How do brewers measure the alcohol in beer?
To determine the amount of alcohol in the beer they are making, brewers compare the specific gravity of the beer before it starts fermenting to its specific gravity when it is finished fermenting. The specific gravity is a measure of the density of a liquid relative to water. The density of water is 1 kilogram per liter, so if the specific gravity of a liquid is 1.06, one liter of that liquid will weigh 1.06 kg. A hydrometer used to measure the specific gravity of liquids. Notice the reading of 1.000 for water. The liquid that will form the beer is called a wort (pronounced wert). Its specific gravity is always higher than water because it contains a lot of dissolved sugars. Yeast added to the wort will convert some of these dissolved sugars into ethyl alcohol. When the beer is finished, the specific gravity is always less than when it started, because some of the sugars have been converted into alcohol, which is less dense than water (0.79 kg/L). Quiz Corner Think you are an expert on
