E336 (Potassium tartrates (i) Monopotassium tartrate (cream of tartar) (ii) Dipotassium tartrate)

E336 refers to potassium salts of tartaric acid, mainly potassium tartrate and potassium hydrogen tartrate, known in cooking as cream of tartar. In foods it regulates acidity, gives a dry wine-like sourness and may participate in dough leavening. Unlike many E-numbers, E336 is familiar in home kitchens: cream of tartar is used in baking powders, whipped egg whites, some desserts and powder mixes where a controlled reaction with baking soda or stable acidity is needed.

What cream of tartar is

Cream of tartar is connected with grapes and winemaking. During wine storage, salts of tartaric acid can crystallize. After purification, the acidic potassium tartrate is used as a food ingredient. This does not mean that a product contains alcohol or wine. The name describes the chemical origin and connection with tartaric acid, not an obligatory wine flavor.

Potassium hydrogen tartrate behaves as an acidic component. It is less aromatic than vinegar and does not give the bright citrus profile of citric acid. This makes it useful when clean acidity is needed without extra aroma. In dry mixes it is also valued for predictability: when combined correctly with baking soda, it helps release carbon dioxide.

Role in leavening

Baked goods rise when gas bubbles form inside the dough and the structure holds them. When an acidic component reacts with sodium bicarbonate, carbon dioxide is produced. Cream of tartar can be that acidic component. This is why it appears in baking powders, dry baking mixes and recipes that need mild, controlled leavening.

The speed of the reaction matters. If acid and soda react too early, gas escapes before baking and the product becomes dense. If the reaction is too weak, the structure does not rise well. In industrial mixes, the formula is adjusted for humidity, particle size and temperature. In home cooking, cream of tartar is often useful because it provides an acid part without adding liquid.

Egg whites and desserts

Cream of tartar is often added to whipped egg whites. A slightly acidic environment helps proteins unfold and form a more stable foam. This matters for meringue, souffle, sponge cakes and desserts where volume depends on trapped air bubbles. A small pinch of acid cannot replace proper whipping, clean equipment and gentle folding, but it can reduce the risk of collapse.

In low-carb desserts, this can also be useful. Almond flour, coconut flour, psyllium, erythritol and the absence of gluten all change dough structure, so air and leavening become especially important. E336 does not make a dessert low-carb by itself, but it can help a recipe without sugar and wheat flour become less dense and more stable.

Low-carb relevance

Potassium tartrates are not sugar, starch or syrup. In ordinary amounts they do not add meaningful carbohydrates. For keto and LCHF, the more important issue is the product that contains them. In a baking powder or homemade sugar-free dessert, E336 may be a neutral technical detail. In a sour candy, sweet powder or ordinary baked good, it may appear next to sugar, flour, starch and maltodextrin.

There is also the potassium aspect. Cream of tartar contains potassium, but culinary doses are usually small. A pinch of E336 should not be treated as a full potassium supplement. If electrolytes need correction on a low-carb diet, that belongs to the wider context of diet, symptoms, blood pressure, lab tests and medication, not to the accidental use of cream of tartar in baking.

Tolerance and cautions

In ordinary food amounts, E336 is usually tolerated well. Digestive discomfort is more often related to the surrounding product: sugar alcohols, acidic fizzy drinks, a large amount of baked goods, sweeteners or individual gut sensitivity. In reflux, active gastritis or strong heartburn, acidic components may worsen symptoms, especially when the product is acidic, sweet and carbonated at the same time.

A separate caution concerns potassium. People with chronic kidney disease, a tendency toward high blood potassium or potassium-sparing medicines do not need to panic over traces of E336, but should be more careful with concentrated supplements and large doses of cream of tartar. In such cases, total potassium from foods, salt substitutes, supplements and medications is what matters.

How to read E336 on a label

E336 usually signals an acidity or leavening function. In baking powder, an egg-white dessert or a dry mix, this is a clear technological role. In sweet products it may make flavor brighter and drier, but it does not change the carbohydrate load by itself. The whole ingredient list has to be read, not one E-number alone.

The practical conclusion is balanced. Potassium tartrates do not require automatic avoidance. They are useful in cooking, especially where dry acidity is needed without vinegar smell or lemon aroma. For low-carb eating, flour, sugar, starch and sweeteners decide more. For sensitive digestion, the total acidic load matters. For people with potassium restrictions, the total potassium load matters.