My brewing skills are getting slowly better. But I'm still so anxious about contamination and eager to pitch the yeast that I haven't yet used my hydrometer. I realize this is crucial to good brewing.

Is there a practical way to measure the ABV of a brew without having the OG value for calculations? I was wondering if I could measure out a precise amount (with a graduated cylinder?), take the specific gravity, evaporate the alcohol with heat and then add water to bring the sample back to original volume for a SG comparison. I'm not a chemist so I don't know if this would work.

I realized I hadn't taken the OG for my last batch just after the yeast was pitched. Plus cooling the wort had taken too long--must do better next time.

Edit:
I just added an ABV Calculator to the site. It's pretty simple, all you do is enter the starting gravity and final gravity and the ABV gets displayed. Feel free to check it out.

Tag:
How to measure ABV in beer, abv calculation beer, calculate accurate abv, beer brewing og, find abv homebrew, og abv table

It takes a few hours for the yeast to really start doing much so you can take it after the yeast is in. I would say to not worry about it too much. If you have a rough idea of the starting gravity just take a final gravity reading & estimate it that way. As long as you reach your target gravity or close to it you are good to go with bottling. & evaperating the alcohol would not work because it comes from the sugar that the yeast have converted so your reading would be way low.
All the hydrometer is seeing is sugar content. So just estimate & be done.
Like everybody says!! "dont worry,relax, have a homebrew"!! I forget to take readings all the time. I also forget to put in all of my hops sometimes too. Just write down everything you did so if you stumble on something great you cn make it again!!

after my wort is cooled, when i transfer to the fermenter, i run the first pint into a container to make sure it is running clear with not too much junk then i splash the rest into the fermenter. i then have a sample to check the gravity and the hop taste and figure the abv when ferment is done.
gary

If you are brewing with extract, it should be pretty easy to figure out what your OG should have been, and should be fairly consistent batch to batch. If you are all grain brewing, you can use the bit of fluid left over at the bottom of your boil pot (with the trub) to get your OG. This way, you can cool your wort and pitch your yeast, and still be able to take an accurate OG reading. I usually use this approach, because I am loathe to waste good wort on an OG calculation, seeing as how I won't put that wort back into my fermenter (as a safety precaution). Also, I tend to end up with the perfect amount of wort left over with my trub for a gravity reading.

If you did an extract brew, and if you have an accurate count of the amount of wort you put into your fermenter, you can use a brewing program like beersmith or homebrew alchemist to figure out what your OG was. Since extract brewing doesn't need to calculate for efficiency, the results should be pretty damn accurate.

Hope this helps!

Cheers
Dave

Thanks for all the great advice!

It was a recipe kit with extracts and steeping grains. So maybe I could calculate it out. That would be a good learning
exercise in itself.

Good brewing,

Jim

Good deal. So, let me ask you:

How much/What type of extract(s)
How much/What type of specialty grains
How many gallons of wort did you end up with in your fermenter?

If you don't already have some brewing software, you can download the Homebrew Alchemist here:
homebrew-alchemist-now-available-t849.html

Cheers
Dave

Dave, Should be the following:

1/2 lb. 90L steeping grain, soaked 20 minutes at 155 deg
1 lb. extra light DME
1 lb. corn sugar
1/4 lb maltodextrin (izzat right ?)
5 lb. Amber LME

Amarillo hops, 0.75 oz. at start of 60 min. boil, .25 oz for last 5 min.

Total volume: 5 gallons

You can get a ballpark from an extract batch like Dave says. You do have to take into consideration the extraction you obtain from the steeping of the grains, the crush of those grains. The manufacturer of the extract will affect the gravity as well but they are all fairly close. Yeast type/attenuation will play a factor as well. The suggestions give about using that bit in the bottom of the pot is a very good way to get some work for gravity. I myself use a refractometer with an easily saitizable glass eye dropper or sometime use a pipette. I also have a glass wine thief that is easily able to sanitize. If you sanitize what ever you draw the work sample with you should be just fine as you don't want to add that sample bask into the batch. I will add that the few extract batches I have made I never measured anything. They were premade kits that I I dumped it in the pot, boiled it, cooled it, fermented it, kegged it, drank it.

Bierbelly wrote:Dave, Should be the following:

1/2 lb. 90L steeping grain, soaked 20 minutes at 155 deg
1 lb. extra light DME
1 lb. corn sugar
1/4 lb maltodextrin (izzat right ?)
5 lb. Amber LME

Amarillo hops, 0.75 oz. at start of 60 min. boil, .25 oz for last 5 min.

Total volume: 5 gallons

That should put you right in the 1.056 range. After the beer is done fermenting, you can get a final gravity reading and make an ABV estimate. FWIW, maltodextrin should give 40 points of gravity per pound per gallon. I made a note of it because maltodextrin does not appear in either Beersmith or Homebrew Alchemist.

Hope this helps!

Cheers
Dave

FWIW, maltodextrin should give 40 points of gravity per pound per gallon. I made a note of it because maltodextrin does not appear in either Beersmith or Homebrew Alchemist.

Hope this helps!

Cheers
Dave

It is in the Misc. list of ingrediants in Beersmith

Dang, that screenshot didn't format good.

Thanks Dave! That helps to get my bearings. This is my first batch with steeped grains, so I have high hopes.

Swampwater Brewing wrote:It is in the Misc. list of ingrediants in Beersmith

Hey, thanks! I didn't see that before. The only problem is, if you use Maltodextrin from the Misc. section, it won't show an increase in your gravity....

Cheers
Dave