Chocolate, Coffee & Drinks
Roasting changes coffee acidity and bitterness, but the supplied studies do not support a simple rule that every darker roast is always less acidic and more bitter. Acidity can rise during roasting and then fall later—titratable acidity peaked around first crack and returned to its starting value by second crack in one study—while roast level also affected measured sensory acidity and bitterness. The direction and size of the change depend on the roast profile, coffee, and brewing method.
For acidity, roast progression appears to alter the acids and their extraction. One study found that titratable acidity, which is correlated with perceived sourness, peaked during first crack and then declined by second crack; another reported that roast time and roast degree had linear effects on acidity, without giving a universal direction in the abstract. For bitterness, the direct evidence here is more limited: an electronic-tongue study found that roast level significantly affected acidity and bitterness, but its abstract does not state whether bitterness consistently increased with darker roasting. Brewing conditions also matter: cold brewing produced lower acidity and fewer dissolved solids than hot brewing, and darker roasts had lower concentrations of some measured compounds in both methods.
Answer last checked 2026-08-18T13:33:26.711Z. Answerlog reads titles and abstracts, not full papers, and does not assess study quality or claim consensus.