How to Pickle Frozen Vegetables
Pickling is primarily a way to preserve food, but if you don’t have a fertile (vegetable?) Garden, you will most likely see it as a way to make the parts of the plant spicy and tasty. This is most often done with fresh vegetables, but if the vegetable you want is out of season, you can (probably) use frozen ones.
Frozen corn, such as pickles, is great as is canned food; and pickling frozen pearl onions is even better than their fresh counterparts. Not much frozen broccoli. You see, when water freezes, it rearranges into a crystalline structure that takes up more space than its water form, effectively stretching the vegetable’s cell walls. (This is also the reason that meat becomes tender if you freeze it more than once, all of this expansion and contraction upset the cell walls.)
Pickled vegetables should be a little soft anyway, so this expansion isn’t necessarily a bad thing. When I did a side-by-side comparison of pickled onions, I found I preferred pickles made with frozen onions, as the fresh ones were still quite tough and spicy after pickling (especially in the center). Pickled corn made from frozen food was slightly softer than fresh corn, but not much, and the sweet and tangy taste was much the same. Pickled frozen mushrooms are fine too, but all canned mushrooms are inherently soft.
A good rule of thumb is to avoid frozen vegetables that can eat porridge when cooked. Frozen broccoli are a poor candidate for pickling (the fluffy part gets so wet!), As are green beans (but this can vary depending on how they’re sliced). On the other hand, frozen beets marinate well.
Once you’ve collected a few frozen plants, pickle them like any other vegetable. Place frozen vegetables in an ovenproof jar – no need to defrost. Make a pickle – I like this one – and heat it in a saucepan until the salt and sugar dissolve, then pour it over the vegetables. Wait until it cools to the touch, then refrigerate in the refrigerator overnight. Use like any other brine (apply it to everything).