What Acids and Bases Can I Find in the Kitchen?

Every time you step into your kitchen and cook a meal, you become a chemist for a short time. Although you probably don't think much about it, the ingredients you mix together when you cook or bake are as much about chemical reactions as they are about taste. The acids and bases you use in the kitchen are the reason that a cut of meat gets tender or a cake rises. They can also help you clean up the mess when the cooking is finished.

The pH Scale

When we talk about acids and bases, we're talking about where a substance falls on the pH scale. Ranging from 0 to 14, the pH scale is technically a measure of how many hydrogen atoms are present in a given substance. Substances with a lot of hydrogen have a low pH and are considered to be acidic. Substances with very few hydrogen atoms have a high pH and are basic. Pure water is a neutral 7 on the pH scale and is neither acidic nor basic.

When you take a closer look at the pH scale, it may strike you as odd that battery acid (with a pH of 0) is so close to stomach acid (a pH of 1). This is because a single point on the pH scale represents a 10-fold increase in hydrogen concentration; a two-point difference on the pH scale makes one item 100 times more acidic than another. Thus, lemon juice (pH of 2) is more than 100 times more acidic than black coffee (pH of 5).

Acids in the Kitchen

There are several acids that you may encounter in your kitchen. Vinegar, for instance, has an acidic pH of 2 to 3. Apples have a pH of 4, eggplant has a pH of 5, lemon has a pH of 2, and tomatoes have a pH of 4. When used to cook or marinate meat, acidic foods start to break down the meat and tenderize it. Rubbing a little citric acid in the form of lime or lemon juice can also preserve a food's color and act as a preservative. Sprinkle a little on cut avocados, apples, or pears to keep them from turning brown before you can serve them.

Acids can also help you clean tough stains and spots. Vinegar works well for cleaning glasses that came out of the dishwasher spotty. It also works well on countertops, tile, and most smooth surfaces. A slightly acidic substance, like vinegar or lemon juice, is a good choice for cleaning rust stains, hard water deposits, and tarnish.

Bases in the Kitchen

Chances are you'll find just as many bases in your kitchen as you will acids. Perhaps the most well-known base in the kitchen is baking soda, which has a pH of 8. Most vegetables are also basic and have a pH between 8 and 10. Many fruits are also basic. Grapes, peaches, and bananas are all bases with pH levels of 9, 9, and 8, respectively.

When you cook, basic ingredients feed yeast, cause baked goods to rise, and serve as preservatives in some drinks and salad dressings. Bases also tend to neutralize acids, which is why a mixture of baking soda and water can help treat heartburn. Acids tend to have a bit of a bite when you taste them. If the bite is too strong, a base can often tame it. This is why chefs sometimes add a bit of baking soda to their tomato sauces.

Like acids, bases can help you clean around the house. Bases work well as window cleaners and general surface cleaners. Scouring powders, drain cleaners, and oven cleaners are also very basic and do a good job of breaking down oily dirt. For an extra boost of cleaning power, you can sometimes mix acids and bases. Together, baking soda and vinegar form a fizzy powder that can clean out drains and loosen tough dirt.