The ancient practice of pickling preserves asparagus so this short-season spring vegetable can be enjoyed year-round. Asparagus stalks adopt a sour, salty flavor from the vinegar and salt in the pickling brine, making it a suitable alternative to cucumber pickles on cold cuts and on relish trays. Turn to pickling when your garden produces more asparagus than your family can eat and you want a shelf-stable preservation alternative to freezing asparagus.
Thin, young asparagus stalks have the best flavor and texture for pickling, just as they are preferred for other preparation methods. Older asparagus stalks left to grow develop a tough, woody base that is difficult to chew and lacks flavor. As a guideline, look for asparagus stalks that are thicker than a pencil but narrower than your index finger. Wash the asparagus well to remove any sand or dirt from the stalks, particular near the tip. Bend the spears to snap off the woody base or cut them off with a knife. Tougher asparagus spears can be blanched before pickling to tenderize them. Trim the asparagus as needed so all spears are roughly the same height and short enough to fit inside the canning jars.
Quick Vinegar Pickling
Vinegar pickling offers the quickest and easiest method for pickling asparagus. Wash canning jars with the hottest water possible. Pack each jar tightly with asparagus spears standing upright. Add garlic cloves, fresh dill, hot peppers, and spices such as coriander, mustard seeds, peppercorns, cardamom pods and bay leaves for extra flavor as desired. These ingredients can go underneath or on top of the asparagus. Boil pickling salt and equal parts water and distilled white vinegar in a saucepan. To pack seven 12-ounce jars, use roughly 1/3 cup pickling salt and 3 cups each of water and vinegar. Pour the hot mixture over the asparagus, leaving 1/2 inch of head space to the top of the jars. Tap the jars on the counter to remove air bubbles, wipe the rims clean, and place a metal canning lid and band on each jar.
The hot water bath canning method sufficiently preserves pickled asparagus. Place the jars in a large canning pot with at least 4 inches of boiling water. Boil the jars for 10 to 20 minutes to seal the jars. Process the jars for 10 minutes at elevations below 1,000 feet, for 15 minutes at elevations between 1,001 feet and 6,000 feet, or 20 minutes for elevations above 6,000 feet. Remove the jars from the hot water carefully to avoid knocking them into anything and breaking the glass. A specialty canning tool called a jar grabber works well for lifting the jars without burning your hands.
Storing Pickled Asparagus
The jars of pickled asparagus must rest at room temperature undisturbed for 12 to 24 hours to cool. After this cooling period, remove the metal bands and press on the center of each lid to ensure the jars are sealed. If the lid is not sucked down tight against the jar rim and you hear a pop when you press the lid, the seal did not take. Keep improperly sealed jars refrigerated and consume within 1 week to prevent spoiling. Pickled asparagus should be kept in the jars undisturbed for at least 1 day before eating so the pickling brine has enough time to actually pickle the vegetables, but best flavor is achieved with a wait time of three to five days. Store the pickled asparagus in a cool, dry place for up to 12 months. Store jars in the refrigerator after opening and eat within 1 to 2 weeks.
Lactic acid fermentation, or lactofermentation, offers another pickling option for preserving asparagus, but this more complicated process is better suited for serious pickling enthusiasts. This is the same process used to ferment homemade sauerkraut. This no-vinegar-required process takes advantage of lactic acid to ferment and preserve the asparagus. Add the asparagus to a crock or jar and cover it with a brine mixed at a ratio of 1 tablespoon of salt for 2 cups of water. Make enough brine to completely cover the asparagus and add your choice of pickling spices -- garlic, peppers, peppercorns, and mustard seeds are common choices. Cover the jar or crock with cheesecloth and leave at room temperature to ferment for up to three weeks before eating.