I have noticed on a number of labels brewers include the OG of their beer, such as this: What should that value be telling me? I found this generic answer through a google search: Low OG, low FG: Usually a dry, light-bodied beer. Think a lot of your crisp lagers, wheat beers, etc. High OG, low FG: Usually a dry, full-bodied beer – probably also incredibly alcoholic. Think Abbey ales. High OG, high FG: Usually a sweeter, full-bodied beer. Low OG, high FG: Usually undrinkable. However, only having OG, we only know half of the puzzle. Also, what's considered "high" and "low"?
High gravity is typically anything brewed at or above 20 Plato; low gravity is around 14 Plato or below, there's no real official cut off for either. A lot of countries and some states base their excise taxes on the OG of a beer. If you know the ABV and OG, you can figure out roughly what the FG is, but the TTB doesn't require brewers to post either OG or FG on the label.
You can actually determine the FG by using the ABV and the OG. Since the FG is based on how much of the sugar originally in solution has been converted to alcohol by the yeast, knowing the percentage of alcohol lets you approximate the amount of sugar still left in solution in the finished beer.
Short answer: Original Gravity of the beer. This is a measurement of the dissolved sugar in the liquid. There are two basic formats: Plato and Specific Gravity (SG). After fermentation, the yeast eat the sugar and the gravity drops to the Final Gravity (FG). There are ways of calculating the alcohol percentage (ABV) by taking the difference between the OG and FG. You're right. Just having half the story (ie: just the OG and not the FG), it doesn't tell you much. However, one could make an educated guess of what the FG is based on the OG and ABV. High and low are obviously relative to style, but generally any SG over 1.080 is probably considered "higher." Jeff EDIT: Quick cal and the FG was probably around 1.005, or 1.5P.
Thanks for the replies, also learning about the Bitterness Ratio that you could calculate since you know the IBUs and OG http://beersmith.com/blog/2009/09/26/balancing-your-beer-with-the-bitterness-ratio/ All in all, i think its awesome for breweries to provide it, however its not something you can take a quick glance at and know too much from it without doing a little math
A litre of pure water weighs 1000 grams. During the brewing (mashing) process sugars dissolve which makes the liquid heavier.So the result (the wort) may weigh 1045 grams per litre. This is given as an OG of 1.045. For many normal beers the OG and ABV are very similar so a beer with OG of 1.045 ends up as 4.5% ABV. If the ABV is higher the beer tends to be drier , if lower the result is a sweeter beer.
The OG ton the label that the OP displayed shows the reading on the degrees Plato scale. I think the Specific Gravity scale is more commonly used, probably 100% by homebrewers, but I don't know how widespread the use of Plato might be by commercial brewers vs. the Specific Gravity. On the specific gravity scale, I think a 'big beer' will come in with its OG at a reading of 1.080 and above.
Homebrewers use Specific Gravity. Pros use Plato. A converter: http://www.brewersfriend.com/plato-to-sg-conversion-chart/
