OG/FG and its bearing on primary fermentation - Home Brew Forums

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Old 11-11-2009, 10:09 PM   #1
gtpro
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This is my first brew ever, its 6.6 lbs of amber LME. I must have gotten too excited and forgot to check the OG, I've thought about it a couple times since, but I don't want to risk infection, plus from what I had gathered at the time all it tells you is the abv% of your beer, which I don't particularly care about.

It has since occurred to me that a stable FG will tell me that fermentation is complete, but since I dont have an OG to compare it to, am I able to extract any meaningful information from my FG reading? What kind of reading would be reasonable to expect with 6.6 lbs of LME? And should I use these reading to tell me when to rack, or just stick it out for 2-4 weeks in primary to condition?

 
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Old 11-11-2009, 10:26 PM   #2
mavandeh
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If you use a well sterilized thief, infection is not something you need worry about. It never hurts to be mindful of resterilizing your bung/airlock before replacing it either. A your yeast will also create a competitive environment for any other organism that may infect your brew. People have brewed beer for a long long time; way before Pasteur, van Leewenhoek, or Koch were born. RDWHAHB!

Your OG will depend on a lot of things. Being a newbie myself, I don't know it all. However, I can venture an educated guess that the solute content of your extract, your specialty grains, hops, and the amount of water you use to bring your batch to its final volume will all factor into this. How long has it been in there? Can't hurt to take a reading now and track the change!

In my brown ale, I used a dark and an amber extract. The OG was somewhere around 1.062, but I was using an unconventional style of hydrometer -- long story.

Being somewhat impatient also, I am going to keep testing the gravity of my brown for a while before I bottle it. I'll shoot for 4 weeks, but the longer you leave it in the fermenter, the longer you give the yeast time to clean up the off-flavors created by the fermentation process. Let it sit on the yeast cake for a while and try to keep your mind on other things!

Hope this helps!


 
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Old 11-11-2009, 10:26 PM   #3
Scimmia
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LME will give you 36 points per pound per gallon. 36 x 6.6 lb = 238 points. Assuming you ended up with 5 gallon in the fermenter, that's 238/5 = 48 (rounded), so your OG should have been around 1.048, assuming no other fermentables.


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Old 11-11-2009, 10:32 PM   #4
mavandeh
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Was it 6.6 pounds of light malt extract (LME) or amber malt extract (AME)?

 
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Old 11-11-2009, 10:35 PM   #5
Scimmia
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LME means Liquid Malt Extract, not light. He specified it was amber.

 
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Old 11-11-2009, 10:38 PM   #6
mavandeh
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Okay, my bad there! DME = dry then.

I've been told. :P

 
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Old 11-11-2009, 10:57 PM   #7
ajf
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Quote:
Originally Posted by mavandeh View Post
Okay, my bad there! DME = dry then.

I've been told. :P
Yes, unless you live in UK, when DME can mean Diastatic Malt Extract (which is a liquid).

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