A speciality coffee flavour note across London.
Purple acidity refers to a specific quality of tartness in the cup that is deep, almost juicy, and reminiscent of dark berries such as blackcurrant, blackberry, or damson plum. It sits differently from the brighter, sharper citric acidity found in lighter coffees, feeling rounder and more lingering on the palate. This character is typically associated with higher concentrations of malic and citric acids alongside fruit-forward fermentation compounds, and is most pronounced in lightly roasted beans where these volatile notes are preserved.
Coffees from Ethiopia, particularly those from the Yirgacheffe and Sidama regions, often express this quality, especially when processed using natural or anaerobic fermentation methods that allow the fruit to impart deeper, darker berry characteristics to the bean. Burundian and Rwandan lots with longer fermentation periods can also tend towards this profile, as can some Kenyan washed coffees where phosphoric acid contributes a distinctly deep, grape-like quality. Processing method plays a considerable role, and naturally processed coffees are typically more likely to carry this note than cleanly washed equivalents from the same origin.
On a bag or cafe menu, look for tasting notes such as blackcurrant, blackberry, dark cherry, damson, or grape, which suggest a coffee is likely to carry this quality of acidity. Words like "natural process", "anaerobic", or "extended fermentation" in the processing description are useful indicators. Pour-over and filter methods such as V60 or Chemex tend to highlight this note clearly, as they preserve brightness and separation of flavour in ways that espresso or immersion brewing may soften or obscure.
Take our 60-second flavour quiz and discover roasts across London that are aligned with your palate — including ones carrying purple acidity notes.