Help estimating Alcohol %

rjm · 04-21-2006, 03:45 PM

In the vein of Kevin K’s recent post, I wonder if someone could help me out with some calculations.

I didn’t get a good reading of my OG, but here is the extract + steeped grain recipe I followed:

2 kg (4.4 pounds) Extra light DME
1.5 pounds of Medium Crystal steeped slowly until the temperature reached just shy of 200F (I now know this is a bit high, but that is what my recipe called for)
And hops at the various stages…

I do not plan to rack to a secondary (I know, I know – again recipe said it wasn’t necessary for this beer, and my first), and it has been in the primary for 10 days. I took a reading of the gravity today (day 10):

1.014 at 61F, hydrometer says that it is calibrated to 68F
-0.001 recommended adjustment for 59F, the closest on the list
= 0.013

The recipe says that the gravity should be 1.050, and with a 5.5 to 5.8% alcohol/vol. What does the 1.050 mean? Is that the target final gravity? According to the little chart that came with my hydrometer, my 0.013 reading means that it has a potential alcohol content of 1.48% but because I don’t know the OG I cant do the subtraction to find out the estimated alcohol content. Can anyone help me here with an estimate?

I will take another reading on Sunday and then again on Monday to see if it is staying constant at 0.013 and then I will bottle Tuesday or Wednesday. Does this seem right? Should it drop to 1.050?

P.S. I am relaxed, and will have a store bought brew with lunch, but I’m just learning this stuff and I’m excited to figure it out. I appreciate everyone’s advice so far. This is a great board, and I’m glad I found it.

**Walker** · 04-21-2006, 04:02 PM

1.050 is the estimated STARTING GRAVITY for the recipe.
You have a measured FINISHING GRAVITY of 1.013.

This gives an approximate abv of 4.8%.

One more thing... the way you use the "abv" scale on the hydrometer is to take a reading before fermentation, and take a reading after fermentaton and subtract the final reading from the original reading. This gives you the abv in a straight percentage value.

One final thing... I don't believe the recipe when it states that the estimated startikng gravity is 1.050 and the estimated abv is appx 5.7%. You would need to have a finishing gravity of 1.006 (dropped from the original 1.050) to hit that abv target, and 1.006 is a VERY low gravity and would be a very thin beer.

-walker

Desert_Sky · 04-21-2006, 04:05 PM

1.050 was your OG you should of gotten when you pitched your yeast

And assuming you were close

1.050 - 1.013 = .037

then

.037 * 131 = 4.8% ABV

*edit

Walker beat me to it

**budbo** · 04-21-2006, 04:18 PM

I have given up on using a hydrometer, They do nothing for me but cause stress and make me want to kick my dog (a homebrew makes that feeling pass)

**Walker** · 04-21-2006, 04:27 PM

hmmm.. that reminds me of someone's signature.

oh yeah! it reminds me of MY signature.

**Baron von BeeGee** · 04-21-2006, 05:12 PM

I love hydrometers.

rjm · 04-21-2006, 06:12 PM

Thanks for setting all of that straight for me. I think I have a better understanding, and although I can see that the hydrometer should be used with a 'grain of salt', I feel more comfortable now knowing that the beer is sitting in a normal range around 5%. I didn't have a lot of action in the carboy, so I was a bit nervous, and this sets me at ease. But, I tasted the brew, and it is pretty darn good. Not quite as sweet as I had hoped for, but it smells fine (I was a little concerned about contamination), the colour is nice, it cleared well, and it has a hoppy bitterness and aroma that is pleasant. I'm pretty excited to see what it will taste like after sitting in the bottles for a month!

Thanks again,

Rob

**Walker** · 04-21-2006, 06:28 PM

Quote:

Originally Posted by rjm

I'm pretty excited to see what it will taste like after sitting in the bottles for a month!

I'm wondering if there will be any left 1 month after bottling.

I swear to god, my first batch was in the bottles for 14 days before we sampled it, and it was gone 2 days later.

cweston · 04-21-2006, 06:32 PM

Quote:

Originally Posted by Walker-san

One final thing... I don't believe the recipe when it states that the estimated startikng gravity is 1.050 and the estimated abv is appx 5.7%. You would need to have a finishing gravity of 1.006 (dropped from the original 1.050) to hit that abv target, and 1.006 is a VERY low gravity and would be a very thin beer.

Perhaps the 5.7% was abw and not abv?

A good rule of thumb, I think...

OG of 40 or less: low alchohol session beers
41-55: "standard" (standard macro swill is usually around 45, I believe)
55-75: stronger beers
above 75: very strong "imperial" level beers

**Walker** · 04-21-2006, 06:34 PM

Quote:

Originally Posted by cweston

Perhaps the 5.7% was abw and not abv?

A good rule of thumb, I think...

OG of 40 or less: low alchohol session beers
41-55: "standard" (standard macro swill is usually around 45, I believe)
55-75: stronger beers
above 75: very strong "imperial" level beers

abw will be LOWER than abv (since the density of alcohol is < the density of water).

to get 5.8% abw, you would need about 7.5% abv.