Malting is the process by which the grain is soaked over a few days and then laid out to dry. Once it starts to germinate, it is very roughly crushed or ground so that the husks are just starting to break away from the grains. This ensures that as much as possible of the food contained is available for fermenting. Gruit, is the name given to the flavouring. Sometimes a mix or blend was used often incorporating a blossom.
Blossoms can add additional yeast to the brew.
Before final straining of the brew any yeast that had grown would be removed and added to the next brew at the start of the next fermentation. Some extra yeast can be obtained from certain gruits. The purpose of yeast in the brew is to create alcohol. As some of you may have noticed this is a particularly popular ingredient in any beer. Mash is the name given to the mix of malt and gruit which are allowed to ferment together.