Horseradish is native to regions along the Caspian Sea from Russia to Finland, and is now grown in northern parts of both Europe and the United States. The volatile oil that gives horseradish its bite evaporates while cooking, reducing its pungency. This is why you usually find horseradish called for in uncooked sauces.
To make horseradish sauce, mix 1 part powder with 2 parts water, using more or less water for desired thickness. For mustard, mix together equal parts powdered horseradish, mustard powder and vinegar. For cocktail sauce, simply mix 2 tbsp. powder with 1 cup ketchup. It’s a zesty addition to dips, sour cream, tomato juice and Bloody Marys.