specific gravity vs alcohol %

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napsternova
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specific gravity vs alcohol %

Post by napsternova »

I'm just wondering what the difference is between testing for alcohol content and specific gravity? Am I wrong in thinking that if my batch tests appropriate for alcohol content that it's ready to bottle?
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swenocha
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Re: specific gravity vs alcohol %

Post by swenocha »

Wellllll.... yes and no. If, based on your measured OG and FG readings, think you are at the abv you expected, you may well be done. But sometimes the yeasties like to party a little longer than the estimate. The best way, IMHO, is to take readings over a few days. If they are stable (i.e., you get the same reading each day), you're likely done.
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Re: specific gravity vs alcohol %

Post by HerbMeowing »

Testing for alcohol content won't tell you if fermentation is over.
A recipe's ABV is an estimate only.

As for sampling daily; such a waste.

If you must; then draw a sample.
Sample again three days later.
Stable? It's 'GO' for packaging!

More better - let it ride three weeks ... then package.
Better to go long than risk bottle bombs.
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swenocha
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Re: specific gravity vs alcohol %

Post by swenocha »

I suppose I should have been more clear, as I didn't really mean to take readings daily (yes, that would be a waste). I'm saying the exact same thing you are... If you take a couple readings spread over a few days, and you get the same reading each day, you are likely done.
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nada... zip...

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nada... zip... maybe an N/A beer here and there...
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Dawg LB Steve
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Re: specific gravity vs alcohol %

Post by Dawg LB Steve »

At the 2 week mark I pull my sample, check gravity then wad up a paper towel,foam plug or even a sanitzed piece of foil loosely covering the top to keep wild stuff out, the CO2 will push it out a bit if it is still fermenting but you are only using one sample tube. At the end I pour it off slowly ( so I don't get any of the layer of trub ) into a pint mason jar and put in the fridge to get a taste of what's to come once it is carbed up.
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Re: specific gravity vs alcohol %

Post by ScrewyBrewer »

napsternova wrote:I'm just wondering what the difference is between testing for alcohol content and specific gravity? Am I wrong in thinking that if my batch tests appropriate for alcohol content that it's ready to bottle?
Becoming more familiar with the attenuation rate of different yeast strains, or how completely they're expected to ferment wort sugars into alcohol and Co2 may be the answer to your question. Under the best conditions for example White Labs WLP810 - San Francisco Lager Yeast™ will only attenuate 65-70% of your original gravity reading. I use Screwy Calc to do the math for me but a quick method of calculating AA% is to divide your original gravity by 4.

OG = 1.050 (Shorten it to 50)
50 / 4 = 12.5 for a final gravity of 1.0125

But there's a catch, the apparent attenuation (AA%) to take 1.050 down to 1.025 works out to be 73%, which is higher than WLP810's 70% maximum range. Another thing to remember is that once the final gravity readings are stable for two days the yeast still needs several more days to cleanup the fermented beer, without changing the final gravity. I hope this helps.
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edwinm
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Post by edwinm »

how do i get more abv i just got a brewdemon 2 gal it came with the enhancer but id like the abv a lil higher but not high enuff to ruin the taste im thinking six any help would be awesome i have no exp
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Re: specific gravity vs alcohol %

Post by mashani »

The short answer is don't brew for ABV by trying to take some existing recipe and jack it up. That doesn't make better beer.

Instead, find recipes/styles of beer that are intended to be at a higher ABV to begin with and try those. That will be easier once you get beyond the HME and brew with extract and your own hops.

A slightly longer answer is that if you must, then more malt extract (assuming you are extract brewer) is normally better then sugar until you are brewing a style that sugar is more appropriate in.

In brew demon terms those would be the "pale horse", "red horse", "white horse", and "black horse" cans of extract. Just find the one that has similar attributes to the beer you are making (color, flavor) and throw in a can of it.

