Decaf beans that tell you how the caffeine came out

The best decaf coffee beans in the UK are Taylors of Harrogate Decaffé for value, a water-processed arabica blend sold as two 1kg bags, and Java Caffè Decaf Slow Roast if you want Swiss Water beans for a bean-to-cup machine. For espresso, Union's decaf is a dark speciality blend decaffeinated with water and carbon dioxide, and in our price data none of the three costs more per cup than the typical caffeinated kilo.

Which decaf coffee beans are best?

The ones that tell you how they were decaffeinated and still cost less per cup than most caffeinated beans. That rules out more of the market than you might expect: of the 13 decaf whole bean coffees with an Amazon listing in our catalogue, six say nothing specific about how the caffeine was removed. The three below do, and they cover three different methods and three different ways of drinking coffee.

Taylors of Harrogate Decaffé: best value

Taylors of Harrogate Decaffé is a 100% arabica blend of coffees grown in Central America and Brazil. Taylors says the decaffeination happens in Mexico, using what it calls the Pure Water Process: 'water enriched with natural coffee compounds draws out the caffeine', a step that is 'slow and has to be repeated again and again'. Taylors rates it 4 for roast and describes caramel and malt.

It cost around 31p a cup when we last checked, about half the 63p median for whole bean coffee. The catch is quantity. The Amazon listing is two 1kg bags, about 111 doses at 18g, which is nearly four months at one cup a day. Open one bag at a time and leave the other sealed. Independent write-ups are thin; the one that could be opened, Clarkey's Cafe in 2019, covers Taylors' Decaffé coffee bags rather than the beans, and describes cocoa notes and a 'rich mouthfeel'.

Skip it if you want a dark espresso decaf, or a single origin that tastes of one place.

Taylors also makes Hot Lava Java, the darkest roast in its range and one with robusta added for caffeine. The best strong coffee beans

Java Caffè Decaf Slow Roast: best for bean-to-cup

Java Caffè Decaf Slow Roast is 100% arabica, mainly from Central America, decaffeinated by the Swiss Water method and given what the roaster calls a full medium roast, by hand in small batches in Suffolk. The listing says it is 'ideal for use in traditional espresso and bean-to-cup machines' and works particularly well in cappuccinos. Medium roast matters in a bean-to-cup machine, where the manufacturers warn against oily beans.

It cost around 43p a cup when we last checked, 20p under the median. Nobody independent appears to have reviewed it, so the description here is the roaster's. If you want more weight for espresso, the same roaster's Java Caffè Dark And Decaf is also Swiss Water and rated 4.5 out of 5 for strength, at about 45p a cup; it is a dark roast, so check the beans for oil before they go in an automatic machine.

Why medium roasts suit an automatic machine's grinder, and how to keep a kilo fresh in one, is in the bean-to-cup shortlist. The best coffee beans for bean-to-cup machines

Union Decaf: best for espresso

Union's decaf kilo is sold on Amazon as Natural Process Decaf, described as 'indulgent, rich and full-bodied, with hints of dark caramel' and 'best brewed as an espresso'. It is a dark roast on the listing, speciality grade and 100% arabica. Union's own site is specific about the method: 'We only use water and carbon dioxide in our decaffeination process.' The origins in the blend change; Union's site currently lists Honduras and Peru.

It cost around 48p a cup when we last checked, and on Amazon it is the same price per kilo as Union Revelation, the caffeinated espresso blend. Skip it if you brew in a cafetière: Union's own listing points this coffee at espresso, and Taylors Decaffé costs less.

Union's caffeinated espresso kilo, at the same price per kilo, is reviewed in full. Union Revelation review

How do the three compare?

All three are 100% arabica and all three cost less per cup than the 63p whole bean median. The table uses each roaster's own description.

How is coffee decaffeinated?

By one of four methods, all applied to the green coffee before it is roasted. Two use only water, one uses carbon dioxide, and one uses ethyl acetate made from sugar cane.

Swiss Water soaks green coffee in what the company calls Green Coffee Extract, water already full of coffee's soluble compounds, so that only the caffeine moves out of the bean; carbon filters then strip the caffeine from the extract so it can be reused. Mountain Water is a Mexican water process that Descamex patented in 1987. The CO2 method was developed by Kurt Zosel at the Max Planck Institute: caffeine dissolves into the pressurised carbon dioxide, while most flavour compounds do not, and Wikipedia records that the largest plant, producing 10,000 tons of decaf a year, is Lavazza's in Italy. Two Chimps Coffee calls it the sparkling water or CO2 method: the green beans are moistened with water first, then liquid carbon dioxide draws the caffeine out.

Sugar cane decaf is ethyl acetate decaf. Descafecol in Colombia says its ethyl acetate comes from 'a sugar cane-based process' and is used with spring water, and points out that the compound occurs naturally in coffee cherries. Two Chimps, which buys only Swiss Water and sparkling water decafs, still groups ethyl acetate with the solvent methods. None of these sources offers evidence that one method tastes better than another.

Which decaffeination method does each roaster use?

Seven of these 13 decaf kilos name a method, and Union does it on its own site rather than the listing. The other six say nothing more specific than, at most, 'decaffeinated naturally'.

Grano Milano Decaf French Roast is the cheapest dark, robusta-backed decaf here, and the one with the least to say about how it was made. Grano Milano Decaf French Roast review

Does decaf coffee cost more than regular coffee?

Not in our data. The 76 whole bean coffees our catalogue flags as decaf have a median of 62p a cup, against 65p for the other 736. Among listings with an Amazon page the gap is wider: 42p across 14 decaf listings, counting multipacks separately, against 50p across 136 caffeinated ones. Where a premium does exist, it is a roaster's choice, and comparing a brand's decaf with its own caffeinated kilo shows it.

A 9p premium at one decaf a day comes to about £33 a year. The bigger cost for most decaf drinkers is waste. A kilo is 55 doses, so at one cup a day it lasts eight weeks, twice the four weeks from roasting that Union gives coffee at its best. Freeze half the bag on arrival, or buy a smaller one such as Lavazza Decaffeinated in 500g.

Is decaf coffee caffeine-free?

No, but a cup has very little. Wikipedia notes that US rules require at least 97% of the caffeine to be removed and Canadian rules set decaf coffee at under 0.1% caffeine, and it cites a 2006 study that found decaf drinks typically keep 1 to 2% of the original caffeine. In that study, 473ml cups of decaf held 8.6 to 13.9mg of caffeine; Wikipedia puts regular coffee at 95 to 200mg. illy states its decaf beans contain no more than 0.1% caffeine; Descafecol claims 99.9% caffeine-free for its sugar cane process.

Who should skip these three?

• Anyone who wants a dark, robusta-backed decaf espresso for the lowest price. Grano Milano Decaf French Roast is cheaper, at the cost of saying nothing about its method.
• Anyone who wants a decaf single origin. All three picks are blends.
• Anyone who drinks one decaf a day and will not freeze half a bag. A 500g or 250g bag, such as Lavazza Decaffeinated or illy Decaffeinated, will be used up while it is fresh.

The verdict

Buy Taylors of Harrogate Decaffé if you want a cheap, all-arabica decaf for a cafetière, filter or moka pot and do not mind two kilos. Buy Java Caffè Decaf Slow Roast for a bean-to-cup machine or for cappuccinos. Buy Union's decaf if you make espresso and want the same speciality kilo, for the same money, as Union's caffeinated blend.