Savor the hot, spicy zing of horseradish without worrying about it spoiling by drying the fresh root and grinding it into a powder. Add the homemade horseradish powder to homemade spice blends for a pop of flavor and heat, use it as a dry rub for steaks or roasts, or rehydrate dried horseradish powder by using it in sauces or dressings.

Because jarred horseradish — the kind that you usually see in the grocery store — typically contains additives such as salt and vinegar, start with a fresh horseradish root for optimal results with pure horseradish flavor. Select a mature, firm root. Scrub the outside of the root with a vegetable brush and rinse the horseradish under running water. Trim the top from the root and slice it into 1/4-inch pieces or grate it using a box grater or a food processor.

As a general rule, Deanna DeLong, author of How to Dry Foods, recommends drying horseradish at 150 degrees F for one hour, and then at 130 degrees F until the horseradish is dry and brittle. Some methods that you can use include:

  • using a dehydrator, which is one of the easiest and most energy efficient ways to dry horseradish. Most dehydrators feature adjustable temperature controls and a built in fan to speed the process. Start the horseradish at 150 F, then lower the temperature to 130 F for another five to nine hours.
  • oven-dehydrating horseradish, which requires no special equipment. If your oven doesn’t go as low as 130 F, set it to the lowest possible setting and crack the door to maintain lower temperatures. Place a thermometer in the oven to monitor the heat. Arrange the horseradish on baking sheets lined with parchment paper and check it often for doneness, especially if you’re drying it at a higher temperature, which takes less time.
  • drying horseradish outside, which is best done on a dry, sunny day that’s 85 F or warmer. Arrange the horseradish on a slatted tray or wire racks. Place it directly in the sun and allow it to dry in the sunlight, flipping the slices occasionally for even drying. Drying times vary widely depending on air circulation and humidity levels, but typically average four to 10 hours.

Tips

No matter which method you choose, dry the horseradish in a well ventilated area to avoid potential irritation from its strong, pungent smell.

Once the horseradish is dry and brittle, you know you’ve removed most of the moisture. Allow the horseradish to cool before transferring it to a blender or a food processor. Pulse or blend the dried horseradish until it’s ground into a powder. Store it in an airtight container in a cool, dark spot. According to the University of Minnesota Extension, dried horseradish keeps longer than fresh — which keeps for several weeks — but it may lose its bite as time goes by.