In my experience it is simply necessary to prevent oxygen to get back into you jar, as oxygen is what is needed for mold to develop.
In regards to pressure recommendations, I am not of much help, I like to use old preserving jars with a rubber band between jar and lid, that allowes pressure to get out without oxygen getting in.
In my experience it is simply necessary to prevent oxygen to get back into you jar, as oxygen is what is needed for mold to develop. In regards to pressure recommendations, I am not of much help, I like to use old preserving jars with a rubber band between jar and lid, that allowes pressure to get out without oxygen getting in.