Become a fan of h2g2
Beans have been a part of our diet since man began to cultivate plants. They are high in protein1 and are less costly to produce than high protein animal products. Many different varieties are grown all over the world, in gardens and commercially for food; both for human consumption and for livestock.
This entry looks at the many varieties of beans worldwide, why they are so good for us, how to grow them and how to cook them. There are some golden rules, some rules of thumb and one warning.
What is a Bean?
All beans are members of the Leguminosae family of plants, commonly known as legumes, which includes both beans and peas. It is the third largest family of flowering plants after orchids and daisies. They are natives of four continents: Europe, Africa, Asia and South America.
A bean is composed of a seed coat containing an embryonic plant and a pair of cotyledons2. The bean that we eat may not simply be a seed. Some of the vegetables that we call beans include the seed pod, as well as the seed itself. Runner beans are one example.
From Europe and Southwest Asia
- Fava, or broad bean
- Chickpea, or garbanzo bean
From India and East Asia
- Azuki bean
- Rice bean
- Winged bean
- Black eyed pea
From South America
- Haricot bean
- Butter bean
- Runner bean
As well as being useful crops, beans come in a variety of colours; pods and seeds can be yellow, green, red, white, blue or a mixture of colours.
Wouldn't eat beans
The ancient brotherhood of Pythagoras, who flourished in the Ancient Greek city of Alexandria, believed in reincarnation. They wouldn't eat meat because it might contain the soul of a person. But they also believed that dead spirits might return to this world as beans, so beans were also proscribed from their diet. A pity, because in the absence of meat, they were missing out on a valuable source of protein.
It is interesting to note that each of the four major legumes known to the Romans lent their name to a prominent family: Fabius from the fava (or broad) bean; Lentulus from the lentil; Piso from the pea; and Cicero from the chickpea.
The Nutritional Value of Beans
Beans are a good source of several nutrients, including iron, protein, B vitamins, folic acid and oil or starch. Beans with coloured shells contain antioxidants. They are a rich source of fibre, which helps to reduce levels of LDL cholesterol in blood. Fibre is also known as 'roughage' and is important because it absorbs water, adds bulk and ensures that wastes pass out of the body efficiently. If this does not happen several problems can occur including constipation and diverticular disease.
Soya beans are the stars of the bean world. They are the only beans to contain all eight amino acids necessary to make a 'complete' protein. They also contain photoestrogens, which are thought to slow bone loss, reduce the chances of prostate cancer and heart disease.
Growing Beans at Home
It is simple and satisfying to grow your own beans. They are warm climate crops, which will nonetheless grow in a temperate climate summer. They can be grown as pod or snap beans, where one eats seed and pod alike, shell beans, where the immature bean is eaten, and as dry beans, where the mature seed is consumed.
In the Garden
The four key requirements to grow any bean crop are sunshine, warmth, water and soil packed with compost or manure. The sunnier the summer, the bigger your bean crop. The warmer the summer,3 the bigger your bean crop. The more compost that you put into, or on top of, your soil the bigger your bean crop. The high compost content of the soil results in good water retention and the soil needs to be moist at all times.
Bean seeds can be bought from seed suppliers, bought from the shops and sown, or easily collected from your previous season's crop. In areas where frosts last into the late spring, beans should be sown indoors in small pots or trays in a warm atmosphere. The seedlings can be planted out once the frosts are over and when the soil has begun to warm up. In areas without spring frosts, seeds can be planted directly into the ground where you want them to grow. The soil should be above 50°F (10°C) as a rule of thumb to avoid rot or poor germination. The plants should be about six inches apart, but check the instructions on the seed packet for specifics. Keep the bean patch weeded throughout the growing season, or keep it well-mulched with something like grass cuttings. Supports for climbing beans should be put into the ground before the seeds are sown, or seedlings planted out. Beans do not like to have their roots disturbed.
Many warm or hot climate varieties of bean can be grown successfully in temperate climates if you use a greenhouse, sunroom or polytunnel. Plant them into large, deep and well-composted tubs in the full sun. The tubs will need to be well-drained and placed onto a tray, so that you can monitor water uptake. There should always be standing water in the tray. Indoor beans may well require ventilation on very hot or sunny days, to prevent leaf-scorch.
Another method of growing beans indoors is to sprout beans. Just about all bean varieties can be sprouted. For one volume of beans, add four volumes of warm water to soak overnight. Drain the beans and place them in a large jar, covered with a piece of muslin or cheesecloth and secured with a rubber band. They should be kept in a warm place and rinsed thoroughly with water once or twice a day. Beans are ready to eat once the sprouts are an inch long.
Types of Bean
Different types of bean are harvested at different stages of their growth. Shell beans are picked once the pods are firm and crisp, showing the shape of the bean inside. Pod beans are picked when the seeds in the pod appear plump and firm. Dry beans are picked once the pod is dried and looks dead.
Pod or Snap Beans
These include runner beans, French beans and winged beans; all of which are sometimes referred to as string beans because of the stringy fibre that develops along the seam of the pod if they are overripe. They are also called pole beans in some countries, due to their climbing nature. Pick pod beans and eat or preserve immediately. The flesh of the pod deteriorates quickly once they are harvested and will go limp even in the fridge.
