I do not understand OG and FG readings

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I do not understand OG and FG readings

Postby crueli07 » Wed May 31, 2006 11:13 am

What do these mean ( I literally know what they mean)? What do they mean for my beer? What should I be looking for? I need the explanation in simple terms if possible. Thank you.
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Postby BillyBock » Wed May 31, 2006 5:22 pm

OG means 'Original Gravity' and is the specific gravity measurement of your wort before you add yeast.

FG means 'Final Gravity' and is the specific gravity measurement of your finished beer after the yeast has completed their job.

Both measurements are typically taken with a hydrometer which measures fluid density relative to a reference. The reference reading is for water, which has a specific gravity of 1.000. Readings greater than 1.000 are more dense than water, and readings less than 1.000 are less dense. As examples, if you see a beer with an OG of 48...the real hydrometer reading is 1.048. If you see an FG reading of 10...the hydrometer reading would be 1.010. Yeast don't fully metabolize wort constiuents, so they will leave unfermented components in the wort. It's these items that define the FG of the beer and help give it body and sweetness. The higher the FG the more 'sweet' a beer is. The closer an FG is to water, the 'drier' the beer is said to be...meaning it doesn't have a lot of residual sweetness.

These values are used to determine the alcohol strength of your beer. Your typical strength beer has an OG of 1.048. An IPA may have an OG of 1.070 and a Barleywine could be 1.110.

Hopefully this helps some. Let me know if you have more questions.
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