Those will make better beer then the "enhancer" most of the time.
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Re: specific gravity vs alcohol %

Post by John Sand »

Hi Edwin, welcome to the Borg!
Mashani is a very smart brewer, it is wise to listen to him. I agree that it is better to brew according to established recipes and kit instructions to gain experience. I was tempted to experiment by modifying kits when I first started too. The results were not very good. Then I studied brewing, and practiced. I still make mistakes, but I also make some really good beer. You will too.
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Re: specific gravity vs alcohol %

Post by Whamolagan »

Ok there is a little different trains of thought here. You can get a Specific gravity of the same reading 3 days in a row, and fermentation may be done converting sugars. That is a start, there are other things that are happening after conversion from sugars to alcohol and co2. Without going deep into all of the details, there are other compounds that need to be cleared out like sulfur and diactyls. If bottled too early, these can come through in the final taste. Most will settle out after time. One of the best ways is to taste test before bottling or kegging. I like to go by clarity and taste. Just my 2 cents that is worth beach front property in Arizona
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Re: specific gravity vs alcohol %

Post by bpgreen »

mashani wrote:The short answer is don't brew for ABV by trying to take some existing recipe and jack it up. That doesn't make better beer.

Instead, find recipes/styles of beer that are intended to be at a higher ABV to begin with and try those. That will be easier once you get beyond the HME and brew with extract and your own hops.

A slightly longer answer is that if you must, then more malt extract (assuming you are extract brewer) is normally better then sugar until you are brewing a style that sugar is more appropriate in.

In brew demon terms those would be the "pale horse", "red horse", "white horse", and "black horse" cans of extract. Just find the one that has similar attributes to the beer you are making (color, flavor) and throw in a can of it.

Those will make better beer then the "enhancer" most of the time.
+1

The worst beer I ever made was one agate I was chasing abv. It ended up around 9%, but s was almost undrinkable. I also brewed a beer that came in over 10% and was delicious. The difference is that the second beer was high abv because it fit the recipe and the first was because I was just going for high abv.
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Dawg LB Steve
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Re: specific gravity vs alcohol %

Post by Dawg LB Steve »

mashani wrote:The short answer is don't brew for ABV by trying to take some existing recipe and jack it up. That doesn't make better beer.

Instead, find recipes/styles of beer that are intended to be at a higher ABV to begin with and try those. That will be easier once you get beyond the HME and brew with extract and your own hops.

A slightly longer answer is that if you must, then more malt extract (assuming you are extract brewer) is normally better then sugar until you are brewing a style that sugar is more appropriate in.

In brew demon terms those would be the "pale horse", "red horse", "white horse", and "black horse" cans of extract. Just find the one that has similar attributes to the beer you are making (color, flavor) and throw in a can of it.

Those will make better beer then the "enhancer" most of the time.
^^^^^^^^^^^^^^^^ YEP THIS^^^^^^^^^^^^^^^^^^^
MONTUCKY BREWING
Currently brewing:

Next Up?
Kolsch?
Ginger Beer?
Traveling Red?
Yazoo Gerst Clone?
Peanut Butter Porter?

Currently Conditioning:
Cherry Mead
California Moscato

Currently enjoying:
Hardly Apple Cider on tap
Hardly Cherry Lime-Aid on tap
Oktoberfestive-Ale on tap
PGA Cider (Pear, Ginger, Apple) on tap 3rd Founders Cup 2016 King Of The Mountain on tap
Bottoms Up Brown on tap GOLD 2016 Ohio Brew Week Silver 2016 Ohio State Fair Silver 2016 Son of Brewzilla, Silver 2015 Son of Brewzilla, Bronze 2015 King Of The Mountain on tap
NITWIT BELGIAN STRONG ALE Banjo-Dawg RCE bottled
DAWG LB PALE ALE bottled
CITRA SLAPPED AMBER ALE bottle
MO FREEDOM SMaSH bottle
HOP TO IT IMPERIAL IPA bottle

Medal Count
Gold 3
Silver 5
Bronze 5
Actively brewing since December 2013
edwinm
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Re: specific gravity vs alcohol %

Post by edwinm »

thanks guys im using it according to the recipe ..lol
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John Sand
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Re: specific gravity vs alcohol %

Post by John Sand »

Good idea, Ed. Keep us posted. There are recipes and kits for thousands of beers, this is great ride.
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Re: specific gravity vs alcohol %

Post by bpgreen »

John Sand wrote:Good idea, Ed. Keep us posted. There are recipes and kits for thousands of beers, this is great ride.
And once you start making your own, there's no limit to the number of possibilities (just don't go hog wild adding ingredients right off the bat; learn what different things bring to the table first).
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