Horseradish is a root, similar to wasabi, and a member of the mustard family. Prepared horseradish is grated horseradish root combined with distilled vinegar. It has almost no taste until grated when the cells are crushed to release a volatile oil that produces the “heat.”
1 7-inch (11-ounce) horseradish root
2 tablespoons water
Using a vegetable peeler, peel the horseradish root and cut into one-inch cubes.
Place the cubes in a food processor and add the water. Pulse until the horseradish is somewhat smooth. Process the horseradish, scrapping the sides of the work bowl, until it is the consistency you desire.
(Be careful not to get too close to the grated horseradish when removing the cover. This is powerful stuff and will bring tears to your eyes and clear out your sinuses!)
Allow the horseradish to bloom to the desired heat level and add enough vinegar to cover. Pulse to incorporate. Drain the horseradish through a fine strainer and transfer to a storage container.
The horseradish will keep, refrigerated, for about one month although the flavor will diminish over time. Discard the horseradish if it turns brown.
Vinegar stabilizes the degree of hotness; the longer you wait before adding the vinegar, the hotter the horseradish will be. (My recommendation is to wait at least five minutes before adding the vinegar.)