When adding the vinegar to the grated horseradish, be careful of the pungent fumes, open a window! It’s a bold complement to mild-flavored meats and seafood (and an ingredient in cocktail sauce ). Store: Store Horseradish Sauce n an airtight container, like a glass jar, for up to 2 weeks in the refrigerator. Number of Servings: 8. Scalloped Potatoes. I made this about six months ago, and it is still very good and strong. HOW TO STORE HORSERADISH SAUCE. Grate horseradish, cover with white vinegar, add a little sugar, store in glass jars in'fridge. Ingredients: 4 Lb. Beef brisket or beef roast 1 Pack Onion soup mix ½ C. Ketchup ¼ C. Prepared horseradish 2 Sliced Onions 2 Cloves Crushed garlic Serve: Horseradish Sauce can be at room temperature for up to 2 hours, but it’s best to keep it chilled since there is dairy.It is best served at least 4 hours after making, the longer the better the flavor. Wasabi is a variation of horseradish and is made nearly the same way. Horseradish is a root vegetable with a spicy flavor and a pungent aroma.