What actually is cream of tartar? - Ingredient Guide

by India Tarasin

Jun 05, 2026

So many of our favourite baking recipes call for this mysterious ingredient, but what is it?

You’d be forgiven if your mind immediately went to the dairy aisle when you heard the words ‘cream of tartar’. Is it a form of sour cream? Or something to do with tartar sauce? Am I too far gone in life to be questioning the ins and outs of this so-called household staple?

But fear not. Despite what its name might suggest, this common baking ingredient is actually far less confusing than you might think.

With origins dating back thousands of years, cream of tartar has an unusual backstory that’s linked, somewhat unexpectedly, to wine.

Yes, really. It turns out that cream of tartar may have more in common with your favourite bottle of pinot than you ever thought.

What is cream of tartar?

Cream of tartar is a common baking ingredient, found in the baking aisle of any supermarket. It looks like an odourless white powder, and has various functions in baking (read on for these).

Where does cream of tartar come from?

Despite its misleading name, cream of tartar doesn’t actually contain any cream, tartar sauce or dairy. In fact, the baking ingredient is made from tartaric acid, a natural byproduct of the winemaking process.

During the fermentation and ageing processes of winemaking, the tartaric acid found naturally in grapes crystallises and collects on the inside of wine barrels and storage tanks. These crystals, known as potassium bitartrate, form a hard sediment that winemakers have had to deal with for centuries. Once collected, the crystals are purified and ground into the powder that eventually ends up in the small jars lining supermarket baking aisles.

So why the confusing name?

Historically, the deposit left behind in wine barrels was known as ‘tartar’. The ‘cream’ part is thought to come from the purification process. When the tartar is dissolved in hot water, the purest and whitest crystals separate out, much like cream rising to the top of milk. The result is ‘cream of tartar’ – a name rooted in centuries-old winemaking traditions rather than anything you’d find next to the cream in the supermarket.

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What does cream of tartar do in baking?

Cream of tartar may seem like one of those mysterious baking ingredients that is forever just sitting in the pantry, but it actually does a lot of important work.

Basically, it’s used to stabilise whipped egg whites, helping them hold their shape and create the light, airy texture needed for recipes like meringues, souffles and super-soft sponge cakes. It can also help prevent sugar from crystallising, which is why it’s often added to icings and syrups.

Cream of tartar can also work as a leavening agent. When it’s combined with baking soda, the two react to produce carbon dioxide bubbles that help baked goods rise. This reaction creates a lighter texture in cakes, cookies and quick breads. In fact, this nifty item is one of the main ingredients in baking powder, which is why it shows up in so many recipes.

What can you substitute for cream of tartar?

If you don’t have cream of tartar at home, don’t worry! In many cases, you can swap it for something you already have. A little lemon juice or white vinegar can provide the same acidity when you’re whipping egg whites, while baking powder can often stand in for recipes that use cream of tartar alongside baking soda. While the results may vary slightly, these easy substitutes can save a trip to the shops and keep your baking plans on track.

So there you have it. Mystery unlocked! The next time a recipe calls for cream of tartar, you’ll know exactly why it’s there – and what to do if it isn’t.