What is decaffeinated coffee?

Decaffeinated coffee is coffee from which most of the caffeine has been removed before roasting. Regulatory standards in most markets require that at least 97% of the caffeine be removed for a coffee to be labelled decaffeinated - in the EU the threshold is 99.9% for soluble coffee and 99.7% for roasted beans.

Decaffeination always happens to green coffee before roasting. The main commercial methods are: Swiss Water Process (water and activated charcoal filtration, chemical-free), Mountain Water Process (similar to Swiss Water, processed in Mexico), Carbon Dioxide Process (supercritical CO₂ as a selective solvent, highest flavour retention), Methylene Chloride (chemical solvent decaf, most common commercially), Ethyl Acetate (organic solvent, sometimes marketed as natural), and Sugarcane Decaf (EA from fermented sugarcane, popular in specialty).

Each method affects the final cup differently. CO₂ and Swiss Water are considered the most flavour-preserving; solvent methods are typically cheaper but produce good cup quality in capable hands. For roasters building a decaf offering, the method matters both for cup quality and for the label claims available to them - chemical-free certifications require Swiss Water, Mountain Water, or CO₂ processing.