The Truth About Cream of Tartar

• Cream of tartar is formed at the bottom of wine barrels. The substance looks chalky and white. It is the acid that makes the wine's grapes tart, also known as potassium hydrogen tartrate. Once the fermented wine is removed from the barrel, the chalky acid is collected, purified and processed into cream of tartar.

Chemical Function

• Cream of tartar works in different ways for different cookie recipes, depending on the other ingredients used. It adds strength to whipped eggs, activates baking soda, stabilizes whipped cream and airy cookie batters such as meringues, and also helps to blend ingredients into a smooth dough with a creamier texture than the batter would achieve without the cream of tartar. The powdery multipurpose ingredient also helps cookies maintain their shapes after they are removed from the oven.

Loss of Cream of Tartar

• Without cream of tartar, expect cookies that flatten right out of the oven into thin, hard, crispy discs. The cookies may have lost their shapes, melting into an indistinguishable blob with the texture of sandpaper. Some cookies may even contain hard chunks of crystallized sugar in them because the cream of tartar was not incorporated into the batter to stop the sugar from binding into crystals. Many a cookie disaster can result from leaving out the required cream of tartar.

Some Easy Fixes

• You usually can tell cream of tartar was left out by looking at that first batch of cookies out of the oven. If you can't find the cream of tartar to fix the problem, consider a few substitutions. Try adding 1/2 teaspoon of lemon juice or 1/2 teaspoon of vinegar for every 1/2 teaspoon of cream of tartar the recipe requires. Both ingredients are acids and perform the same job in the cookie batter as the cream of tartar would. If your cookie dough is too sticky after adding the liquid acid, place the dough into the refrigerator for an hour. The cold dough can be rolled and manipulated as the recipe requires.