The one thing you want to be sure to do when preparing the horseradish is to have adequate ventilation so the fumes do not hurt your eyes or keep you from breathing. The chemical in horseradish that causes the irritation is allyl isothiocyanate.
Be certain to let the horseradish rest for ten minutes after it is ground and prior to adding any liquid. That will maximize the heat level, which is exactly what you want to do. Basically, an enzyme present in the horseradish weakens the cell structures allowing the allyl isothiocyanate to be released. Then, Wow!
Some recipes for making prepared horseradish call for the use of a small amount of sugar to "round out" (or make smoother) the flavor. That addition is optional. I suggest trying the sugar addition in half of what you make and then taste test both versions to decide what you prefer.
Try to use the prepared horseradish you make within one month as the product becomes more mild through time. You might also share some of what you make with friends or relatives, and they will be most appreciative.
Ingredients: (makes 3 cups of prepared horseradish)
1 pound of fresh horseradish root
½ cup of white vinegar (5% acidity)
1 cup of cold water, plus a bit more if needed
1 teaspoon of kosher salt, or to taste
1/2 teaspoon of white sugar (optional)
Directions:
Peel the horseradish root and cut out any dark veins. Open any nearby windows to get air flow where you are working so you can breathe normally, and if necessary use safety glasses to protect your eyes from strong fumes.
There are different ways to process peeled horseradish root to arrive at a finely ground but not mushy state. Three different methods are described next.
Using a box grater and doing the work by hand produces a nice grinding result but comparatively with a lot of manual labor and exposure to fumes. If you use that method, let the ground horseradish rest for ten minutes and then mix it in a bowl with the other ingredients.
Another nicer method is to use a powered vegetable shredder, followed by a ten minute resting period, then putting all ingredients into a blender and blending until the desired fineness of the pieces is met.
A third method is to cut the peeled root into 1/2" by 1/2" chunks and use a food processor for the initial grinding, then allow the ten minute rest period, then add the remaining ingredients and process the mixture briefly.
Transfer the prepared horseradish to a quart-size canning jar or into two or three smaller canning jars. But do not heat the prepared horseradish in any way as that will destroy the taste and strength.
Seal the jar(s) and refrigerate the horseradish until you serve it.
The prepared horseradish will last up to 3 months in the refrigerator.
Enjoy! And I know you will!