About Black Radishes:
The black radish is part of the cuisine of continental Europe, in particular of eastern Europe. However, it is not commonly used in the UK or USA. They can be used in a variety of different dishes, including soups, stir-fry or salads.
It is black on the outside (thus it's name) and has white flesh. It can either be round in shape, or it can be elongated. The skin (the black exterior) is not suitable for eating and is peeled off. The flesh itself has a firm, crisp texture (similar to turnip). When raw the texture is slightly woody, which is mildly unpleasant to eat, so it is either cooked (making it softer) or it is shredded or finely cut to remove the woody aspect.
There are two types of black radish: spring and winter. Spring radishes are grown and harvested early in the growing season, while winter radishes are grown late and harvested in the fall or winter. Most cooks prefer the winter radishes, in part because spring radishes tend to be somewhat bitter.
When buying a black radish, choose one that is firm and crisp, with an even black exterior. Avoid ones that are soft or wrinkled. They can be stored for several weeks in the refrigerator (remove their leafy tops when storing).