Rinse horseradish root, trim the ends, and peel with a vegetable peeler, like a carrot. Chop into small cubes (1/2, or so) and put into food processor, along with salt and process on high until well ground. Add 1 or 2 Tbsp. water if not grinding well. Do in well ventilated area. Fumes can burn your eyes.

Adding the vinegar stabilizes the chemical reaction that starts when horseradish cells are broken in the grinding. It puts a stop to the growing heat, so if you like it hotter, wait 10 minutes or up to 30 minutes before adding the vinegar. For milder horseradish, add vinegar right away. Add 2 tablespoon or more to taste and pulse processor a couple more times.

If its too soupy, you can pour off a bit of the liquid before storing, but the liquid is pretty tasty.

Transfer the horseradish to small 4 oz glass jars with secure fitting lids. This will store several weeks in your refrigerator. If frozen, it will lst months. Best to freeze in small plastic deli tubs.