Cream of tartar is an acidic, powdery byproduct of winemaking that bakers use to stabilize mixtures, control texture, and sometimes help things rise.

What cream of tartar actually is

  • It’s potassium bitartrate, a white, acidic salt that crystallizes inside wine barrels and is then purified and ground into a fine powder.
  • It’s considered safe in small culinary amounts and is sold in the spice/baking aisle in tiny jars because a little goes a long way.

What does cream of tartar do in baking?

  • Stabilizes egg whites: It makes whipped egg whites (for meringues, macarons, soufflĂ©s, angel food cake) more stable, glossier, and less likely to deflate, by lowering pH and slowing the proteins from clumping together.
  • Controls sugar crystallization: It helps prevent sugar from crystallizing into gritty chunks in candies, caramel, syrups, and frostings, leading to smoother textures.
  • Adds chewiness to cookies: In cookies like snickerdoodles, it keeps sugar from crystallizing fully, which makes the cookie more chewy than crisp.
  • Adds a gentle tang: Its mild acidity gives snickerdoodles and some old‑fashioned cookies their characteristic tangy flavor.
  • Helps with leavening: When combined with baking soda, it forms the acidic half of homemade baking powder, producing carbon dioxide bubbles that help doughs and batters rise.

Quick example

  • Snickerdoodles: cream of tartar + baking soda = rise, chewiness, and that signature tangy flavor, plus less browning so the cookie stays pale and soft.

Other kitchen uses

  • Stabilizes whipped cream: A pinch can help whipped cream hold its shape a bit longer without becoming grainy or weeping as fast.
  • Helps jams and syrups: By interfering with sugar crystallization, it keeps jams, jellies, and syrups smoother and less likely to turn sandy.
  • DIY baking powder: You can mix baking soda and cream of tartar to imitate baking powder in a pinch (common ratio is about 2 parts cream of tartar to 1 part baking soda, used right away).

Non‑food uses

  • Gentle cleaner: Mixed with vinegar or water, it can polish metals like stainless steel and aluminum or help lift some stains, thanks to its mild acidity.
  • Rust and stain treatment: Paste mixtures with cream of tartar sometimes help loosen rust or tough fabric stains before washing.

Health notes (brief)

  • It’s about 20% potassium by weight, so large medicinal “hack” doses (for example, for migraines, blood pressure, or “detox”) are not recommended and can raise potassium to dangerous levels.
  • The only health effect with real scientific support is that fairly high, controlled doses can act as a laxative, but this is not a routine home remedy and should not be done without medical guidance.

TL;DR: In everyday cooking, cream of tartar’s main jobs are: stabilize egg whites and whipped cream, keep sugar smooth (not gritty), add chew and tang to cookies, and partner with baking soda to help baked goods rise.

Information gathered from public forums or data available on the internet and portrayed here.