1. Scrub beets and trim stems to 1/2 inch. Place beets in a medium saucepan and add water to cover by 1 inch. Bring to a boil over high heat. Reduce heat to medium high and cook at a gentle boil until beets are tender when pierced with a small, sharp knife, about 45 minutes. Remove heat, drain, and set beets aside until cook enough to handle.

2. Meanwhile, grate horseradish on the medium-size holes of a box grater. Place horseradish in a small bowl and stir in vinegar, salt, and sugar.

3. Peel beets and grate on the medium-size holes of the box grater. Add to horseradish mixture, stirring well to combine. Keep covered to preserve flavor and refrigerate until needed.