The food preservation technique we call pickling has been practiced in some form or another for thousands of years. Soft-skinned vegetables such as cucumbers, cabbages, beets and peppers are placed in a special brining solution containing vinegar, salt, water, various peppercorns and spices. After several hours, days or even weeks spent in this salt water bath, much of the vegetable's natural juices have been replaced with an acidic brine that naturally discourages harmful bacterial growth. Most pickles do not require refrigeration because of this natural acidity.
When most of us hear the word "pickles," we immediately think of cucumbers, which are by far the most common vegetables used. Other fruits and vegetables can be brined, but only cucumbers are marketed as pickles. Not all cucumbers are used, however; the larger American cucumber variety commonly found in salads does not usually do well during the pickling process. Instead, smaller varieties are grown specifically to become one of the many of types found on grocery shelves.
One of the most popular type of pickles are called dills or kosher dills. The brine used to create a dill uses a substantial amount of the dill weed herb, plus a significant amount of garlic. The resulting pickles are commonly found stored in large barrels and served as a side dish with deli sandwiches. Whole ones are crunchy, with a strong hint of garlic and a slightly sour dill weed bite. Sliced versions are commonly placed on hamburgers as a sharp counterpoint to the hearty meat flavor. Smaller ones, called gherkins, may serve as snacks or condiments on a party tray. Dill pickles may also be chopped into a form of relish.
Another variety commonly found in grocery stores is called sweet pickles. This type is brined in a solution containing more sugar and less garlic. Smaller cucumbers and gherkins are often used to make them. They are rarely offered as side dishes in delis and restaurants because of their intense flavor. Sweet pickles are more commonly used in cold salads and relishes.
Alongside the sweet and dill, you may find bread and butter pickles. Bread and butter types are not quite as sweet as sweet pickles, but they do not have the same sour bite as dill. Many people prefer the taste of this variety on sandwiches or cold salads. It is rare to find a whole ones — they are more likely to be offered in slices or relish cubes.
Many home cooks prefer to make their own from organic cucumbers and home recipes. One example of this is called a 14 day pickle, a name referencing the amount of time spent in the brining process. It can be very sweet, with overtones of both the traditional sweet and the bread and butter varieties.
There are also specialty pickles for those who enjoy an exotic flavor. Greek peppers called pepperoncinis are often pickled and served as a spicy condiment on sandwiches, pizzas and salads. Mixtures of dills, pearl onions, jalapeños and cauliflower florettes may be brined in a very spicy solution to yield hot mixed pickles. Various fruits may also be pickled in a sweet brine and served year round. Some people even use watermelon rinds. Beets are routinely pickled, as is cabbage to form sauerkraut.