Delicious black olives processed by natural salt treatment
Black Olives in Dry Salt
This is a traditional way of producing olives. Alternate layers of washed black olives and dry salt are mixed in a container containing drain holes in its base. The container is covered and left. Over a few days osmotic pressure causes the olive fluids to drain out of the olive while salt dissolves into the olive. The strong salt tends to debitter the olive and eventually equilibrium is reached with most of the olive fluid having been removed and an acceptable salt level reached. The olives are then washed free of excess salt and dried (a low heat oven is sometimes used). The olives are then often coated in olive oil, placed in jars, and perhaps refrigerated.
Scum, which accumulates on top of brine, is undesirable. It consists of yeasts and moulds. Some people regard this film as desirable but this is not so, the film or scum consists of spoilage micro-organisms. At the very least they will use up acids already produced, the loss of acid will then cause the pH to rise, possibly to a level where even more dangerous spoilage organisms are able to grow; these can possibly produce toxins which can prove fatal to humans. Always remove scum by skimming it off or adding brine to cause it to overflow from the container and then reseal it to prevent air ingress.
Vinegar addition. The combination of vinegar and alcohol produced by certain yeasts can produce ethyl acetate (the active ingredient in nail polish remover) which has an unpleasant odour and taste and will spoil the olives. Use vinegar as a flavouring agent only at the end of fermentation and always use lactic acid only during fermentation.
Spices and flavours. These are used universally to enhance the flavour of table olives and olive products. It is recommended that flavourings, herbs and spices only be added just before the olives are consumed and are not added during the fermentation or curing period.