Originally created to can and store excess produce from the garden and provide vegetables in winter, pickles are now a common addition to summer picnics and cookouts.
Pickles made by immersing pickling cucumbers, a specific variety, in a brine (salt) solution, which results in several transformations, first by osmosis. In osmosis, a substance passes through a membrane from an area of higher concentration to an area of lower concentration. Because of the salt in the brine solution outside the cucumber, water inside the cucumber’s cells is at a higher concentration than water outside the cucumber’s cells in the brine solution; so water moves out of the cucumber, transforming it to a smaller, crunchier vegetable.
The brine solution also specifically encourages the growth of Lactobacillus plantarum bacteria, which turn the vegetable’s sugars into lactic acid, which creates the pickle’s characteristic sour tang. This process retards the growth of microorganisms, which would otherwise lead to spoilage. When making pickles at home, it is important to obtain “pickling cucumbers,” which unlike regular cucumbers have not been treated to remove the Lactobacillus plantarum bacteria.
In addition to making a tasty snack, pickles played a small role in Christopher Columbus’ discovery of the New World. In those days, one of the greatest hazards of long ocean voyages was scurvy, caused by a deficiency of Vitamin C when the crew and passengers of a ship were unable to consume fresh fruits and vegetables. Because the Nina, the Pinta, and the Santa Maria were all provisioned with pickles, the crew remained healthy and they survived to tell of their discovery.
But pickles are not only made with cucumbers. Most culinary traditions the world over have some kind of ‘pickle,’ using a wide range of vegetables, including cabbage, jalapeno peppers, ginger, carrots, beets, and onions.
More information about pickle chemistry and history may be found at http://www.exploratorium.edu/cooking/pickles/history.html