When a cucumber is placed in a strong salt solution, the resulting pickles are shriveled. This is because the cucumber tends to lose water when placed in such an environment. Fermentation still occurs, though at a rather slow rate. Therefore, when pickling, it is important to use the right concentration of salt solution to get the desired fermented product.
Two processes occur during the pickling process. They are osmosis and diffusion. Osmosis is responsible for the moving out of the water from the cucumber as water molecules go to the environment of greater solute concentration. After attaining equilibrium, fermentation sets in as the salt molecules move across the cucumber cell membrane through diffusion. The rate of fermentation depends on the concentration of the brine solution. Fermentation occurs rapidly with a weaker salt solution and occurs very slowly with a stronger salt solution.
To make perfect pickles, be sure to follow the recipe and to use the right amounts of salt. Use pure salt, preferably 99 percent sodium chloride, which is often referred to as granulated salt, meat curing salt or barrel salt in the grocery store. Some salts are labeled as canning and pickling salt. Don't use waxed cucumber, as the wax prevents the salt from penetrating the cucumber.