Alcohol Content in Brew

I have a question on the alcohol content in a particular recipe of homebrew. Can you raise or lower alcohol content of a recipe with technique or timing? What really affects the alcohol content in a recipe? I realize that a byproduct of fermentation is alcohol but how would you predetermine an alcohol content of a recipe?

Here's how I understand it so far:

You can forecast the alcohol content by using the specific gravity reading, which is simply the measure of sugar in the wort. Using a hydrometer, you take readings once the wort is cooled. This is the Starting Gravity, or Original Gravity. There are also methods to forecast the potential sugar production of a given grain bill or extract quantity, Check out How to Brew at http://www.howtobrew.com/section1/chapter1.html) When fermentation is done, you can take another reading, for the finished gravity. Using some math (which escapes me since I have an excel doc at home that does it for me) you can compute the Alcohol by weight and volume, in approximation. The way to controler alcohol content is by the amount of Malt or fermentable sugar you add to your brew. With All grain methods, technique and experience play a big role in sugar extraction efficiency, and therefore, potential alcohol production. In extract brewing, not so much, since the malt extract is basically the product of a grain mashing.

rcbrew said:

I have a question on the alcohol content in a particular recipe of homebrew. Can you raise or lower alcohol content of a recipe with technique or timing? What really affects the alcohol content in a recipe? I realize that a byproduct of fermentation is alcohol but how would you predetermine an alcohol content of a recipe?

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There are many software programs out there that you can use that will help you predetermine what your OG will be before you brew. Then depending on the yeast you use, the attenuation will be different. For instance, I am going to brew a beer that has a anticipated OG of 1.050. I am using a yeast with 80% attenuation. 80% of .050 is .040. My anticipated FG will be 1.010. Many here use a program called Promash. I have been using the recipator at http://hbd.org/recipator/.

I just got finished with an extract kit from Morebeer and on the note page that they provide it states that to calculate the Alcohol Content by Volume you take OG - FG * 131. Even I can remember this formula.

Thanks for the info........now taking this a step further.........can you take an existing recipe and reduce the alcohol content and still come up with a decent tasting brew? I have a family member that is on medication that cannot handle alcohol but still enjoys the taste of a good brew?

rcbrew said:

Thanks for the info........now taking this a step further.........can you take an existing recipe and reduce the alcohol content and still come up with a decent tasting brew? I have a family member that is on medication that cannot handle alcohol but still enjoys the taste of a good brew?

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You can make non-alcholic beer at home (and by "non-alcoholic", I mean that it will contain less that 0.5% abv, just like most commercial non-alcoholic beers contain).

What you need to to is ferment the whole thing as normal. When it is done, you put it back into a kettle and heat it up to boiling. All of the alcohol will evaporate by doing this and you are left with 0% ABV beer.

Then, you make up your priming sugar solution and and put that (along with some fresh yeast) into the cooled non-alcoholic beer, stir it up, and bottle it.

The yeast will eat the priming sugar and carbonate the beer, and this should produce less than 0.5% ABV in the final product.

-walker

What would boiling the beer again possibly do to the taste?

you don't actually need to boil it. just bring it up to the point of boiling. Alcohol boils at something like 180 degrees (I think) so as soon as the beer starts heating up over 180 degrees (or whatever it is) the alcohol will be long gone.

-walker

Walker said:

you don't actually need to boil it. just bring it up to the point of boiling. Alcohol boils at something like 180 degrees (I think) so as soon as the beer starts heating up over 180 degrees (or whatever it is) the alcohol will be long gone.

-walker

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And then you collect the part that evaporates and run it through a radiator and copper tubing.

and you end up with about 20 oz of rocket fuel.

.. um... wait.. I think that's illegal.

-walker

So what size copper tubing is that?

Right! If you monitor the temperature, it will stop rising around 172F until most of the alcohol is gone. When it starts rising again cool immediately.

Thanks for the info.......so.....I can do a partial batch of NA and bottle the rest in a "normally", right?
P.S. This web site is great, I am learning soooooo much...

So what size copper tubing is that?

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3/8ths of a inch into a slobber box, then a thumper, then into your counter flow wort chiller works fine. . . from what I have read

I'm still looking for a cheep pressure cooker

rcbrew said:

Thanks for the info.......so.....I can do a partial batch of NA and bottle the rest in a "normally", right?
P.S. This web site is great, I am learning soooooo much...

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Yes, you can do this. Just make sure you cut the amount of priming sugar in half since you are bottling two separate half-batches.

-walker