I too have made horseradish from scratch, and, if you make extra, you can give some jars away. You can tell your friends you cried real tears making their jar of horseradish sauce, because you WILL HAVE done that.
After you pull or dig up some of the roots in you horseradish patch:
1) cut off the leafy tops and any very skinny long root ends with not much to them
2) scrub all of the dirt off of the roots
3) chop up the roots to pieces small enough that they won't jam your blender (you'll figure out how small that needs to be)
4) you have already started crying by this point
5) pour some vinegar into your blender and then dump in some horseradish chunks with the object of having just enough liquid in there (vinegar not tears) for the blender to finely puree the root pieces
6) when you take the cover off of the blender you are really weeping now, a towel might come in handy
7) start filling jars with the prepared horseradish, screw on the lids and refrigerate
8) keep grating the root chunks in the vinegar in the blender and crying until it is all done
9) it could take a long time (what idiot dug up a half a bushel of horseradish roots when you only needed like a dozen good sized roots-- criminey!)
10) Finally, all the grating is done. All of the jars are filled. And your tearducts are sucked completely dry.
With this method the only preservative is the vinegar. If you really like horseradish, you can finish off even a big jar before it goes bad.
Most seed catalogs will offer starts of horseradish root. The stuff is going to keep growing a long time (decades and decades) in the area where you planted it. You do need to let it get started well, maybe a year or so, before the first harvest.