Do I need to store this in the freezer - and if so, what is the shelflife while there? The recipes I've seen talk about using half a gram of this stuff - and you sell it in 25g sachets.
According to the manufacturer as the culture is prepared in a 'clean' environment once opened it has been exposed to the outside air and as such it's effectiveness cannot be guaranteed they recommend then that any unused culture is discarded.
I can't give any advice apart from the fact that I do use just the amount I require and refreeze the rest!