ABV Question

[brew703]

What causes higher ABV and what causes lower ABV.

I'm just curious as I brewed a Zombie Dust clone and a Rye PA.
The ZD came in 10 points higher on Post boil OG. FG was 1.017, which is two points higher than the recipe stated. The ABV should have been 6.31%. BF shows 7.88%.

The Rye PA hit all marks. The ABV should have been 6.6%, however BF shows 5.64%. The BF numbers are after taking FG readings.


I figured the ZD would be a bit higher due to the higher OG.

Just trying to figure out why the difference.

 

[Moose_MI]

It's not really where you start (OG)....and it's not really where you finish (FG).....it's the distance that you travel.... OG-FG .... And a bunch of math that online ABV calculators do for you

 

[brew703]

Ok so how can I make sure I hit the ABV mark? Just trying to figure out if it's my process or some other factor I need to correct.

 

[Moose_MI]

To hit ABV you have to hit OG and FG. Not sure there is 1 right answer but for OG I guess you measure at end of boil...if it's high you can dilute with a little water....if it's low you can add some DME. As far as Fg goes it's mostly about getting the anticipated attenuation for your yeast so pitch the right amount of healthy yeast into aerated wort and keep the temp in happy range


.....oh, and probably 50 other things.

 

[Yooper]

Ok so how can I make sure I hit the ABV mark? Just trying to figure out if it's my process or some other factor I need to correct.

Hitting the OG is part of it for sure- generally higher OG beers have more fermentables, so the ABV will be higher.

The other part is the FG. Where the beer finishes. Some beers, say like an oatmeal stout, will have less fermentables in them and so have more body and dextrin and unfermentables. My oatmeal stout finishes at about 1.018.

My IPA is crisp and dry, and I mash at a low temperature to get a lighter body. That beer finishes at 1.010.

So, say both beers start at 1.060.

The formula for estimating the ABV is (FG-OG) x 131.

So, for the stout:

(1.060- 1.018) x 131 = 5.5%

For the IPA:
(1.060- 1.010) x 131 = 6.55%

So, it's a combination of where it starts and where it finishes. Several things also impact where it finishes- mash temp, yeast strain, ingredients, etc. So you can manipulate all of those things to create the balance of the beer you want.

 

[jcav]

Hitting the OG is part of it for sure- generally higher OG beers have more fermentables, so the ABV will be higher.

The other part is the FG. Where the beer finishes. Some beers, say like an oatmeal stout, will have less fermentables in them and so have more body and dextrin and unfermentables. My oatmeal stout finishes at about 1.018.

My IPA is crisp and dry, and I mash at a low temperature to get a lighter body. That beer finishes at 1.010.

So, say both beers start at 1.060.

The formula for estimating the ABV is (FG-OG) x 131.

So, for the stout:

(1.060- 1.018) x 131 = 5.5%

For the IPA:
(1.060- 1.010) x 131 = 6.55%

So, it's a combination of where it starts and where it finishes. Several things also impact where it finishes- mash temp, yeast strain, ingredients, etc. So you can manipulate all of those things to create the balance of the beer you want.

This is the most concise and accurate way I have ever heard it clearly explained, without going on and on and on. Great post Yooper!

John

 

[beergolf]

The formula for estimating the ABV is (FG-OG) x 131.

Ooops you got it backwards. Coffee must not have kicked in yet. Did the math part right, though.

Formula is (OG-FG) x 131

 

[brew703]

Hitting the OG is part of it for sure- generally higher OG beers have more fermentables, so the ABV will be higher.

The other part is the FG. Where the beer finishes. Some beers, say like an oatmeal stout, will have less fermentables in them and so have more body and dextrin and unfermentables. My oatmeal stout finishes at about 1.018.

My IPA is crisp and dry, and I mash at a low temperature to get a lighter body. That beer finishes at 1.010.

So, say both beers start at 1.060.

The formula for estimating the ABV is (FG-OG) x 131.

So, for the stout:

(1.060- 1.018) x 131 = 5.5%

For the IPA:
(1.060- 1.010) x 131 = 6.55%

So, it's a combination of where it starts and where it finishes. Several things also impact where it finishes- mash temp, yeast strain, ingredients, etc. So you can manipulate all of those things to create the balance of the beer you want.

That all makes sense Yooper. Thanks.
I figured the ZD would be higher since I missed my OG.I should have diluted with water but decided to let it ride.

For the Rye PA both OG and FG were within 1 point so I figured the ABV would be close. The mash temp was 152 for both.

Oh well, it is what it is.

 

[jcav]

I let BeerSmith tell me what my ABV is on my brews, as I have never figured it manually yet. Still an awesome post though......

 

[mongoose33]

I've been trying to duplicate the old version of Potosi Cave Ale, which showed an ABV of 6.5%.

I started with an English Mild Bitter extract recipe from my LHBS whose predicted OG and FG was:

OG = 1.045 - 1.049
FG = 1.009 - 1.014

That suggests a range of ABV from 4.061 to 5.24, with a mid-range of 4.65.

To meet something close to the 6.5 % figure from the old Cave Ale recipe, my LHBS owner suggested adding 2 more pounds of light DME, which I did.

I produced an OG of 1.063 with this recipe, and a FG of 1.016. That's a final ABV of 6.157.

So--I'm guessing that each pound of light DME added...about .75 ABV percentage points.

Take all this with a grain of salt--I'm a new brewer. But I will note that it's not terribly far away from what the old recipe produced. Going to drink some tonite watching the SB.

********************************************************

Potosi Brewing had a malt beer that is the best I've ever tasted. I was in love. Then they decided to produce their own brew in Potosi, hired a brewmaster who apparently thought screwing around with perfection was a good idea, and a lousy new recipe was born--this one with 5.5% ABV as opposed to the original 6.5%.

Who in their right mind screws around with a hit, which Cave Ale most assuredly was? When a beer penetrates the draught beer market in Madison, that tells you something. Unless you're a new brewmaster looking to make his mark.

When I called to complain I spoke w/ a marketing whizbang, who assured me the recipe hadn't changed. I noted it must have since ABV had declined by a percent. She said the old version wasn't correct--which is admitting that they knew the old labeling wasn't correct but ran with it anyway. Yeah, sure.

Turns out, I learned from other sources they changed the yeast. I guess that would account for the taste change, wouldn't it?

 

[Yooper]

Ooops you got it backwards. Coffee must not have kicked in yet. Did the math part right, though.

Formula is (OG-FG) x 131

Yep- you're right. first cup of coffee here! Thanks for fixing it for me.