German mustard от John Spottiswood

This is a very pungent brown root that's usually peeled and grated to make a condiment for meats. Its intense flavor and aroma dissipate quickly when exposed to air, so it should be grated just before serving or mixed with something sour (like vinegar, lemon juice, or beet juice) to lock in the heat. It's easiest to use a blender or food processor to grate it. Fresh horseradish is surprisingly potent, so make sure your kitchen is well ventilated, wear rubber gloves, and don't rub your eyes.