Appendix A

The Acid Atlas

Acetic is only one sour. Citric, malic, tartaric and lactic each bring a different shape, volatility, and buffer — pick the right one and your dish lands.

What pKa means for cooks

Lower pKa = stronger acid (more H⁺ per gram). Acetic pKa 4.76 is weaker than citric (3.13). That is why 5% vinegar tastes “softer” than 5% lemon juice at the same weight — but acetic acid is volatile, so it hits the nose first.

Volatility matters

Acetic acid evaporates when heated (that sharp pan-deglaze lift). Citric/malic/tartaric stay put — they season through the cook. Use vinegar to finish, citric to build base acidity.

Five acids, compared

Acid	Source	pKa1	Taste / aroma	Buffer feel	Vinegar swap (equiv. to 5% vinegar)
Acetic	Vinegar (fermented ethanol)	4.76	Pungent, nose-first, sharp	Thin, clean	10 mL 5% = 1.0× (reference)
Citric	Lemon/lime, powder	3.13	Bright, fruity, lingering sour	Medium	~3.2 g powder ≈ 10 mL 5% (in 100 mL water)
Malic	Apples, powder	3.40	Green apple, flat, persistent	Medium	~3.5 g ≈ 10 mL 5%
Tartaric	Grapes, wine lees	2.98	Grape, mineral, dry grip	High (wine)	~3.0 g ≈ 10 mL 5%
Lactic	Yogurt, sauerkraut, 88% syrup	3.86	Soft, milky, round — “sour without sharp”	Thick, buffered	~0.6 mL 88% ≈ 10 mL 5%

Equivalents are sensory, not stoichiometric — they assume dilution into ~100 mL liquid. Citric is ~3× stronger by weight, so you need less. Lactic 88% is ~9 M; a few drops go a long way.

When to use which

Goal	Reach for	Why vinegar is not ideal
Finish a pan sauce, gastrique, pickle	Vinegar (sherry, wine, rice)	— this is vinegar’s home: aroma + volatile lift
Brighten a broth/consommé before service	Citric (lemon or powder)	Vinegar would add “pickly” nose; citric stays clean
Green-apple snap in a slaw or caramel	Malic	Acetic too pungent for sweet fruit
Wine-like grip in a red sauce	Tartaric	Vinegar would flatten tannin; tartaric mirrors grape
Round, “fermented” sour — dough, cream, cheese	Lactic	Acetic too thin; lactic’s buffer mimics yogurt
Batch cocktails / milk punch	Citric + malic blend + splash vinegar	See Drinks & The Bar — blend tames acetic nose

Acid chooser — interactive

I am making Target sour

Pick a dish to see the recommendation

Choose above — the Atlas will recommend the acid, the vinegar style if any, and a starting dose per 500 mL liquid.

Starting doses per 500 mL: taste and adjust ±30%. Powders: dissolve in a little water first.

Dosing math — quick reference

5% vinegar → citric: 10 mL 5% acetic ≈ 1.0 g citric (anhydrous) in 100 mL water.
5% vinegar → lactic 88%: 10 mL 5% ≈ 0.6 mL 88% lactic (≈ 0.7 g).
Lemon juice: fresh lemon ~5–6% citric (highly variable), ≈ 8–12 mL juice ≈ 10 mL 5% vinegar in sour power, but without acetic nose.
For preservation (pH ≤ 4.6): only use vinegar- or tested acidified recipes; citric alone at culinary doses may not hold pH without verification. See Preservation calculator.