Too Much Cream of Tartar? How to Fix It, and When It’s a Safety Issue

Cream of tartar is used in small amounts, so too much is usually a measuring slip: a tablespoon instead of a teaspoon, or a teaspoon where a pinch was meant. In baking, the problem is flavor. As something swallowed by the spoonful, it is a real safety issue, covered below.

Quick answer

What cream of tartar is and what it does

Cream of tartar is potassium bitartrate, a byproduct of winemaking.² Bakers use it as a weak acid. It stabilizes whipped egg whites by lowering their pH,² and America’s Test Kitchen found that a meringue made without it wept beads of moisture while one made with it stayed dry and smooth.³ It also helps prevent sugar crystallizing in syrups and candy, and it can be combined with baking soda as a stand-in for baking powder.²

Recipes use very little. King Arthur notes that recipes often call for a pinch to 1/8 teaspoon per egg white,² and ATK’s test meringue used 1/2 teaspoon for four whites.³

What too much does to food

The clearest sourced effect is taste. King Arthur says too much cream of tartar gives a metallic, tin-like taste, and the post includes a recipe developer’s account of a batch of soufflé pancakes made with too much.²

It’s sometimes said that too much makes cakes fall or frosting set rock hard. We found no source that tested this, so we can’t say whether, or at what amount, it happens.

Fixes

Remove it before it’s mixed in. If you’ve just dumped extra cream of tartar onto flour and sugar, spoon out the mound and a little of what’s under it. Once stirred into other white powders, it can’t be picked out; in our judgment, discarding a bowl of dry ingredients costs less than a failed cake.

Scale up everything else. If you know how much you added, increase every other ingredient by the same factor. Twice the cream of tartar calls for twice everything else. To avoid a double batch, split the mix in half and bring one half back up to a full recipe with fresh ingredients (no added cream of tartar), then save or discard the other half.

Mask it after baking. On a cake or cookies that are already baked, a well-flavored frosting, a chocolate ganache or a tart fruit topping gives each bite something else to taste. We found no source testing whether sugar suppresses a metallic taste specifically, so think of this as covering it, not correcting it.

Start over. For meringues, where the amount is a small fraction of a teaspoon per egg white,² a fresh batch is usually the quickest and cheapest route.

Safety: large amounts can be dangerous

Because it’s potassium bitartrate, cream of tartar is a concentrated source of potassium: 100 grams contains 16.5 grams of potassium, according to a 2025 case report in the Medical Journal of Australia.⁴ That works out to about 165 milligrams of potassium per gram of cream of tartar.

The case report describes a woman who swallowed 166 grams of cream of tartar as a home remedy for constipation; her history mentioned an online video. She developed severe hyperkalemia (dangerously high blood potassium), had two cardiac arrests, needed dialysis, and recovered.⁴ The authors call it the third reported case in 11 years and cite two earlier cases, reported in 2013 by Rusyniak and colleagues, in healthy young men who took it to “clean themselves out.”⁴ They call for warning labels on packaging.⁴

Keep that in proportion. The amounts used in baking are a pinch to a fraction of a teaspoon spread across a whole recipe,² nowhere near the doses in these cases. A cake with a measuring mistake is a flavor problem. Swallowing cream of tartar by the spoonful as a cleanse, laxative or home remedy is not safe; if someone has, call Poison Control at 1-800-222-1222 in the U.S.¹

Preventing it next time

Read “tsp” and “tbsp” twice. A tablespoon is three times a teaspoon, and cream of tartar recipes often use fractions of a teaspoon.

Measure over a separate bowl, not over the batter, so a spill doesn’t end up in the mix. This is common kitchen practice.

Use the recipe’s amount for egg whites. A pinch to 1/8 teaspoon per egg white is the range King Arthur reports recipes using.²

Related

• Too much sugar
• Too much salt
• Too much vanilla