Does the O.G serve as any indication of the ABV%?

[Zachandlutz]

I'm new the home brewing. I actually just order my brewing kit a few days ago. I have brewed one batch before with some buddies but we didn't take it too seriously and in some part of the process, we screwed it up.

As I was looking at some of the recipe kits on Northern Brewer, it tells you the O.G. My question is if a recipe I am interested in has an O.G at 1053, is there a way to get a general sense of what the ABV% will be after fermentation?

 

[GuldTuborg]

Yes. Assuming normal brewing processes, you can get a rough gauge of your eventual ABV by looking at the recipe and OG. Gravity is just a measure of the density of a liquid, but if you did your job right, most of that density should come in the form of fermentable sugar.

For a stupid rough guide, I'd say you can estimate anything in the 1.030s to be roughly 3%, 1.040s to be 4%, etc., when all is said and done. Of course, if you use a lot of ingredients with high or low fermentability, that'll change things drastically. If you end up treating your yeast particularly well or poorly, that'll change things. If you select one of the few super performer or super floccing yeasts, or add brett or bugs to the equation, that'll change things. But for most recipes, this is a good starting point.

If you want to get an accurate number, though, run your OG and FG (along with temps) through a calculator online. You'll get a fairly accurate idea of what your ABV really is.

 

[BlueHouseBrewhaus]

Subtract your FG from your OG and multiply by 131.25.

Example:
OG 1.065
FG 1.015

1.065 - 1.015 = 0.050
0.050 X 131.25 = 6.56% ABV

As you can see, there are two ways ABV can be increased. You can brew higher gravity (i.e. raise OG) and/or you can increase fermentability (i.e. lower FG) by mashing lower, adding high fermentables (e.g. corn sugar), or limiting low fermentabilty grains and adjuncts.

 

[Calder]

As a very general rule:

1.050 = 5.0% abv
1.055 = 5.5% abv
1.070 = 7.0% abv

I think you get it.

But ....... it also depends on the style of beer and FG:

- If it is a Belgian style of beer, where a dry finish is desired, and there are a lot of fermentable sugars, you will get higher alcohol levels.
- If it is a sweet stout or other 'sweetish' beer. the alcohol level will be lower due to a higher amount of unfermentable sugars in the mix.

(OG-FG)*131=abv

For a 75% attenuation beer (standard expectation); a 1.060 OG down to 1.015 would be:

(1.060-1.015)*131=5.9%

 

[Zachandlutz]

Thanks everyone. I'll probably be posting on brew day and during the rest of the process.

Cheers!

 

[urg8rb8]

OG can kinda give you an estimate. However, there are many factors that can influence the ABV of the finished product: mash temps, malts/sugars used, etc...

 

[Qhrumphf]

As said, there's a lot of factors that go into it, but all else being equal the higher the OG the higher the ABV. Emphasis on all else being equal. Highly possible to have a Saison with a highly attenuative yeast start at a lower OG but have a higher ABV than a beer brewed with a lower attenuative English yeast with a higher OG.

See what @Calder said, that's probably a good general "guide" although by no means all-inclusive.