Understanding the Science of Cream of Tartar
Cream of tartar, or potassium bitartrate, is an acidic salt derived from the sediment left behind during wine fermentation. In the kitchen, its primary purpose isn't to add flavor, but to act as a stabilizing agent and an interfering agent. Its acidic nature is key to its functionality, influencing the chemical reactions of other ingredients in baking and cooking. A simple pinch of this white powder can have a significant impact on the texture, structure, and color of your food.
Prevents the Collapse of Whipped Egg Whites
One of cream of tartar's most famous uses is its ability to stabilize whipped egg whites, which is crucial for creating airy meringues, light angel food cakes, and lofty soufflés. When egg whites are whipped, the proteins stretch and trap air bubbles, forming a foam. The addition of cream of tartar, an acid, works to denature (uncurl) the egg white proteins and prevent them from bonding too tightly. This results in a stronger, more elastic foam that is less likely to collapse or 'weep' (seep liquid).
How it stabilizes egg whites:
- It lowers the pH of the egg whites, which changes the electrical charge of the protein molecules.
- This discourages the proteins from bonding too tightly, which would squeeze out water and cause the foam to collapse.
- The result is a more resilient foam that can be beaten to stiff peaks and hold its structure better during baking.
Stops Sugar Crystallization
When making syrups, icings, or candy, the goal is often a smooth, non-gritty texture. This can be challenging, as sugar molecules (sucrose) have a tendency to bond together and form large, crunchy crystals. Cream of tartar, when added to a boiling sugar solution, prevents this crystallization from occurring. The acid in cream of tartar inverts sucrose, breaking it down into smaller, simpler molecules of glucose and fructose. The presence of these different-sized molecules interferes with the sugar's ability to lock into a crystalline structure, resulting in a smooth finish. This is why cream of tartar is a key ingredient in recipes for things like divinity and homemade marshmallows.
Inhibits Discoloration in Fruits and Vegetables
Beyond baking, cream of tartar is an excellent preventative measure against unwanted discoloration in produce. This is due to its acidic properties, which can help preserve color and brightness. For example, adding a small amount to the water when boiling vegetables like green beans, asparagus, or cauliflower helps them retain their vibrant color. It also works to prevent enzymatic browning in cut fruits, similar to lemon juice, making it useful for fruit salads or when preparing produce in advance.
Creates a Chewier Texture in Cookies
Snickerdoodles are a prime example of cream of tartar's role in affecting texture. The chewiness that defines a perfect snickerdoodle comes from the cream of tartar preventing the sugar in the dough from crystallizing during baking. Without it, the cookies would be much crispier, more like a traditional sugar cookie.
Activates Leavening with Baking Soda
While not preventing something from forming on its own, cream of tartar is often used in combination with baking soda to create a leavening agent. This homemade version of baking powder creates carbon dioxide gas, which causes baked goods to rise and become light and airy. The benefit of this approach is that cream of tartar has an indefinite shelf life when stored properly, while pre-mixed baking powder can lose its potency over time.
Comparison: Cream of Tartar vs. Common Substitutes
| Feature | Cream of Tartar | Lemon Juice | White Vinegar |
|---|---|---|---|
| Function | Stabilizes egg whites, prevents sugar crystallization, acts as leavening acid | Stabilizes egg whites, prevents browning | Stabilizes egg whites, acts as leavening acid |
| Usage Ratio (Approximate) | 1/8 tsp per egg white, or as recipe dictates | 1/4 tsp per egg white | 1/4 tsp per egg white |
| Flavor Impact | Mildly tangy, can add flavor to cookies like snickerdoodles | Potentially strong lemony flavor, can affect final taste | Pungent, more likely to affect final taste if used in large quantity |
| Effectiveness | Highly effective stabilizer for egg whites and sugar | Effective, but can add unwanted flavor | Effective, but can add unwanted flavor |
| Texture | Promotes a fine crumb and chewy texture | Can sometimes add excess liquid to recipes | Can sometimes add excess liquid to recipes |
Conclusion: The Versatile Kitchen Aid
In conclusion, cream of tartar is far more than a simple pantry ingredient; it is a powerful agent for preventing numerous baking and cooking pitfalls. From ensuring your meringue stays fluffy and your candy remains smooth, to keeping your vegetables bright and your cookies delightfully chewy, its acidic properties are invaluable. Understanding what cream of tartar prevents from forming gives you a deeper control over your culinary creations and the confidence to master new recipes. The next time a recipe calls for this humble powder, you'll know precisely the magic it's performing behind the scenes. For more baking tips and recipes, explore resources like King Arthur Baking.
Substitutes for Cream of Tartar
If you find yourself in a pinch without cream of tartar, there are several viable substitutions, depending on the recipe's purpose. For stabilizing egg whites, you can use a small amount of lemon juice or white vinegar, typically using twice the amount of the liquid as you would the powder. For leavening, you can substitute baking powder, which already contains a mix of acid and baking soda. However, for specific recipes like snickerdoodles where the tangy flavor is crucial, a perfect substitute is harder to find.
Other Interesting Uses
Beyond its starring roles in baking, cream of tartar has a few other notable uses:
- Stabilizing Whipped Cream: Adding a pinch of cream of tartar can help whipped cream hold its shape longer and prevent it from deflating.
- Household Cleaner: It can be combined with other household products to create a non-toxic paste for polishing metals, including stainless steel and copper.
- Play Dough: It is a key ingredient in many recipes for homemade play dough, providing a pliable texture.
