What is original gravity in beer?

Answered by John Watkins

Original gravity (OG) is a crucial term in the world of as it provides brewers with valuable information about the potential content of their . It measures the amount of dissolved sugars present in the wort before fermentation. These sugars primarily come from malted grains, such as barley, which undergo a mashing process to extract their sugars.

As a brewer, I have come to appreciate the significance of OG in the brewing process. It serves as a starting point, a foundation upon which the entire brewing journey is built. When the malted grains are mixed with hot during mashing, enzymes present in the grains convert starches into fermentable sugars. The resulting sweet liquid, known as wort, contains a variety of sugars that can be consumed by during fermentation.

To determine the OG, brewers use a hydrometer, a tool that measures the density of the wort. This measurement is typically taken before the yeast is added. The hydrometer floats in the wort, and by observing the level at which it floats, brewers can determine the density of the liquid. This density is then compared to the density of water, and the difference is expressed as the OG. The OG is usually expressed as a specific gravity (SG) reading, which is a dimensionless number.

The OG reading is directly related to the amount of fermentable sugars in the wort. The higher the OG, the more sugars are present, and thus the more potential there is for the yeast to convert these sugars into alcohol. This means that a beer with a higher OG will generally have a higher alcohol content compared to a beer with a lower OG.

In my experience as a brewer, I have found that the OG reading is not only an indication of potential alcohol percentage but also provides insights into the beer's body and sweetness. Beers with a higher OG tend to have a fuller body and a sweeter taste, as the remaining unfermented sugars contribute to the overall flavor profile.

It is important to note that the OG reading is just the starting point of fermentation. As the yeast consumes the sugars in the wort, it produces alcohol and carbon dioxide. The fermentation process converts the wort into beer, and the final alcohol content will depend on various factors, including the yeast strain used, fermentation temperature, and the overall health of the yeast.

Original gravity (OG) is a measurement that indicates the amount of dissolved sugars in the wort before fermentation. It serves as a guide for brewers, providing them with information about the potential alcohol content of their beer. A higher OG means more sugars are present, leading to a higher potential alcohol percentage. However, the final alcohol content will depend on the fermentation process. Understanding and monitoring the OG allows brewers to have control over the flavor, body, and alcohol content of their beer.