Author Topic: Understanding OG calculation  (Read 3041 times)

Offline ballkn

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Understanding OG calculation
« on: June 13, 2015, 09:30:34 PM »
All, Newb here. I apologize in advance for my ignorance. I am trying to understand why my back of the envelope calculations for OG do not equal what the software yields. Can someone help me understand how the software is calculating an OG of 1.060. I calculate ~ 1.080


Offline brewfun

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Re: Understanding OG calculation
« Reply #1 on: June 14, 2015, 07:44:08 AM »
With extract recipes, BeerSmith assumes only 15% efficiency for steeped grain. If you know you get more than that, you can change the percentage in Options.
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Offline ballkn

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Re: Understanding OG calculation
« Reply #2 on: June 14, 2015, 07:57:38 AM »
I thought this might be the case, but am still not quite calculating their predicted 1.060. I am multiplying the extract SG of 1.036 by the total amount of extract (9lbs). This value is then divided by my batch size of 5gallons. This yields ~65. I assume the calculator applies some efficiency to the extract as well... Maybe 85%?

Offline brewfun

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Re: Understanding OG calculation
« Reply #3 on: June 14, 2015, 08:02:11 AM »
No, extract is utilized at 100% because all of it dissolves into wort. That's what BeerSmith assumes. The ingredient profile should show 100% yield. If it doesn't, change it to see if that makes the difference.

Beer Appreciation is the space between pints.

Offline Oginme

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Re: Understanding OG calculation
« Reply #4 on: June 14, 2015, 09:16:53 AM »
Without seeing your water balance, it is hard to check the calculation.   It appears as though you are doing a partial boil and topping off into the fermentor.   BrewFun is correct that extract is calculated at 100% yield, but how much of that is lost in your trub loss?
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