In the past people canned and pickled their foods to extend the bounty of the seasons. These days we can get fresh produce year round, Then there’s the fact that pickling adds another dimension of flavour, a nice acidity that goes particularly well with smoked fish, pork, pâté and other fatty foods. In the Nordic countries the most common pickling principle is 1–2–3: that is, one part white vinegar, two parts sugar, and three parts water. But you can easily swap white vinegar for other types of vinegar, and water for a different liquid to add flavour and variation—try soy sauce or beer.
For hard root vegetables and larger vegetable pieces, you should ideally use a warm pickling liquid. Not only does this make them softer, but it also opens up the cells, allowing better absorption of the liquid. Soft vegetables, however, should be pickled raw and in cold pickling liquid. For an extra kick, you can add spices to the liquid. Mustard seeds and coriander seeds are a great place to start.
Pickles should be stored cold, ideally in the refrigerator. And be careful not to stick your fingers into the jar as that’s a sure-fire way of shortening the shelf life. If you take care to store your pickles properly, they’ll keep for a long time. That said, I find that over time the vinegar can dilute the flavour of the vegetables themselves, how fast that happens depends on what you’ve pickled—pickled onion is best in the first two or three days after pickling, while gari keeps for months.