Wax beans are similar to the common green bean, but are more tender and slightly translucent with yellowish or purplish pods. The best wax beans should be slightly flexible, but not rubbery or soft, with slender pods and bright, clear coloration. Avoid beans that have swollen pods, mature seeds, or pitting and discoloration, as well as any specimens with visible mold or mildew spotting on the pod. Keep your wax beans fresh by storing them in the refrigerator for up to 5 days, and cook them by steaming, stir-frying, or stewing.
These beans are also known as yellow snap beans or string beans, and are sometimes called butter beans, though that name is more commonly used for a kind of large, buttery lima bean. They come in light yellow and purple varieties, though purple wax beans tend to turn green after cooking. You can mix yellow beans with cooked and raw purple beans in salads and other dishes for a striking color contrast.
Choose wax beans that are about 5 inches (13 cm) long and about 3/8 inch (1 cm) thick, with pods that bend slightly but snap under strong pressure. Avoid beans that bend back on themselves easily or have a rubbery texture, as well as any large, stiff beans with swellings along the pod, as these are too old or too mature to cook well. The best beans will have a clear, consistent color throughout the pod, with no signs of insect damage, deformity, or dark spotting from mildew. Moldy beans may have a fluffy white growth near the stem end or along the string, and should not be eaten.
You can keep your wax beans in the best condition by placing them in the crisper drawer of your refrigerator for up to 5 days. If you intend to eat your beans raw or in a salad, store them for a shorter period of time. Beans intended for soups and stews can be used even if they have become slightly soft, though fresher specimens are always better.
Cooking wax beans is much like cooking other string beans, but these more delicate vegetables need a slightly shorter cooking time. Steam or stir-fry wax beans until they are crisp-tender without any crunch, but don't boil them, as this can leave them soggy or mushy. Stew these beans over low heat with tomatoes or other wet, flavorful vegetables so that the beans can absorb the taste of the other food. If using wax beans with foods that need longer cooking, the beans should be added later in the process.
