by Matt DeMarco
One amazing thing about beer is that despite the multitude
of brands and styles there are only 2 classifications of beer--lagers and ales.
For example, a pilsner is part of the
lager family and IPAs are part of the ale family. These classifications are
based on the type of yeast used in fermentation. Prior to fermentation, malt is
cracked to release the starch within the grain and then mixed with water. The mixture or wort is then heated to convert
the starch into sugars. Fermentation
begins when yeast is added to the wort. During
fermentation, the yeast feeds on the sugar excreting alcohol and C02. Top fermenting or ale yeast stays on top of
the wort while it is active and then sinks to the bottom when all of the
fermentable sugar is consumed. Bottom fermenting yeast or lager yeast is the
opposite and stays on the bottom of the wort the whole time.
