Horseradish is a member of the mustard family and is native to Eastern Europe, although it may have originated in Asia, Germany, or the Mediteranean area. The ancient Greeks used it, so did the Hebrews — it is one of the 5 bitter herbs of the Jewish Passover. The strong flavor of this root has an underlying sweetness and seems more like garlic than a spice.
Horseradish roots are available year round but are plentiful during the fall and early spring. Buy roots that are hard. Avoid sprouting, greenish tinges, blemishes, and shriveling.
Store these roots in plastic bags and refrigerate up to a week or freeze grated root in an airtight container for several months. Scrub the root and peel the brown skin. Finely grate or food process the root.