Cream of Tartar

Food · Pantry & Condiment · Food, Typed Supps

An acid powder for baking — the huge potassium number on the table is per 100g, and a recipe uses about a gram.

Stage by stage

In the bowl (Acts before eating): Lowers pH in egg whites and reacts with bicarbonate to leaven — most of its purpose is served before it is eaten.
Digestion (Salt dissociates): What is eaten dissolves; the potassium separates from the poorly absorbed tartrate.
Absorption (Potassium taken up): Potassium is absorbed in the small intestine, roughly 165mg from a typical quarter-teaspoon.
Whole diet (Contribution is minor): At culinary doses the contribution to daily potassium is small; larger doses are limited by a laxative effect.

Time to effect

Not applicable: Its effects are on the food rather than on the body; there is no meaningful nutritional timeline at culinary doses.

Allergens

None of the fourteen major allergens. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegetarian, Pescatarian, Halal, Kosher, Keto, Gluten-free. Depends on the product: Low-FODMAP.

Satiety

Not scored: the satiety index is measured on 240 kcal servings, and nobody eats a 240 kcal serving of this. The question does not apply rather than the answer being unknown.

Cost band

Mid — roughly £8 per kg, as a band midpoint rather than a price.

Key nutrients

Potassium (per 100g, not per serve)
Tartaric acid

Nutrition per 100g

Calories: 0
Protein: 0g
Carbohydrate: 0g
of which sugars: 0g
Fat: 0g
of which saturated: 0g
Fibre: 0.2g
Sodium: 52mg

Food vs. supplement

Not a sensible supplement. Potassium from vegetables, legumes and fruit arrives with the rest of the diet and without the acid load and laxative effect that cap the dose here.

Kitchen tip

An eighth of a teaspoon per egg white makes a meringue that holds. Two parts cream of tartar to one part bicarbonate of soda is homemade baking powder.

Common myth

“It is a cheap way to top up your potassium.” In reality: At culinary doses it supplies about as much potassium as a few mouthfuls of banana. At the doses that would supply more, it acts as a laxative and has caused dangerous hyperkalaemia in people with impaired kidney function.