Some of these factors include temperature and moisture content of the ingredients. Even the slightest change in any one of them can alter the density of a sample of beer. There are many different types of beer, each with a slightly different density. Some of these types are ale, lager, and wheat. Each is made differently but all contain the same basic ingredients.
Specific gravity is the density of a substance divided by the density of water.
Therefore, the density is mostly a measure of the amount of water contained within a beer. A beer with a higher percentage of water will have a correspondingly lower density. These changes are not necessarily connected directly to the amount of water added. Changes in moisture content of malts can also alter density. Because of this, each component of beer needs to be closely scrutinized before it is added into the mix.