How we test food processors
By Georgia Wilson
Which? puts every food processor through a rigorous series of tests to uncover the models that will make your life easier.
We've tested food processors from a variety of popular brands and our results have revealed that you don't need to blow your budget to get a fantastic machine - in fact, some affordable models are more effective than models that are ten times as expensive.
Our independent test results help you to be sure that the model you buy really lives up to its claims. Our reviews answer the most crucial questions about food processors:
- How well does the food processor chop, slice and grate?
- How well does it mix and knead?
- How well does it blend?
- Is the food processor noisy?
- How easy is it to set up and clean?
- Should I buy it?
Head straight to our food processor reviews to find the best model for you – or read on to learn more about how we test to answer each of these questions.
How well does the food processor chop, slice and grate?
We test each food processor with nuts, onions and flat-leaf parsley to see how well they can chop different types of food. A good food processor will consistently chop any ingredient - hard or soft - into fine, even pieces.
We slice different types of food, from soft to firm, to see how each food processor copes, and how long it takes. The slices are rated for evenness and uniformity, and particular attention is paid to how much food is left unsliced, how many slices are whole, and how many pieces have been broken or have large chunks missing from them.
Dubbed the ‘Double Gloucester test’, we check how fast and evenly each food processor grates cheese and carrots. Again, this tests how well it can grate both hard and softer foods - it can be challenging to handle both well. We deduct points if large chunks escape into the bowl, or remain on the blade, without being touched by the machine.
The image below shows real results from our tests from a good chopper, and a bad one. The nuts on the left are beautifully evenly chopped, while the ones on the right are uneven and have large unprocessed lumps.
How well does the food processor mix and knead?
We make cake batter in each food processor to test how good it is at mixing. We time how long it takes to mix and rate how evenly mixed the final result is. We also count the number of times the machine has to be stopped to scrape in unmixed ingredients from the sides. We also check how much the batter increases in volume after baking as this indicates how well the batter was mixed initially.
Food processors can take the hard work out of kneading - if they're good that is. A well-kneaded dough will rise properly, so we time how long it takes for dough to be kneaded and to rise, measure the increase in volume and rate the evenness of dough mixing. The dough is then baked to see if it has been kneaded well enough to rise properly. Finally, we check the consistency of the baked bread to see whether there are any large air holes.
How well does the food processor blend?
If the food processor comes with a blender attachment - be it a jug or a blending tool - we test it out. We time how quickly food can be puréed and how well it is blended. We look for a fine and even blend, so your smoothies and soups are tasty and lump-free.
Is the food processor noisy?
When you look at a food processor in a shop, you have no way of telling whether it can quietly take care of your kitchen tasks or if it makes a racket. We take into account motor noise, the sound of any vibrations while the food processor is working and any rattling of attachments.
How easy is the food processor to set up and clean?
Some food processors come with a confusing array of attachments or bowls that are tricky to fit and swap, or unnecessarily difficult to get clean. Which? members have told us that the ease of assembling food processors and cleaning the attachments and bowl are two of the most important considerations when buying a new model. To make sure you don't end up with a machine that's more hassle than it's worth, we check how easy it is to fit and swap attachments and whether it's easy to clean.
The test score that a food processor or mini chopper needs to earn to be named a Best Buy.
Should I buy it?
All of the tests above go into making the final overall score for each food processor we review. Because we know what's most important to you, some elements are more important than others, so carry different weights:
- 70% performance
- 25% ease of use
- 5% weight and storage
Only food processors and mini choppers that score 74% or above are awarded Which? Best Buy status.
Improvements to our tests
We're constantly improving our tests, so you can be sure that the food processors earning our Best Buy recommendation really are the best. In 2018, we updated our food processor tests. This means that models reviewed before 2018 have been tested slightly differently from more recent models, and aren't directly comparable.
However, you can still generally compare results for food processors tested before 2018 with those tested after, and each product's score still gives a good idea of how it will perform.
In addition to tweaks to existing tests, we now also record:
- information such as additional mixing attachments, running time and whether bowls are made of BPA-free plastic
- the maximum running time and maximum capacity of the bowls (as indicated by the max fill line, if there is one).
See all our food processor reviews to compare models and find the best for you.