Читать книгу Canning & Preserving For Dummies - Amelia Jeanroy - Страница 65

You can safely water-bath can only high-acid foods — those with a pH factor (the measure of acidity) of 4.6 or lower. So just what is a high-acid food? Either of the following.

 Foods that are naturally high in acid: These foods include most fruits.

 Low-acid foods that you add acid to, thus converting them into a high-acid food. Pickled vegetables fall into this category, making them safe for water-bath canning.You may change the acid level in low-acid foods by adding an acid, such as vinegar, lemon juice, or citric acid, a white powder extracted from the juice of acidic fruits such as lemons, limes, or pineapples. Some examples of altered low-acid foods are pickles made from cucumbers, relish made from zucchini or summer squash, and green beans flavored with dill. Today, tomatoes tend to fall into this category. They can be water-bath canned, but for safety’s sake, you add a form of acid to them.

If your recipe doesn’t tell you which processing method (water-bath canning or pressure canning) is appropriate for your food, don’t guess. Instead, use litmus paper to test the pH level of your food (see Chapter 3). If your food has a pH of 4.6 or lower, use the water-bath canning method; if it has a pH of 4.7 or higher, use the pressure-canning method.