to 30 seconds to make 30ml of espresso and stop dripping.
Poor coffee machines can take more than 30 seconds to release 30ml and a further 30 seconds or more before they stop dripping completely, leaving you waiting longer for your drink.
Coffee temperature
To test the temperature of the coffee from the machines, we make an espresso then insert a digital thermometer into the centre of the cup.
We are looking for an average temperature no cooler than 60°C and no hotter than 88°C.
We use the cup warmers on machines that have them, but a warmed cup doesn't guarantee a hotter coffee.
Milk frothing
The basics behind any coffee are the same. A great espresso either on its own or combined with perfectly steamed milk.
So this is why we test how well coffee machines steam and froth milk.
Whether your favourite is a cappuccino, flat white or any of the coffee fads to hit the coffee shops, you'll be able to use our milk frothing rating to find how easy this is to achieve.
We time how long it takes before steam is produced from the steam pipe, how long it takes for the milk to be heated to 70°C, and how well the frothed milk combines with espresso, to make a cappuccino.
Total test score
Our total test score for coffee machines ignores price and is made up of the following factors.
Ground coffee and bean-to-cup machines
Taste test - 60%
Performance - 20%
Ease of use - 10%
Build quality - 5%
Portafilter - 5%
For ground coffee machines we give 5% of the total test score for the portafilter because on some machines, this can be really tricky to use.
Capsule coffee machines
Taste test - 60%
Performance - 25%
Ease of use - 10%
Build quality - 5%
Rewind our coffee machines live event
Which? experts were joined by top coffee connoisseur, Whittard's Giles Hilton, and Bob Payman, who's been selling and servicing machines for 15 years, for a live chat. We were kept busy with your questions on the best coffee makers and how to perfect your espresso making.
Missed it? Log in to replay the Q&A in full at Which.co.uk/coffeelive.
