Sour
Acidity past the point of brightness. Usually acetic acid trapped in the bean by drying that went too fast.
Sourness is what acidity becomes when there is too much of it, and in chocolate it is overwhelmingly a drying problem rather than a fermentation one. Fermentation produces acetic acid by design; slow drying lets it evaporate out. Fast artificial drying case-hardens the bean's exterior and seals the acid inside, where it stays through roasting, conching and into the finished bar.
That is why the same well-fermented beans can produce a bright bar or a vinegary one depending on a step that happens after the fermentation is over.
- Descriptors used
- vinegar, sharp, sour, acetic, harsh
- Desirable?
- A fault at high levels. The boundary with desirable brightness is genuinely a matter of preference.
Where it comes from
The route by which this note arrives in the chocolate.
Shaped by conching
InferredConching drives off volatile acids, so a very short conche leaves more acidity in the finished chocolate.
How to tell: Sourness in an otherwise well-made craft bar is often a deliberately short conche rather than a drying fault.
Source: Royal Society of Chemistry
When it is a fault
Case hardening during fast drying traps acetic acid inside the bean, where nothing downstream removes it.
How to tell: Trapped acid is one-dimensional and sits on top of the chocolate with no aromatic component. Genuine citrus brightness has peel and zest character alongside it.
Related
Covered in
- Chocolate tasting vocabularyHalf of the second most commonly confused pair.
Compared in
- Acidity vs sournessSet against Acidity, which readers frequently believe is the same thing.
Developed during
- Artificial dryingThis stage is where the note is created, amplified or destroyed. Acidity past the point of brightness. Usually acetic acid trapped in the bean by drying that went too fast.
- ConchingThis stage is where the note is created, amplified or destroyed. Acidity past the point of brightness. Usually acetic acid trapped in the bean by drying that went too fast.
Sources
- ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)
- Chocolate Science and Technology — Wiley-Blackwell(citation identity confirmed; passage not re-read)