The daikon radish is a very large, pale radish native to Japan and other parts of Asia. In fact, when translated from Japanese, the word daikon literally means “large root.” These veggies can grow to about 3 feet (about 72 cm) long if harvested late. They contain very concentrated amounts of vitamin C and have a spicy yet sweet flavor. For these reasons, they’re extremely popular in Asian soups. When making daikon soup, it is important to understand how to choose a good daikon, how to use the different parts of the root, and what ingredients pair well with it.
Daikon soup typically starts with the selection of one or two daikon radishes. The roots should be free of wrinkles, cracks, or blemishes. They should be very firm and feel heavy in the hand. Most daikon found in the United States and Europe are about 1 foot (about 24 cm) long and just under 2 inches (about 4 cm) thick. They resemble a very large, pale carrot and should smell slightly sweet and a little peppery. Cooks may purchase them up to a month in advance since they usually stay fresh in a refrigerator for up to a month.
The next step to making daikon soup involves understanding how to use the different parts of the root. Cooks should cut the daikon in half widthwise, separating the bulbous top from the tapered bottom. The top half of most daikon is sweeter and the bottom half is typically more peppery. The cook should chop up the bottom half and set it to simmer in chicken stock with other vegetables and a few spices. The thicker top half may be reserved and julienned. These thin pieces of the root usually make a delicious garnish for the finished soup.
Part of making a good daikon soup involves understanding what flavors pair well with this root. Carrots, ginger, chili peppers, mushrooms, onions, and chives are all usually tasty options. Chicken may also be gently simmered in the broth with the daikon and other veggies. Usually, the root vegetables, such as the daikon, carrots and onions, are simmered in a little chicken stock first. The chicken and ginger are usually added next, and the mushrooms and chives are dropped in when the rest of the ingredients are almost cooked through.
A cook need not use all of the above ingredients, some may be substituted or left out entirely. Generally other root veggies, like fennel or parsnips, also work well in daikon soup. Many cooks also add a spoonful or two of miso paste to give the soup extra flavor and nutrition.