Barm is the term used to describe the yeasty foam that appears on the surface of malt liquors during the fermentation process. This scum or frothy residue formed on the top of alcoholic beverages like beer or wine can be used as an efficient leavening agent in bread making as it is an excellent source of yeast organisms. In fact, English baking grants barm the status of a ‘natural leaven’. At times it may be used as a starter to initiate the fermentation process in a fresh stock of liquor as well. As such, a barm is best described as an intermediary step between harvesting the naturally occurring yeasts predominant in air and a proper sourdough starter. Thus making a barm is considered to be the second step in making sourdough bread. To create a barm one needs to begin with a seed culture which is the first step. The barm is also called a ‘mother starter’. This maybe due to the fact that various cultures can be isolated from barm for eg Saccharomyces cerevisiae, from which most forms of baker’s yeast and brewer’s yeast trace their origins.
Barm is prepared with unbleached high-gluten or bread flour, water at room temperature and a seed culture. This seed culture is considered to be the first step in sourdough bread-making. The flour, water and seed culture are blended together to produce a wet, sticky mass. Here one must be careful to incorporate the seed culture uniformly throughout the dough. It is also necessary to ensure consistent hydration all through. The barm is then slowly transferred; constantly dipping the spatula used in water to avoid sticking and wastage, into a container twice the size of the barm. The container is covered and set aside to allow fermentation over the next nearly 6 hours. By the end of this duration, the barm would have gradually risen pushing the lid placed on the container. The lid or cover is removed to allow the gas produced to escape. Once it settles, the lid is replaced and the barm is refrigerated overnight. Only then is the barm ready to be used the following day and it continues to be potent for the next three days.
Barm can also be manufactured using ground millet in combination with the musty remains obtained from wine-tubs.
In North-West England as well as in certain parts of Italy, a bread roll is prepared which turns out quite soft and fluffy, this is also commonly referred to as a barm or barm cake. However this is only a regional usage of the term. As a matter of fact, in Ireland, a fruited bread variant known as ‘’barmbrack” is manufactured using barm employing a traditional baking process.
The term ‘barmy’ is used as a slang to describe an individual’s high levels of frothy (effervescent) excitement.
