Horseradish is a very powerful and pungent spice similar to the related species wasabi and mustard. The intact horseradish root has virtually no aroma.
When cut or grated, enzymes from the broken plant cells produce a strong mustard oil. Once exposed to the air, though grating or chopping or heat the grated horseradish darkens, loses its mustard aroma and assumes an unpleasantly bitter taste.
The original taste can be preserved by adding vinegar, and so horseradish is mostly made into white to cream colored sauce.
Horseradish sauce is popular in many countries especially with roast beef, cured ham and other meats, but it can be used in a variety of other dishes such as sandwiches and salads.
One popular variation is to replace the vinegar with lemon juice or citric acid. The pungent mustard oil is not heat resistant, and so horseradish is mostly used with cold or warm food (added immediately before serving).
This article provides a set of fabulous Horseradish Sauce Recipes and tips for other uses.
Places all the ingredients, apart from the vinegar, in a blender. Add about one quarter of the vinegar and start blending. Slowly add more vinegar while blending until mixture reaches the consistency you want. Don't over blend the mixture - it should have a chunky consistency. The sauce can be stored in a glass jar in the refrigerator.
Grate the horseradish, and combine well with the salt, pepper, sugar and mustard. Slowly add enough vinegar to give the sauce the consistency of cream. Add the cream if desired.
Combine all ingredients in a mixing bowl and mix until smooth and creamy. You can use fresh lemon juice to replace some or all of the vinegar.
Whisk the sour cream lightly. Add the remaining ingredients. Taste and adjust the seasonings to taste. Always grate the horseradish just before adding to the mixture. You can store the sauce in the refrigerate for 1-2 days.