The real answer is that cream of tartar does not expire in the traditional sense. It won’t make you sick if you use an old jar. But it does lose its chemical potency over time.
That means your meringues won’t get as stiff, and your cookies might spread into sad little puddles. That is the bad kind of bad.
Think of it like last year’s sunscreen: it still smells nice, but it’s not doing the job you need it to do.
How to Know if Yours Is Still Good
First, check the texture. If it’s clumpy or has absorbed moisture, it’s probably past its prime. Fresh cream of tartar is a fine, free-flowing powder.
Second, do the sniff test – seriously. It should have a clean, almost neutral scent. If it smells funky or musty, toss it. That’s a sign of pantry ghosts.
Finally, the best test: mix a tiny pinch with warm water and a drop of baking soda. Fresh cream of tartar will fizz like a science fair volcano. No fizz? It’s flat.
Does Cream Of Tartar Go Bad | PokPokSom
