Slow juicers vs fast juicers
Read the marketing claims made by different juicers and you'll quickly end up confused. Slow juicers – also known as masticating or cold-press juicers – claim to extract more nutrients than their faster counterparts (known as centrifugal juicers), but they also tend to be pricier. Should you pay the extra, or are these supposed health benefits just empty claims?
We analysed the nutrient content of juices made in a range of popular centrifugal and masticating juicers, and scrutinised years of juicer test results to debunk common juicing myths.
If you're just looking to get the best juicer for your budget, head to our page to see the models that have aced our tough tests, extracting more and better quality juice than rivals, while also being easy to use and clean.
What's the difference between slow and fast juicing?
Slow juicers – also called masticating or cold press juicers. These use a slow-moving rotating screw or gears to gently crush fruit and vegetables against a perforated screen, pressing the juice out into your glass.
They are quiet to operate, great for preparing leafy greens, wheatgrass and soft fruits, and some types can also be used to make other foods such as pasta or grind coffee. But they tend to be expensive, tricky to clean, and, as the name suggests, slower to produce juice than centrifugal models. You'll usually need to chop fruit and veg into smaller pieces too.
Centrifugal (fast) juicers – these throw fruit and vegetables into a spinning sieve basket with sharp blades on the bottom. The combination of the blades and the spinning motion rapidly separates the juice from the pulp.
Not only are they quicker than masticating models, they tend to be cheaper and easier to clean, too. But they are often noisier, and not as good for juicing greens and soft fruits, such as berries.
Do slow juicers extract more juice?
Slow juicer manufacturers often claim that their products extract more juice from fruit and veg than centrifugal models. We put these claims to the test by rating every model for the quantity of juice they produce when we review juicers. We make three different types of juice – mixed fruit juice, pure orange juice and mixed vegetable juice – and then use the average quantity extracted across all three juices to come up with an overall rating.
Our verdict: In our tests, slow juicers do tend to consistently extract a decent quantity of juice. Every slow juicer we've tested gets either four or five stars (the maximum rating) for the quantity of juice extracted. But we've also found plenty of centrifugal juicers that extract optimum amounts of juice and achieve four or five star ratings, though there are a few models that score less well too.
Does slow juicing preserve more nutrients?
Despite what juicer manufacturers would have you believe, there is no simple answer to this, and the results vary depending on the juicer itself.
If you're looking to improve your intake of iron and vitamin C, you might want to consider a slow juicer. Iron helps to prevent blood anaemia, and vitamin C is great for strengthening the immune system. Our results indicate that some slow juicers do a better job of retaining these nutrients compared with centrifugal models.
But if you need more beta-carotene and potassium in your diet, you might be better off with a centrifugal juicer. Beta-carotene converts to vitamin A, which helps maintain healthy vision, while potassium is great for the heart and kidneys.
Neither slow nor fast juicers retain fibre well because the pulp of the ingredients is removed. keep the fibre in your drink, but how well they do they retain other nutrients? Check out our guide to to find out.
It's worth remembering that, while juicing can provide a quick and easy way of contributing to your five a day, no juicer will provide the same overall level of nutrients as eating fruit or vegetables.
Which? juicer nutrition testing
We tested 13 juicers, including seven slow juicers and eight centrifugal juicers. We selected popular, widely available models and some specialist models that made particular claims around nutritional extraction.
We used an identical recipe of fruit and vegetables in each machine and in every sample. Our aim was to see how well common nutrients such as vitamin C, beta-carotene, potassium, iron and fibre were retained by each machine.
To make sure no nutritional components escaped our clutches, we used two scientific techniques:
- Mass spectrometry – this separates nutritional components by mass. It works by converting a portion of our fruit and veg sample into ions, which are then fed through a mass analyser for us to detect.
- High pressure liquid chromatography (HPLC) – this separates nutritional components by solubility. The juice samples were put through a column of liquid at high pressure. Because each component reacts differently to this process, they separate, which means we can then measure how much of each is present.