Preserving asparagus
the two best ways
I love asparagus, and its season is short, so my desire to preserve it in some way is strong. The typical traditional ways are freezing and canning, but both, in my opinion, produce an inferior end result. Both methods utterly destroy its texture, which is probably fine if you’re going to turn it into cream of asparagus soup, and canning it destroys some of its fine flavor as well, though less so, perhaps, if you pickle it. Vinegar-pickled asparagus is often very good, and it can save some of the crunch and flavor of fresh asparagus, so it can be worth doing if you truly have a lot of asparagus to put up.
However, my two favorite ways of preserving asparagus are two that I’ve rarely heard anyone talk about: fermenting it and preserving it in olive oil. When I ferment it, I find it still tastes of asparagus and also retains a nice firm texture (though not its lovely color), and asparagus preserved in olive oil is such a useful thing as a side dish and as an addition to winter salads, pastas, omelets, and nearly anywhere else you’d like asparagus. It stays quite firm and flavorful until the next spring when fresh asparagus is available again. I’ll include the technique for each of these in this post.
Asparagus in olive oil
Adapted from Preserving Italy by Domenica Marchetti
Makes four pints. Recipe can be halved or doubled easily.
Asparagus is a low-acid food and therefore needs special care when preserving. Here, olive oil preserves by inhibiting oxygen from spoiling asparagus. Olive oil will not, however, ward off bacteria, and, indeed, the anaerobic environment is where botulism likes to grow. To kill any bacteria present on the asparagus before submerging in olive oil, you briefly pickle the asparagus. The final product is not canned but stored in the refrigerator, as a cool place will also inhibit bacterial growth.
The oil will congeal under refrigeration, so I generally bring this up to room temperature, remove the amount of asparagus we plan to eat from the oil, and then put it back in the refrigerator.
4 lbs asparagus, woody bits trimmed
2 cups white wine vinegar or rice wine vinegar
2 cups water
2 tsp salt
1 tsp peppercorns
4 wide strips lemon zest (technically optional, but recommended)
A bay leaf for each jar (optional, but recommended)
4 cups olive oil, roughly
Pinch red pepper flakes
(It is recommended by professional food scientists that you sterilize your jars and hold them in hot water until you’re ready to put the asparagus in. I do not do this. #YOLO baby.)
You may either chop the asparagus into one-inch sections (or so) or leave them long. I usually cut them into one-inch lengths, but if you prefer to leave them long, make sure they are at least short enough to fit into your jars with enough headspace for olive oil to completely cover them. Rinse the trimmed spears and set them aside in a shallow baking dish.
Add the vinegar, water, salt, and spices (including lemon zest and bay leaf) to a medium saucepan and bring to a boil over high heat. Add the asparagus and cook until tender, about 2-3 minutes. The asparagus will turn an olive green and the tips will turn an enchanting reddish color.
Hot tip: I usually use half the amounts of vinegar and water called for and cook the asparagus in batches. Even with the full amounts of liquids, I often find it more convenient to cook the asparagus in batches. Just lift the spears out with tongs to leave the hot liquid behind!
Let the asparagus cool on a clean kitchen towel until they are dry to the touch. Pack the pickled spears tightly into the jars. If you left your spears long, it helps to turn the jar on its side while adding the asparagus. When the jar is nearly full, add a bay leaf and strip of lemon zest from your vinegar solution to each jar, if you using either of those. Press the asparagus together as firmly as possible without smashing them and pack the jar completely.
Heat the olive oil gently with a pinch of red pepper flakes until it’s just warm. Pour over the asparagus in the jars, taking care to cover the asparagus completely. Let the jars sit at room temperature for 24 to 48 hours. Check to make sure the asparagus remains completely covered; if not, add additional oil (you do not need to heat this additional oil).
Place in the fridge to cure for at least two weeks before eating. The food scientists say this will last about 3 months, but we lost a jar of it in the back of the fridge one year and ate it over a year later and it was still good, if somewhat less firm. Just make sure you top the jar up with olive oil if at any point you notice the asparagus is not fully submerged.
Fermented asparagus
1 pound or so asparagus spears, trimmed of woody ends
Some cloves of garlic, depending on your taste (I like about 5 cloves per quart jar)
1 1/2 T pickling or sea salt, not iodized
2 cups filtered or non-chlorinated water
bay leaf and/or strips of lemon peel
Fill a quart mason jar with the asparagus, then push the garlic cloves, bay leaf, and strip of lemon peel into the jar.
Mix the water and salt to make a brine and pour over the asparagus, making sure to cover it. You may need to make a little more brine at a ratio of 3/4 Tbsp salt to 1 cup water in order to fill the jar.
It’s helpful to weigh the asparagus down to make sure it stays submerged, especially if you’re using a wide-mouth mason jar. If you don’t have weights for this purpose, you can fill a ziploc bag with brine and push it down on top of the asparagus until it forms a weight and seals out air. You can also use your strips of lemon peel to hold the asparagus down, maybe, sometimes this works, by criss-crossing them on top of the asparagus, under the brine, under the shoulder of the mason jar, especially if it’s a regular-mouth jar.
Cover the jar with a clean towel and secure with a rubber band (you can use an airlock system if you have one, but it's not necessary).
Set in a cool and dark place for about a week to ferment. You can go up to a week longer if you would prefer them more sour, but we like to stop it at about a week.
Cover with a lid and store in the refrigerator. If you make sure the vegetables stay covered with the brine, these will last all winter.