A white radish is an Asian vegetable better known as daikon, lo bak, mooli and Chinese, Korean or Japanese radish, among other names. The term “white radish” covers several varieties. No matter which type you are choosing, the criteria that help you choose the best white radish are the same for all except size. Color, firmness, cleanliness and weight are more important.
Most white radishes are oblong, except for regional varieties like the Sakurajima daikon, which is shaped like a very large, bulbous turnip. Sakurajima daikon, however, isn’t readily available outside Japan. The Chinese and Japanese varieties grow up to 20 inches (50.8 cm) long, and Korean radishes are much shorter, usually growing to a little over eight inches (20.3 cm). When choosing white radishes, look for one that is at least six inches (15.2 cm) long if it is Chinese or Japanese, or at least four inches (10.2 cm) long if it is a Korean radish. The exception is the “China Rose” cultivar of Chinese white radish, which is among the shortest Chinese white radishes at four inches (10.2 cm) long.
Diameter is not terribly important when choosing the radish, although you do not want the radish to be too thin. Radish varieties are usually at least two inches (5.1 cm) in diameter for most of their length, and many become quite plump. Depending on the cultivar, the radish could have essentially the same diameter until just toward its tip, or it could be wider toward the leaf end. If the radish does have a taper shape, it should get smaller relatively evenly as you look toward the tip, rather than having sudden drop-offs in width. White radishes should be fairly heavy.
The outside of the white radish should be clean and in good condition. While the surface can have some ridges and occasional small hairlike roots sticking out of the sides, much like carrots have, it should be overall very smooth. There should be no mold, cracks, puncture wounds, scrapes or divots on the surface. If the very thinnest end of the root is still attached at the tip, it shouldn’t be moldy. It may be dirty or broken from handling and storage, but this is fine as long as the main portion of the root is in good condition.
The best color for a white radish is white, of course, but some varieties will be brighter than others, and the white should look clean and not sickly. The top layer of the root will have a bit of a sheen. Many white radish cultivars have a greenish neck or cap at the leaf end of the root, and on Korean radishes, this green portion can extend nearly halfway down toward the tip. This section is edible, though as with those radishes that don’t have the green portion, you’ll have to peel the top layer off when preparing the radish.
Grocery stores in countries like the United States may sell white radishes either whole or cut into segments, and these are not always limited to just the thicker portions of the root. Some of the segments you find may be thin because they are from the tip end of the root. In this case, look at the color and condition of the segment to choose the best one. Whole radishes may still have their greens attached, or they can be trimmed off before sale. Greens in good condition will not be rubbery or wilted. Storage and transportation of the radishes can crush the greens, so unless you are planning to eat them as well, don’t let crushed leaves stop you from buying an otherwise good radish.
Should you find a whole white radish with crushed greens, don’t remove the greens from the rest of the radish and leave them behind in the vegetable bin without asking a store manager first. Sometimes stores in countries like the United States pay for all of the radish when buying it from a farm, including the greens. The cost you pay for the weight of the greens goes to make up for that initial outlay.