What Cream of Tartar Really Is
If you’ve ever baked snickerdoodles or made meringue, you’ve probably encountered cream of tartar in the ingredient list.
It sits in spice racks across America, often in a small container that lasts for years. Most home bakers use it because a recipe calls for it,
not because they understand what it actually is. The name itself offers no clues—there’s no cream involved, and it has nothing to do with tartar sauce.
Cream of tartar is actually a byproduct of winemaking. Its scientific name is potassium bitartrate,
and it forms naturally during the fermentation process when grapes are turned into wine.
As grape juice ferments in barrels, crystals form on the insides of the casks. These crystals are collected, purified,
and ground into the fine white powder sold as cream of tartar
(Healthline).
From Wine Barrels to Baking Powder
The connection between wine and baking might seem strange, but it makes sense when you understand the chemistry.
Cream of tartar is an acid, and in baking, acids are essential for certain chemical reactions.
When combined with baking soda, which is a base, cream of tartar creates carbon dioxide bubbles that help baked goods rise
(Wikipedia).
This combination is actually the basis of baking powder, which is simply cream of tartar and baking soda mixed together with a bit of cornstarch.
For centuries, bakers had to mix their own leavening agents before commercial baking powder became widely available in the late 19th century
(Tartaric.com).
Today, even though baking powder is everywhere, many recipes still call for cream of tartar specifically because of its unique properties beyond just leavening.
Why Recipes Still Call for It
Cream of tartar does more than help things rise. Its most famous use is in stabilizing egg whites.
When you beat egg whites to make meringue or angel food cake, adding a pinch of cream of tartar helps the proteins in the eggs form stronger bonds.
This creates a more stable foam that’s less likely to collapse
(Wikipedia).
It also prevents sugar from crystallizing, which is why it appears in recipes for frostings, candies, and syrups.
When you’re making anything that requires melting sugar, cream of tartar helps keep the mixture smooth instead of grainy
(American International Foods).
In snickerdoodles, cream of tartar serves a different purpose. It gives the cookies their distinctive tangy flavor
and contributes to their characteristic cracked surface. Some bakers describe the taste as slightly sour or tart,
which makes sense given the ingredient’s acidic nature.
The Global Supply Chain
Most cream of tartar comes from wine-producing regions, particularly Italy, France, Spain, and California.
The crystals that form in wine barrels are a natural part of winemaking, so the supply of cream of tartar is directly tied to wine production.
Some winemakers consider it a valuable byproduct, while others see it simply as something to be scraped off and sold
(USDA).
The purification process is relatively simple but important. The raw crystals from wine barrels contain impurities and color from the wine itself.
These crystals are dissolved in hot water, filtered, and then recrystallized to produce the pure white powder that ends up in grocery stores.
The whole process transforms what would otherwise be waste into a useful baking ingredient
(ASBE.org).
Substitutes and Alternatives
If you’re in the middle of baking and realize you’re out of cream of tartar, there are substitutes, though none work exactly the same way.
For stabilizing egg whites, lemon juice or white vinegar can work in a pinch—they’re both acids, after all.
The ratio is typically double the amount of cream of tartar called for in the recipe
(Southern Living).
If a recipe calls for cream of tartar as part of a leavening system with baking soda,
you can usually just substitute baking powder, since it already contains both ingredients.
The general rule is to use three times the amount of baking powder as you would cream of tartar.
For preventing sugar crystallization, corn syrup can sometimes work as a substitute, though it won’t provide the same acidic properties.
And for snickerdoodles, some bakers simply omit the cream of tartar, though the cookies won’t taste quite the same.
Beyond Baking
Cream of tartar has uses outside the kitchen too. It’s an ingredient in some homemade playdough recipes,
where it acts as a preservative and helps create a better texture
(Southern Living).
Some people use it as a cleaning agent, particularly for removing rust stains or cleaning copper cookware.
Mixed with a bit of water to form a paste, it can polish metal surfaces.
It’s also occasionally used in DIY bath bomb recipes, where its acidic properties react with baking soda to create the fizzing effect.
Why the Confusing Name
The “cream” in cream of tartar is misleading—it refers not to dairy cream but to the fact that the crystals form a creamy or crusty layer on wine barrels.
“Tartar” comes from the Latin word tartarum, which was used in medieval times to describe the sediment in wine casks.
So the name essentially means “the crusty stuff from wine barrels,” though that probably wouldn’t sell as well on grocery store shelves.
The confusion over the name has persisted for centuries. Even in old cookbooks, there are references to cooks mixing up cream of tartar with other ingredients
or not understanding its purpose. But despite the confusing name, it has remained a staple in baking for good reason.
A Small Ingredient with Big Impact
Cream of tartar is one of those ingredients that proves chemistry is at the heart of good cooking.
It’s a reminder that many of our everyday foods are the result of careful observation and experimentation over centuries.
The fact that winemakers’ waste product became an essential baking ingredient shows the kind of resourcefulness that has always defined good cooking.
The next time you reach for that small container of white powder to make meringue or snickerdoodles,
you’ll know you’re using crystals that formed on the inside of a wine barrel somewhere.
It’s a connection between two seemingly unrelated processes—winemaking and baking—that has been part of kitchens for hundreds of years.
And now, at least, the mystery of what cream of tartar really is has been solved.
