Beginner--Need a good abv measurer

You need a hydrometer. Most are pretty cheap. But you needed to take a measurement before fermentation for the reading after fermentation to be meaningful for computing ABV.

 

You should be able to get a hydrometer for less than $10, although my first one came as part of a larger equipment kit and not by itself. You might look into a kit depending on what equipment you already have. There are often online sales.

Once you have that, you can calculate ABV with gravity readings taken before and after fermentation is finished, like Vikeman says. There are free ABV calculators online, as well as ones in books.

 

Did the instructions for your kit mention an expected Original Gravity (OG) reading and a Final Gravity (FG) reading? I seems to me that it would be unusual if that info was not there, but if the instructions did not mention a target ABV, well then maybe the kit was not so helpful with what you will get once the beer has been brewed and that left you on your own.

If you do have the expected OG and FG readings from the recipe then you can use a couple of different formulas to calculate the approximate ABV. I'm traveling and away from home right now so I don't have those formulas available to give to you, but someone else can chime in on that, or you can easily google a search and find them. But those formulas assume that you do have the kit's expected hydrometer readings. Without that info the only other way is an expensive meter that can measure the ABV in the finished beer.

 

Any self-respecting homebrew supply should give you a hydrometer (even for an extract beginner equipment kit).
Having said that...buy one...and then more importantly...buy this or view on-line: "How to Brew" by John Palmer (Chapter 9, "Fermenting Your First Batch"...page 98)...cheers and welcome to the obsession.
Austin, Rebel, and BrewMasters Warehouse are probably your closest on-line suppliers.

 

After getting an OG and FG

http://www.howtobrew.com/section1/chapter9-4.html

and

http://www.brewersfriend.com/abv-calculator/

 

(OG - FG) * 131
As Mothergoose03 said, the instructions should tell you the expected values. OG should be spot on. If the beer tastes like ...well, beer, then it probably finished pretty close to the expected FG. This formula will be close enough.

This, of course, assumes you used malt extract. All grain is a little more sensitive to technique/process/

 

Was it an extract batch? If so, you could provide the recipe and final volume of wort before pitching your yeast, and we could give you an approximate original gravity. Then buy a hydrometer and take a final gravity reading. Use mikehartigan's formula, and that will at least get you in the ballpark.

 

http://www.howtobrew.com/section1/chapter9-4.html

No math required : )...and a great book as you progress in your brewing Cheers

 

Unless he guesstimated how much volume he had in the bucket/carboy as 5 gallons and actually has 4.35 or 5.6 gallons, in which case his OG would be much higher or lower than expected, which would raise or lower the ABV. No offense to the OP, but if he didn't know what a hydrometer was I suspect he didn't calibrate his equipment before brewing, and if the kit didn't come with a hydrometer included, I suspect the brew shop didn't calibrate them either.

EDIT: I say this for the OPs info, as Mike already knows his stuff

 

You're right. I should have qualified my comment with "Assuming the volume of wort was what was specified in the recipe...", or words to that effect.

And you're right - I already know my stuff! And yet, there's so much more to learn. I'm of the opinion that, once you know everything there is to know about a subject, it's time to move on. I pray that I never know everything there is to know about brewing beer.

 

Well, without a hydrometer, you won't really know if your beer has finished fermenting before you bottle it. Which is kind of important.

 

What did you ferment it in? 5 gallon carboy, 6 gallon carboy, 5 gallon bucket, 6.5 gallon bucket? What was the ABV (or even the OG) supposed to be from the recipe?

 

6 gallon carboy would lead me to believe you are somewhere in the correct range for the volume. Leave the beer alone for 3 weeks to be sure. That is the rule that many of us follow, 3 weeks primary ferment, 3 weeks bottle. I would assume that you have around the same ABV as the recipe, give or take. If it was for a 5.3% beer, you are probably somewhere in the 4.8% to 5.8% range, if I were to wager a guess.

 

If you're not going to get a hydrometer (get one), I'd recommend waiting 3-4 weeks, then bottling. First, you'll greatly increase the odds that attenuation is finished. Second, you'll give the yeast time to clean up off flavors.

 

Yep. The only way quantitative way to know how your fermentation is progressing is by measuring gravity.

No. Airlocks are not a good quantitative indicator. You were right the first time with the hydrometer advice.