Piercing of cabbage during fermentation is a compulsory procedure. Without it the ready-made product will have bitterish taste. However it is necessary to carry out this work not from the first day of fermentation.
So, for what it is necessary to puncture cabbage at fermentation? Of course for release образовывающихся gases in a product. During fermentation vegetables in a bank/pan/flank are quite strongly stamped, without the additional help to gases just not to leave. Yes, it is possible not to puncture of course cabbage at all, it will pretty fast be fermented, but here only most likely the product will taste bitter. Therefore if you want to receive as a result a tasty and crunchy kapustka, then don't neglect this procedure.
As for questions when it is necessary to puncture cabbage, than it is better to do it and how often to carry out the procedure, that is certain rules. The wooden pointed stick from a birch, an aspen or other not resinous tree best of all is suitable for piercing of cabbage (it is better not to use metal objects of type of a knife as they have negative effect on fermentation processes). The first piercing should be made in the evening of the second day or in the morning of the third, here everything depends on a condition of cabbage - if on a surface of a product there is a foam already by the end of the second day, then to hesitate with piercing is unnecessary.
Once a day is the best of all to carry out the procedure, and the quantity of punctures depends on cabbage volume, but usually to five-seven happens enough. It should be noted that some hostesses carry out piercing of cabbage at its fermentation on two and more times a day, however here It should be noted that the more often these actions are made, the longer the product is made sour, and in certain cases excessive deflation of gases from cabbage can lead to souring of a product in general.