Adzuki or azuki beans are small reddish-brown legumes that grow throughout Asia. They have a high natural sugar content and are popularly used in a variety of sweet dishes and desserts, though they can also be paired with spices and other vegetables to create more savory dishes. Purchasing them fresh is usually the best way to maximize their flavor, but this is often difficult outside of their natural growing area. In most parts of the world, these beans are sold either dried or as a concentrated paste.
Adzuki beans are known scientifically as Vigna angularis. They are typically quite small, ranging in size from about 0.25 to 0.5 inches (0.6 to 1.3 cm) in length. Most are a dark red or rusty color and tend to have a “seam” of white or cream running down their backs. Depending on where they are grown they might also be dark gray or brown, though these variances are rare. Adzukis have a sweet taste when raw that grows stronger as they are cooked.
Primary Growing Region
Most food researchers believe that adzuki beans are native to the foothills of the Himalayas, in what today is Nepal, Northern India, and South China. The beans feature prominently in the cuisines of these countries, but are perhaps even more popular in countries that sit farther north, particularly Korea and Japan. Farmers across Asia have found ways to grow adzuki crops, and the beans have become a staple part of many different local cuisines. It is rare to find adzukis growing outside of Asia, but the export market is robust and they can often be found in specialty shops and international grocers all over the world.
Popularity in Desserts and Sweet Dishes
Far and away the most popular use for adzuki beans is as a sweetening agent in desserts, drinks, and even ice creams. Cooks often boil the beans in sugar and water to make a rough paste that can be used as dough for different cakes and confections. Chinese “moon cakes,” which feature prominently in national celebrations of the annual Moon Festival, are one example. These cakes are light pink in color, and tend to be very intricately designed, often with the help of kitchen molds or imprint stamps.
Zongzi, sticky rice dumplings, are another Chinese festival food made with adzukis. These dumplings are traditionally filled with red bean paste are very popular during the midsummer Dragon Boat Festival. A number of traditional Chinese pastries made for everyday consumption follow a similar recipe. The beans can either be mashed into a paste or used whole, and can be either a filling or a binding agent for the dough itself.
In Japan, anmitsu is a jellied substance made from agar, a seaweed extract, and served with red bean paste as a dessert. Japanese cooks commonly also use adzuki beans to flavor ice cream, often incorporating them whole. Simmering the beans in sugar candies them, creating another popular sweet known as amanatto.
Red bean rice cakes can frequently be found in the lunchboxes of Korean schoolchildren, and sweet red bean soup is a common, if simple, meal in that country. Korean cooks are also fond of mixing cooked red beans with cream and milk to make a unique dessert drink commonly eaten with a spoon or wide-mouthed straw.
Adzuki beans need not be limited to sweet dishes and desserts. They often add an interesting counterbalance to spicy stir-fry meals, and are a common side dish to many meat and vegetable preparations. Korean cooks in particular often add them to egg-based pancakes or omelets alongside more savory elements like potatoes and chili peppers.
Tips for Preparing and Purchasing
”Purist” cooks usually recommend starting any adzuki recipe with fresh beans, but these can be hard to find outside of their primary growing region. It is much more common to purchase the beans either dried or preserved, even within Asia.
Both dried and fresh varieties will need to be cooked before they can be used in most dishes. Fresh beans cook the fastest, often needing little more than a couple of minutes in boiling water. The idea is to get a bean that is tender, but not overly soft. Getting the same results with dried beans often requires soaking, sometimes for several hours or overnight. The beans must then be boiled, as well, often for up to an hour.
It is usually possible to buy ready-to-eat adzuki either in cans or sealed plastic pouches. Most of these come surrounded by some sort of sauce or preservative which keeps the beans plump and moist. Cooks typically rinse this away, but it can usually be eaten or incorporated into recipes — though it should be noted that adding extra fluids might change the consistency of the finished product.
People who are hoping to turn their adzukis into red bean paste can save time by purchasing pre-made pastes. These, too, often contain preservatives and other ingredients designed to enhance shelf life and transportability, but are often the best choice when time is short. Making the paste from scratch usually involves a series of boiling, cooling, and pureeing. It is not complicated, but can take awhile.
Adzuki beans are generally considered quite healthful. They contain virtually no fat or cholesterol, and are a good source of dietary fiber and protein. Though they are high in natural sugars, they rich in a range of other helpful minerals, particularly iron and calcium.