Stuff from BYO Eff Q's

[hopsalot]

brew efficiency overview

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SMaTH Brewed 12-17-08 kegged 1-19-08

12# vienna
1 oz Centennial (8.00% AA 60 min)
2 oz Cascade (5-6?% AA 1 oz 30 min, 1 oz 5 min )

Mash 154*F, 4.5 gal, 1 hour
Sparge 180*F, 4 gal

Boil volume: 7-7.5 gal
Boil 1 hour
End volume: 5.5 gal

SG: 1.034
OG: 1.060
FG: 1.014

I calculate ABV: 6.03%

So here are my thoughts/questions. The beer is great very clear, yeasty and citrusy. Has turned out to be a great people pleaser. All grain is as easy as you want it to be but I am interested in the actual efficiency of my system in order to get better data for online brew calculators.

12# Vienna
F. gravity 1.060

GU = (Grav-1)x1000
GU = 60 GU

GU of total gravity = 60 GU*5.5 gal = 330 total GU
12 # Vienna = 330 GU

total grav of wort = (SG-1)*1000 * boil volume
= 34 GU * 7 Gal (pre boil) = 238

Eff = total gravity of wort/total potential gravity of grains
Eff = 238/330 = 72%

I know this may be over kill but for all who are interested does the math check out? I think that my SG is wrong but I am just interestd in the math, might write a program this weekend to do it for me, need to refresh my C++

 

[notwoohoo]

What was your gravity in the fermenter? If it was 1.060, my calculations for 12lbs of Vienna yield ~95% if your volume was 5.5 gallons. That is too high. I'd make sure to check your volume determinations as being off by a pint will skew your efficiency by about 5%. The key to a reliable efficiency calculation is a valid volume measurement. I purchased a 500mL+-5mL graduated cylinder from a lab supply shop in order to calibrate my system. Hope this helps!

 

[hopsalot]

yah I need to be more aware of my volumes, I need to graduate my spoon. Yah I was bored and felt like doing some of the problems in Designing Great Beers, not really sure why I titled the thread "BYO". Did not know that efficiency could be affected that much by volume, next brew I am going to try to calculate my actual efficiency, thanks

 

[sause]

I ran it through a brewing program and it came out at 74%. So your math is darn close to correct.