Does Cream of Tartar Go Bad?

I bet you don’t use cream of tartar that often. You probably don’t even remember when you bought the package you’re using right now. And after a few years of storage, you probably wonder: does cream of tartar go bad?

Since cream of tartar (or potassium bitartrate, technically speaking) is in powdered form, you might assume that it basically lasts forever. But since it’s often used in baking as an anti-caking and thickening agent, you probably suspect that it’s somewhat similar to baking soda or baking powder. And that means that it probably loses its potency over time. And as it turns out, you’re quite right.

If you’d like to learn about storage, shelf life, and potency of cream of tartar, this article is for you. Keep reading.

Baking powder
Image used under Creative Commons from Melissa Wiese

How to Store Cream of Tartar

You should store cream of tartar the same way you store its friends, baking soda and baking powder. That means it should sit in a cupboard away from sources of heat and sunlight. While the pantry is the perfect place for it, the kitchen is a slightly more practical choice, especially if you use cream of tartar more often than once a year.

Like other powdered products, cream of tartar has the tendency to draw moisture from the air. Because of that, once you open the container, you need to always keep it tightly sealed. If it comes in paper packaging, it’s probably better to pour the powder into a small jar after opening the package. Paper packaging gives little protection against moisture or any strong odors. Or anything else, for that matter.

How Long Does Cream Of Tartar Last

Like other powdered products, as long as it doesn’t come in contact with water, cream of tartar won’t go bad. That means it basically stays safe to use forever.

However, there’s usually a best-by date on the label. Some producers put it there because of legal requirements, others because people tend to trust food more if it comes with a date. But that date is also quite useful because it gives you an idea for how long you already store the product, and if you need to check its potency before using it. Nevertheless, you can safely assume that the powder should be potent for at least 4 years from its production, and often much longer.

Now let’s talk about checking cream of tartar for potency. If you are unsure if the cream of tartar is still usable, try stirring a half teaspoon of the product into a half cup of warm water. Then, add a pinch of baking soda. If the mixture generates foam, the cream of tartar is still usable for baking, stabilizing egg whites and whipped cream, and so on.

Pantry
Cream of tartar (unopened or opened)Best-by + 6 months

Please note that the period above is only a rough estimate.

Baking: powdered sugar in a sieve
Image used under Creative Commons from Marco Verch

How to Tell If Cream of Tartar Is Bad?

As I mentioned earlier, unless water gets to the container, cream of tartar doesn’t go bad. And even if a small amount of moisture will find its way into the jar, it probably won’t make it grow mold. Instead, it will likely form a few small clumps, that you can get rid of by running it through a spice grinder, a sieve, or by using mortar and pestle.

But if more moisture gets into the jar, the powder will go bad. If it has turned into a solid lump, or there is any mold or any other organic growth on the surface, it’s time for it to go. Same thing if has changed color or there are some dark specks here and there. And as usual, an off odor is a sure sign you should discard the powder.

If everything about the product seems to be okay, but you store it for a very long time, test its potency before using. This way you can make sure it won’t ruin the dish you’re making, and you won’t have to start from scratch.