Broad and butter beans are harvested when the seeds are fully formed but still immature inside the pod. They should be eaten or preserved immediately after picking.
These include kidney beans, pinto beans, borlotti beans and many others. They need a longer growing season than either pod or shell beans to provide time for the beans to reach full maturity. Once harvested they can be used in the kitchen straight away, or dried in a warm dry place for storage.
Many bean varieties can be grown as pod or dry beans. For example, soya beans can be harvested when the pods are just two inches long and eaten whole4, or left to mature and dried. Borlotti beans, winged beans, runner beans and French beans are also similarly versatile.
Pod and shell beans should be preserved as soon as possible after they are picked. Freezing is the most successful method of storage. Blanch the beans in boiling unsalted water for 30 seconds, plunge them into cold water, drain and pack into plastic bags and put into the fast freeze compartment of the freezer. Pod and shell beans can also be salted, pickled, used in chutneys and relishes, or cooked in soups and casseroles which can then be frozen.
Dry beans should be removed from their pods and placed in a warm, dry place until they are completely dry. Put them into an airtight container and they will keep for months until they are required in the kitchen. Be warned that the longer you keep dry beans, the longer they take to rehydrate later on.
Fresh pod and shell beans are delicious cooked simply, so that their sweetness can be tasted unadulterated. Steaming preserves more of the taste and texture. They can be eaten hot, with butter and seasoning, or in a salad. The first dish of the summer of steamed Broad beans served with a knob of butter, salt and pepper, is arguably one of the highlights of the kitchen gardener's year, not least because broad beans are the first variety to reach maturity.
Beans that are past their best and are a little tough or starchy can be used in soups, casseroles and savoury bakes, where they can be cooked longer to soften them up. Broad beans that are not quite as fresh and sweet as that first dish can make a wonderful vegetable dish when steamed and served with a parsley sauce.
Cooking pod and shell beans that have been frozen is easy. Simply defrost them at room temperature and put them into a pan with a knob of butter, salt and pepper. Cover the pan and put over a medium heat for five to ten minutes until the beans are tender. Eat immediately. They do not taste quite as good as fresh picks, but they will be a lot better than beans that are sold in the vegetable sections in the supermarket.
Dry beans should be cooked quite differently, even if they have just been harvested. Fresh dry beans will require at least 30 minutes simmering in unsalted water or stock before they are edible. Dried dry beans should be soaked overnight in water to help to rehydrate and soften them. Most will triple in size, so make sure there is plenty of room in your bowl.
Cook them in a large pan using three times as much water as beans. Boil them hard for 15 minutes initially, and then simmer gently until they are soft. This can be between one and two hours, depending upon the variety. Keep the beans covered with water throughout cooking. Spices, seasoning and stocks can all be added to the cooking liquid. However, salt should only be added once the beans are soft, because it can harden the skin of the beans and prevent the insides from cooking.
An alternative to pan boiling is to use a pressure cooker. Dry beans will still need to be soaked overnight, but the actual cooking time can be cut to five to ten minutes, depending upon the type of bean.
Microwave ovens are not suitable for cooking dry beans, because rehydration and cooking requires long slow simmering. Slow cookers or crock-pots are not suitable either, because the cooking does not reach a sufficient temperature to soften the beans properly.
A warning: All dry beans should be soaked overnight, boiled hard for 15 minutes and then simmered until soft. If these simple rules are not followed, your run the risk of food poisoning, particularly prevalent from poorly cooked red kidney beans. The beans contain a toxic agent called phytohaemagglutinin, or lectin. It causes red blood cells to clump together, resulting in nausea, vomiting and diarrhoea. Recovery is usually spontaneous, although hospitalisation is sometimes necessary. You have been warned!
Baked beans are probably the most popular form of cooked beans, ubiquitous to the canned vegetable aisles of supermarkets and possibly the favourite 'vegetable' in Britain. Baked beans are haricot beans coated in tomato sauce and sometimes supplemented with sausages, bacon or spices. They are a good source of protein and fibre and also contain potassium, iron, magnesium and manganese. The tomato sauce is also beneficial, being a source of lycopene, an anti-cancer agent5.
Beans and Flatulence
Many people are put off eating beans - particularly dry beans - because of their reputation for causing intestinal gas. The reason for flatulence is that most beans cause a sudden increase in bacterial activity in the intestine, because they contain large quantities of carbohydrates that human digestive enzymes cannot convert into absorbable sugars. As a result gas is produced a few hours after bean consumption.
The solution, or at least a partial solution, is to cook dry beans for a long time. This breaks down much of the unabsorbable carbohydrates into digestible sugars. Sprouted beans tend to be less gaseous because the carbohydrates are converted to digestible sugars during germination of the bean.
Beans are a great source of protein. They are a versatile kitchen ingredient. They are easy to grow. They are cheaper to produce or buy than meat protein products. They taste great. They look great. Become a bean fan!