Beans cook by absorbing water in the presence of heat. Their ability to absorb water means they double or triple in volume when you soak them, and increase in volume slightly when you cook them. The first key to cooking beans is to use enough water. Make sure the level of the cooking liquid is 1 1/2 to 2 inches above the beans.

More than the variety of bean or whether the pot is covered, age and degree of dryness determine how quickly any given batch of beans will cook. This is why many recipes give an estimated time, usually with a range between 60 and 90 minutes. Unless the beans look dusty or have a musty smell, you cannot determine exactly how dry they are, and dusty, musty odors suggest the beans are too old and you need to throw them out. Some bean varieties take longer to cook than others, so check the package instructions. The hardness of your water can also make a difference in how long beans have to cook to become tender. According to the United States Dry Bean Council, adding 1/4 teaspoon of baking soda per 1 pound of beans to hard water can help make sure the beans become tender, although it causes damage to part of the thiamine beans contain.

Proponents of cooking beans uncovered suggest the steam removes some of the indigestible sugars that make beans gassy for some people. Uncovered beans become tender without getting mushy. The secret to uncovered bean cooking is frequent monitoring of the liquid level and adding water when needed. Occasional stirring helps the beans cook evenly. Use the open-pot method when the beans need to be tender but intact, such as for a casserole or a salad.

Covering the pot traps and recirculates much of the moisture that would evaporate as steam. Setting the lid ajar lets just enough steam escape to keep the pot from boiling over. You will still need to check the liquid level and stir the beans occasionally. Critics of this method suggest that beans are more likely to get mushy and burst through their skins than with the open-pot method. Cook beans covered if they don't need to be firm and well shaped, such as for a soup or puree.

The only way to significantly reduce how long it takes to cook beans is with a pressure-cooker. Depending on the variety of bean, the brand of cooker and the pressure level, cooking time, including cool-down, can be reduced to less than an hour. Follow the directions for your particular pressure cooker. According to the United States Dry Bean Council, microwaving will not produce similar results. Microwaving beans can take as long as conventional cooking. Use your pressure cooker when time matters.