Pickling can only be used for foods that will be used pickled. Once you have pickled something, you cannot substitute it for a fresh ingredient in a recipe.
There are many ways to 'pickle' cucumbers and vegatables. The most common recipes for pickling involve vinegar (distilled or apple cider vinegar) and salt. Both distilled and apple cider vinegar contain acetic acid. So your answer is 'acid.'
Acid pickling means pickle the acid.
pickling
Pickling alters the taste of foods permanently by soaking them in a solution that changes their flavor but allows them to be preserved for a longer period of time. Pickling can only be used for foods that will be used pickled. Once you have pickled something, you cannot substitute it for a fresh ingredient in a recipe.
Vinegar is the main ingredient some add water, the others are the spices which very such as sugar, salt, dill, garlic, onion, and cloves.
Certain varieties of cucumbers have been bred specifically for use in pickling. By using these varieties, the home pickling enthusiast will end up with a crisper and more flavorful result. If growing cucumbers at home, be sure to select seeds that are labeled as "pickling" or "good for pickling" on the seed packet. Good choices for pickling cucumbers include: Pioneer, National Pickling, Saladin, Bush Pickling Liberty Hybrid, Ballerina, Boston Pickling, and Eureka Hybrid.
Pickling lime used to be an accepted method of adding crispness to pickled cucumbers. The USDA no longer recommends use of pickling lime. Pickling lime is alkaline and must all be washed off of the cucumbers or it can result in a less acidic pickling solution. It the pickling solution is not acidic enough it can allow botulism an environment in which to grow. Botulism cases have been linked to this situation and this is the reason it is no longer recommended.
Microorganisms are not a good thing when it comes to pickling. Generally you want to kill off microorganisms when pickling.
The process is usually referred to as pickling, or descaling.
Because the acid in the pickling liquor reacts with the aluminum and spoils the pickles.
The addition of vinegar and the processing times are different for pickling than for canning. Canning cooks the vegetables thoroughly whereas pickling is done from the veggie's raw state.