A measurement of the density of fermentable sugars in a mixture of malt and water with which a brewer begins a given batch. Found on http://www.beeradvocate.com/beer/101/terms/
Original gravity or OG is the specific gravity reading of a beers wort prior to having yeast pitched for fermentation. The original gravity reading is important because it gives the brewer an idea of how much sugar is available for fermentation and what the approximate alcohol by volume will be once fermentation completes. The original gravity read... Found on http://www.westcoastbrewer.com/Beer_Glossary_and_Brewing_Terms.php
Abbreviated O.G. Strictly speaking, the specific gravity, but usually taken Gravity to mean the degree Balling or Plato of the wort leaving the brew kettle. Found on http://www.winning-homebrew.com/brewing-terms.html
A measurement of the density of fermentable sugars in a mixture of malt and water with which a brewer begins a given batch Found on https://www.encyclo.co.uk/local/22617
A measure of the amount of sugars present prior to fermentation. In most homebrew recipes and texts, original gravity is measured using the specific gravity scale, though the Plato or potential alcohol scales may also be used on occasion. Found on https://www.encyclo.co.uk/local/22622