Citric acid
Also written citric, citric and malic acids
Quick answer
The sharp, clean sourness of citrus and of most dried souring spices — the acid that tastes immediately of sourness and then gets out of the way.
What it does
Citric acid is sour in the most direct sense: a fast, bright, clean sourness that peaks quickly and fades without leaving anything behind. It is the reference point most people carry for what sour means, because it is the dominant acid in lemons and limes. In a spice it reads as lift rather than as body — a squeeze of brightness that does not change the character of the dish it is added to. That is precisely why amchur and dried lime can be used to sour a dish that must not taste of fruit.
How it behaves when cooked
Four properties of the molecule, and what they mean at the stove.
- Volatility
- low
- Fat solubility
- low
- Water solubility
- high
- Heat stability
- high
Highly water-soluble, not volatile and stable to heat, which together mean that a citric souring agent behaves nothing like an aromatic spice. It does not cook off, it does not need blooming in fat, and it disperses instantly into any watery phase — so it can be added at the end and adjusted, which is the opposite of how the aromatics in the same dish must be handled. Two practical consequences follow. Acid added early to a long braise stays at full strength while the liquid reduces around it, so a dish soured at the start is sharper at the end than it was. And because acid slows the softening of pulses and vegetables, a souring spice belongs after the beans are tender rather than before — which is the reason amchur and dried lime are late additions in the traditions that use them.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Malic acid
The other acid in most of these spices, and the difference a cook can taste. Malic is slower, rounder and lingers; citric is sharp and brief. A souring agent where malic dominates reads as fruity, one where citric dominates reads as simply sour.
Tartaric acid
The harsher third acid, prominent in tamarind and in grapes. It is the one that reads as astringent as well as sour, which is why tamarind cannot be replaced by lemon juice without the dish losing a dimension.
Ascorbic acid — vitamin C
Present in citrus alongside citric acid and contributing almost nothing to the taste. The two are routinely conflated, and it is citric acid that makes a lemon sour.
Questions this page answers
- what is citric acid
- what does citric acid do
- which spices contain citric acid