What is Low-Caffeine Coffee? Meaning of Low Caffeine and Caffeine Content in Decaf Coffee

What Is Decaf Coffee?

Decaf coffee refers to beans that go through special processing before roasting to remove 96% to 98% of their caffeine. Every decaffeination method causes physical and chemical changes in the bean, and those changes inevitably affect its original flavor profile. Under EU rules, decaffeinated coffee is defined as coffee whose caffeine content does not exceed 0.1% of green bean weight. Starbucks' standard — which is also the general international benchmark — requires removal to below 3% of the original content, and coffee at that level may only be called low-caffeine coffee, not caffeine-free coffee.

Methods of Caffeine Removal

1. Direct/Indirect Solvent Method

The most common method today uses chemical solvents such as methylene chloride and ethyl acetate (EA) to dissolve the caffeine. Residual levels are extremely low and tightly regulated, yet many people still have concerns, believing methylene chloride to be a potential carcinogen and ethyl acetate capable of causing skin problems. Perhaps the caffeine left in decaf coffee will not be the main worry — the organic solvents will be.

2. Swiss Water Process

This is a patented method. Put simply, green beans are soaked in water, the resulting water is filtered through activated carbon to strip out the caffeine, and the filtered, supersaturated water is then used to soak the beans again.

3. Supercritical Carbon Dioxide (CO2) Method

The beans absorb water and expand, which loosens the caffeine molecules inside them. Carbon dioxide is then introduced under water pressure exceeding 100 atmospheres (atm), creating a high-pressure, low-temperature soda-water environment. Once captured by the carbon dioxide, the caffeine begins to migrate. Carbon dioxide is highly selective: it will not capture the carbohydrates and proteins in the beans, which are the main building blocks of coffee flavor and aroma.

Generally, Arabica beans contain about 1.3% caffeine, while Robusta beans contain 2 to 3 times as much. To produce decaf beans, most of today's technology relies on chemical solvents, water processing, or carbon dioxide. In practice, most beans still cannot be taken to zero caffeine; under EU rules the residue must stay at or below 0.1% of green bean weight.

Flavor Profile of Decaf Coffee

Compared with regular beans, decaf beans volatilize their aroma more easily because of the processing they undergo. If they are sealed poorly and oxidize, sweetness drops away and bitterness emerges, so decaf beans can move from relatively full-flavored to dull and lifeless in about a week.

The taste differs in other ways too. Because decaf beans must be processed before roasting, some of the caffeine that contributes to aromatic flavor is extracted along the way, and some drinkers find the cup weaker. Decaf also has a flavor profile of its own, with distinct layers of fragrance, smoothness, and subtle acidity. Indonesian and Kenyan coffees, for example, have completely different profiles, yet when properly roasted and fresh they are equally delicious. There are not many decaf origins to choose from, though — generally only Brazilian and Colombian varieties. Because they oxidize and spoil easily, decaf beans have a shorter shelf life than regular coffee and are best enjoyed within a week, whereas the optimal window for non-decaf coffee is one to three months from the roast date.

FrontStreet Coffee's Recommended Decaf Coffee Brewing Parameters

V60 / 90°C / 1:15 / two minutes

FrontStreet Coffee Recommendation

If you would rather lower your caffeine by choosing the bean than by buying a decaffeinated one, the first rule is simple: stay with Arabica, which carries roughly a third to a half of the caffeine found in Robusta. FrontStreet Coffee's Indonesian lots are a good place to start — the PWN Gold Mandheling is a wet-hulled Arabica, hand-sorted three times and roasted medium-dark, with herbal, spice, and woody notes and a fuller body and sweetness than most; it suits a moka pot, an espresso SOE, a pour-over, a drip bag, or an americano or latte. For something lighter, FrontStreet Coffee's Yunnan small-lot is a medium-roasted Arabica with soft nut and chocolate sweetness and a faint plum-like acidity, while the washed Yirgacheffe Gotiti cooperative coffee — an Ethiopian G1 lot roasted medium-light — brings white florals, citrus, orange, and green tea.

Keep in mind that decaf and low-caffeine beans shed their aroma faster than regular coffee, so drink them within a week of opening and press the air out of the bag between brews; brew them like any other light-to-medium lot — V60, 90°C, 1:15, about two minutes — and avoid leaving the ground coffee sitting open on the counter.