I always keep a jar of store-bought preserved horseradish in my fridge. In a pinch, it's a perfectly good product, whether I'm whipping up cocktail sauce for poached shrimp or sitting down to a jar of gefilte fish for a light and lovely afternoon snack—and, as lovers of gefilte fish, we all know it's fantastic with horseradish. For the very few of you in this world who don't love gefilte fish, I'm sure you at least appreciate the power of a horseradish cream sauce on a roast beef sandwich.
Even better than the jarred stuff, though, is homemade preserved horseradish. Simple as can be, all it requires is grating fresh horseradish, then soaking it in vinegar with a little salt.
The first step is grabbing some fresh horseradish, which, admittedly, can be a little tough. First, because not every grocer carries it, but also (and primarily) because it's the single most suggestive vegetable you can reach out and touch in all the edible land. I'm hard to embarrass, and even I feel an awkward twinge when I pick one of these things up. Because, I mean, c'mon:
But we're adults, and we can handle such things, right? So yeah, reach out and grab that horseradish and put it in your basket. On our way now!
Back at home, we first need to skin it. Now here comes a big warning: Horseradish can vary wildly in pungency. Milder roots are nothing to worry about, but really fresh, strong ones can seriously mess you up. A farmer friend once gave me a horseradish root straight from her soil, and I had to flee my apartment after starting to grate it because I literally couldn't breathe. I've never been attacked with mustard gas, but I have an inkling of what it's like after that experience. There's a reason these guys wear gas masks when making preserved horseradish commercially.
With that in mind (and windows WIDE open), start by trimming off the ends of the root with a knife.
Then, with a sharp peeler (I like Y-peelers best), remove the rest of the exterior.
The interior should be nice and white.
Next, cut the root into manageable pieces, and dice it into chunks from there.
Transfer it to a food processor or blender and, once again, be prepared for even more pungency: Chopping up the horseradish will release even more of its potent volatile chemicals, known as isothiocyanates, and may well send you running for fresh air.
Then process or pulse, scraping down the sides, until finely ground. If you have a high-power blender, be careful not to overprocess the horseradish, or you'll end up with a pasty mush.
The final step is to add vinegar and season with salt, but there's one little detail worth mentioning here. See, the horseradish root usually keeps its harsh isothiocyanates safely contained in its cell walls under chemical lock and key. When the cells are damaged, enzymes in the root are able to free the isothiocyanates. Think of it like a jailbreak, where the isothiocyanates are prisoners and the enzymes are an outside team tasked with freeing them. The blender or food processor (or even a metal box grater, if you want to do it manually) is like the dynamite used to blow the prison walls open. Once they're open, the more time the enzymes have to work their way through the prison and free those prisoners, the more prisoners will escape, making the air and flavor even more pungent.
So, the longer you wait to add the vinegar, the stronger the horseradish will get. Once added, though, the vinegar puts a stop to the process. That said, it really all depends on the horseradish itself—the one I was using in the photos here was mild enough that letting some of it sit for several minutes before I added the vinegar didn't change a thing. I used distilled white vinegar here.
Add salt to taste, and cut with a tablespoon or two of water if it's too strong. Mine here didn't need it, but sometimes it can help.
Then just seal it up in an airtight container and keep it chilled. It'll keep at least a few weeks, if not longer, in the refrigerator.
Try this stuff in your cocktail sauce or horseradish cream, or (most likely) on your gefilte fish, and that jar from the supermarket may end up forgotten at the back of the fridge.