Before you begin to pickle, consider what type of pickled product you would like to make. Many recipes are available for fresh or quick pickles, some old family recipes, and others found on the internet, or in canning books. The best practice is to use tested recipes that are available from the National Center for Home Food Preservation, USDA, or Nebraska Extension.
Fermented Pickles
Fermented pickles, including sauerkraut, are made from cucumbers or cabbage that are fermented and cured for several weeks. This process produces pickles by encouraging microorganisms to grow in foods, by fermenting them in a 2-3% saltwater solution for several weeks. Bacteria that are naturally present on these vegetables produce lactic acid under the proper conditions. The amount of salt should never be altered when making pickles or sauerkraut by the fermentation process. A special flavor results when pickles are made by this method.
There are many products that can be produced by fermentation, but only those for which recipes have been developed for processing in a boiling water canner will produce a shelf-stable product. For example, currently, there is no home canning recommendation for kimchi or kombucha.
Fresh-Pack or Quick Pickles
Fresh pack or quick process pickles are made by adding acetic acid (vinegar) to lower the pH of the food. Spices, salt, and sugar are added for flavor. It is important to use vinegar with an acidity level of 5% or more, to ensure the safety of the product. Never reduce the amount of vinegar in the approved recipe. These pickles do not require a fermentation period and they are usually made and processed within a day. The major flavor of a fresh pack or quick pickle is due to the vinegar.
Sources:
Crispy Pickles, June 25, 2019, Penn State Extension
Food Preservation: Making Pickled Products (FN 1989, Revised Aug. 2019) North Dakota State University.
Fundamentals of Consumer Food Safety and Preservation: Master Handbook, 2015, Washington State University
Guide 6 Preparing and Canning Fermented Foods and Pickled Vegetables, Complete Guide to Home Canning, United States Department of Agriculture (USDA)