This article was previously posted on the Examiner as part of my Science of Beer series.
This is part one of what will become a multi-article study into the science behind making beer.
Apart from water, barley is the main ingredient in beer. The barley is what determines the color and primary taste as well as dictates how much alcohol will be present within the beer in the end.
To create malt, barley grains combine with just enough water that they begin to germinate as though they are being planted into the ground. When barley begins to germinate, it releases an enzyme called amylase. The purpose of amylase is to break down the starches within the barley into smaller carbohydrates that can be used as an energy source for the sprouting plantlet. Human saliva also contains amylase to begin breaking down the food we eat before entering the stomach. Without amylase to break down the carbohydrates, sugars cannot be extracted from the barley to later be converted into alcohol.
In order to stop the germination process, heat is applied to the barley to completely dry it out. This process can be done in a number of different ways and is what differentiates one type of malt from another. Either the heat can be slowly and gradually added to the malt, leaving the color pale with no noticeable roasted characteristics, or it can be left heated long enough that the barley darkens and turns various shades of brown or even becomes blackened. Another common method is to add a very high heat very quickly to caramelize the outer edge into a reddish color. Depending on the combination of malts used in a brewing recipe, the flavor and color of the beer can be determined.
Breweries typically purchase barley already malted and will then begin the first step of creating beer, mashing. Mashing involves milling the grain and letting it soak in hot water, typically around 150 degrees Fahrenheit, for about an hour. The ultimate goal in mashing is to release the sugars from the malt into the water creating a sweet liquid called wort. Wort is simply unfermented beer. Later when yeast is added to the wort, sugars are converted in alcohol and thus wort becomes beer.
The amount of malt used in a beer will vary from one recipe to the next. Since the purpose of malt is to release sugars that later get converted into alcohol, you would typically add more malt if you want more sugars, and in turn, more alcohol. For 5% alcohol by volume beer, you would use about one pound of malt for four pints. If this beer were to be one 15 gallon keg of beer, about 30 pounds of barley would need to be mashed.
Once the malt is mashed, the wort is drained from the grains and moved on to be boiled and have the hops added. This will be discussed further in a future article on hops.