Horseradish is an herb in the mustard family cultivated for the powerful punch of its root.
Grating or grinding horseradish releases the oils that give it its hot, pungent flavor. Wash it and peel the outer skin off the root to use the interior white flesh. Vinegar neutralizes the reaction caused by grating and preserves the heat and flavor of prepared horseradish. If not mixed with vinegar, grated or ground horseradish will darken and become bitter.
To retain the best flavor, store your horseradish root sealed in a jar in the fridge. It will last about four months stored like this. In the freezer it should last six months.
Once prepared, horseradish will stay fresh and potent for about a month to six weeks in the fridge.