Cucumbers become pickles through a process called pickling, which has been used to preserve a wide assortment of foods since at least 2,000 BCE. Pickling ferments foods with beneficial bacteria for flavor, and also preserves them in an acidic brine solution so that they will not go bad. Pickled foods will last for up to one year when handled properly, and they can be used in a range of dishes, typically as condiments. Technically, the word “pickle” can refer to any pickled food, but in North America, most people think of cucumber pickles when pickles are under discussion.
Pickling properly requires some training, as mishandling will cause the pickled foods to go bad. A number of conditions must be met when cucumbers become pickles. Otherwise, the pickled cucumbers may be dangerous to eat, because bad bacteria may have formed. For this reason, people who intend to pickle at home should make sure that they know what they are doing. Many cooks prefer to purchase already made pickles to avoid the risk of food borne illness, and any container of pickled foods should be discarded if the lid has become convex, or if mold appears, as this indicates that it was not handled or sealed properly.
Pickling requires scrupulously clean conditions, and very fresh fruit. Ideally, the fruit should be pickled within 24 hours of harvest, and not before being carefully washed and, in the case of cucumbers, trimmed. Cucumbers become pickles in two different ways after they are processed for pickling. Cucumber pickles are also made with a special cultivar of cucumber, not regular table cucumbers. This cultivar has a consistent size and a knobbly texture which may be familiar to consumers of whole pickles.
The first way to make cucumber pickles is the classic pickling technique, which starts with a process called anaerobic fermentation. The cucumbers are entirely submerged in a brine solution made with pickling salt, which may include other whole fresh spices such as mustard seeds, cumin, or dill. Typically, the cucumbers are weighted so that they stay entirely submerged, and the brine is periodically skimmed and topped off. Once all of the pickles are completely fermented, they are soaked in several changes of fresh clean water to extract salt. If the pickles are to be sliced, the slicing is done after the fermentation is complete.
After being fermented, the pickles are stored in an acidic vinegar solution which keeps them from going bad and is the final step required in making cucumbers become pickles. Pickling vinegar has an acid content of at least 5%, and it keeps bad bacteria at bay. Some people skip the fermentation step, pickling cucumbers directly in the vinegar solution. When cucumbers become pickles, they are sealed in sterile jars which are pasteurized through the hot water canning process to keep the vegetables from going off. These jars usually keep for around a year in a cool dry place, and they should be refrigerated after opening.