Chocolate Stout increasing ABV

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Chocolate Stout increasing ABV

Postby trabfountain » Tuesday Aug 13, 2013 9:22 am

My chocolate stout has been in the FV for 10 days. OG was 1.060 and it is now 1.016. According to my calculations that makes an ABV of 5.77%. I would like to increase this somewhat and wonder if the yeast would start working again with a gentle stir and if this would lower the FG reading.
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Re: Chocolate Stout increasing ABV

Postby weizgei » Tuesday Aug 13, 2013 9:31 am

If you want to be certain, try a forced ferment test. Take 200ml or so out of the fermenter into a sanitised container, like a coke bottle. Take it inside, and shake the bejebus out of it as often as you remember. Keep the lid tight while shaking, then loosen it up in between shakes to let out any co2. After 24 hours of this, take a gravity reading on this sample. If it's fermented below the 1016 you already measured, then there are still fermentables left in your wort, and a gentle stir/swirl of the fermenter, and perhaps bringing the temp up 2 or 3 degrees could see it drop further.

If (as I suspect) the wort is still at 1016, then the beer is done, and the only way to up the abv would be to add fermentables (such as you do when priming). Are you kegging or bottling this brew? Either way you could get a ~0.4% bump from priming. How high do you want the abv?
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Re: Chocolate Stout increasing ABV

Postby trabfountain » Tuesday Aug 13, 2013 9:39 am

Thanks weizgei for your suggestion. I would like to get this to around 6.3% and I am bottling this.
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Re: Chocolate Stout increasing ABV

Postby weizgei » Tuesday Aug 13, 2013 1:59 pm

Just to make sure we're clear, if you're at 5.77% now, and you bottle it with a priming rate of say 2.5 vols of co2, you'll be up around 6.2%. Close enough no?

Also, with an OG/FG of 1060/1016, that's actually 5.9%, not 5.77%. So with priming you'll be pretty much spot on 6.3% I think.
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Re: Chocolate Stout increasing ABV

Postby trabfountain » Tuesday Aug 13, 2013 4:00 pm

Thanks weizgei 6.2% is certainly close enough. I'm curious how you calculate 5.9% I've always used a formula I found on a brew site somewhere which is OG - FG x 131.25. Maybe I've been using the wrong method for calculating ABV. I'd certainly be interested in your method.
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Re: Chocolate Stout increasing ABV

Postby Guru » Tuesday Aug 13, 2013 5:30 pm

I have seen various methods for calculating Alc/Vol on the net and ended up just choosing one that suited me.
Currently this is what I use. The plus 0.5 is for the extra fermentation in the bottle. In my notes this I mention this as the Coopers method, whatever that may mean.

(OG x 1000 - FG x 1000) / 7.46 + 0.5
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Re: Chocolate Stout increasing ABV

Postby weizgei » Tuesday Aug 13, 2013 6:09 pm

I'm with guru, OG-FG divided by 7.46. Then I add 0.4% for priming (either in the bottle or keg).
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Re: Chocolate Stout increasing ABV

Postby enzo_damario » Saturday Mar 12, 2016 10:56 am

Guru wrote:I have seen various methods for calculating Alc/Vol on the net and ended up just choosing one that suited me.
Currently this is what I use. The plus 0.5 is for the extra fermentation in the bottle. In my notes this I mention this as the Coopers method, whatever that may mean.

(OG x 1000 - FG x 1000) / 7.46 + 0.5


1000 / 7.46 = 134.048... instead of 131.25... hence the little difference...
trabfountain wrote:Thanks weizgei 6.2% is certainly close enough. I'm curious how you calculate 5.9% I've always used a formula I found on a brew site somewhere which is OG - FG x 131.25. Maybe I've been using the wrong method for calculating ABV. I'd certainly be interested in your method.
Cheers
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