Most people only know capers as the piquant little green orbs that come out of a jar and flavor many Mediterranean dishes. But if you live in a relatively mild climate where the caper plant (Capparis spinosa) grows, chances are it's a prolific weed in your area. And it's super easy to make your own capers (if you don't live in a Mediterranean climate, try this version of homemade capers instead).
The familiar store-bought version of capers is usually made from the young, unopened flower buds of the caper plant, but sometimes from the oblong immature fruits. Gather the buds or fruits while they are still small and firm. The buds may have some purplish coloration: this disappears during the pickling process.
As the species name spinosa suggests, the plants are thorny and therefore picking capers can be a scratchy, time-consuming process. But the tasty results are well worth it!
Step One - Soak the Capers
Before they are pickled, caper buds and fruits have a funky, unpleasantly astringent flavor. This first step softens that. Simply put the capers in a jar and cover them with water. Secure the lid and leave them at room temperature for 24 hours. Every day for three days, drain off the water in a colander or strainer, return the capers to the jar, and cover them with fresh water.
Step Two - Pickle the Capers
There are two ways to pickle caper buds or fruits: You can put them into a vinegar and salt brine, or you can lacto-ferment them.
To make the brine, combine equal parts white wine or apple cider vinegar and water. Add 1 tablespoon of non-iodized salt per cup of liquid (I know this sounds like a lot of salt but that saltiness is part of the flavor profile of cured capers. You can soak the capers in water before using them to reduce the saltiness).
Bring the brine to a boil over medium-high heat, stirring to dissolve the salt. Remove from the heat and let cool for 30 minutes. Pour the cooled brine over the capers in a clean jar, secure the lid, and store the jar in the refrigerator. The capers will be ready to use in one week but will be even better if you can bring yourself to wait a full month before sampling.
To lacto-ferment capers, dissolve 1 tablespoon kosher or other non-iodized salt in a pint of filtered or non-chlorinated water (Most municipal tap water is chlorinated to destroy bacteria, but for lacto-fermentation you are counting on beneficial probiotic bacteria to ferment the food.) Put the capers in a clean glass jar and cover them with the salt and water brine. Loosely cover the jar and place it on a small plate to catch the overflow that may occur as the capers ferment.
Leave the jar of capers out at room temperature for 3 days. By this time they should start to have the lightly sour but clean smell typical of a young fermentation (think sauerkraut).
Transfer the capers to the refrigerator, and wait at least 2 weeks before sampling. It is not necessary to keep the dish under the jar once you've moved the capers into the refrigerator.