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E336AcidulantLow concern
Potassium Tartrate
In plain words
The short version
Cream of tartar — the slow acid in classic baking powders.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
EFSA (2020) set a group ADI of 240 mg/kg body weight per day for L(+)-tartaric acid and its salts (E 334–337, E 354), expressed as tartaric acid. JECFA's ADI is 0–30 mg/kg body weight. Negligible toxicity; very high doses are laxative. Long history of safe use in home and commercial baking.
The detail
Crystallizes out of wine during fermentation as a natural by-product (the deposit on the inside of barrels and stoppers). Purified by recrystallization. Cream of tartar is the monopotassium form (KHC4H4O6).
The acid component of classic baking powders, where it reacts with bicarbonate (E500) on hydration to release CO2 — a slow, dough-cool leavening. Also stabilizes whipped egg whites and meringues (acidifies and chelates trace metals), prevents sugar-syrup crystallization, and gives angel-food cakes their characteristic texture.
White crystalline powder, sparingly soluble in cold water, more soluble in hot. Mildly acidic. Stable in dry storage.
Permitted globally without restrictive limits.
Sources
- EFSA — Re-evaluation of L(+)-tartaric acid (E 334), sodium tartrates (E 335), potassium tartrates (E 336), potassium sodium tartrate (E 337) and calcium tartrate (E 354) as food additives (EFSA Journal 2020;18(3):6030) — European Food Safety Authority (EFSA), FAF Panel, 2020. Safety: group ADI covering potassium tartrates (E 336)
- 21 CFR 184.1077 — Potassium acid tartrate (cream of tartar, GRAS), eCFR — U.S. FDA / eCFR (Office of the Federal Register), 1983. Identity as cream of tartar and US GRAS status (leavening agent, baked goods, candies)
- WHO JECFA database — Potassium L(+)-tartrate (INS 336(ii)) — Joint FAO/WHO Expert Committee on Food Additives (JECFA), 1973. Safety: JECFA ADI 0–30 mg/kg bw expressed as L(+)-tartaric acid
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.