Extraction temperature
Water temperature at the moment of contact with coffee. Espresso: 92-94°C. Filter: 90-96°C depending on roast (light → higher, dark → lower). Direct impact on aromatic compound solubility.
Background & Context
Extraction temperature is the water temperature at the point of contact with coffee grounds, distinct from the temperature of water entering the kettle or boiler. It is one of the three primary extraction variables (alongside grind size and ratio) and has a significant effect on which compounds are dissolved and at what rate. The SCA brewing standard specifies 90-96°C for filter brewing; espresso standards specify 90-94°C at the group head. Hotter water extracts more compounds faster, raising TDS and EY, but also accelerates the extraction of bitter, astringent compounds (quinic acids, phenols) that degrade cup quality at high temperatures. The current specialty coffee consensus favours brew temperatures of 92-94°C for medium-light roasts and slightly lower (88-91°C) for dark roasts or robusta-heavy blends, where over-extraction of bitter compounds is the primary risk.
Practical Use
Temperature management in home brewing is more complex than it appears. A standard consumer kettle held at boiling (100°C) drops to approximately 93-96°C by the time water reaches the grounds in a pour-over, close to ideal. Variable temperature kettles (Fellow Stagg, Brewista, Bonavita) allow precise targeting. For espresso, machine boiler stability is the key variable: heat exchangers and dual boilers maintain group head temperature more precisely than single boilers, which are subject to thermal cycling. A simple dial-in technique for home baristas: if your espresso tastes under-extracted at correct grind and ratio, try increasing temperature by 1°C; if over-extracted, reduce by 1°C. Each 1°C change has a measurable effect on extraction yield. For Aeropress brewing, which allows the most temperature experimentation of any method, try stepping through 80°C, 85°C, 90°C, and 95°C with identical grind and ratio, the flavour spectrum shift across this range demonstrates temperature's role more vividly than any other technique. Cold brew extraction (0-4°C) compensates for reduced solubility with 12-24 hour contact time, producing a chemically distinct cup with lower acidity and higher sweetness than equivalent hot-extracted coffee.
Related Terms
Related terms: Extraction rate, TDS, Espresso extraction, Over-extraction, Under-extraction.