# ABV Issue - How to tell apart batches?

So, is there a way to determine alcohol content of the beer if you mixed up two batches? I have two unlabeled batches, and don’t know which is which, anymore…

I’ve got a “milk chocolate” stout and a russian imperial stout, both in secondary. The RIS is about a month older. They visually appear identical (in the secondary, that is). One has much stronger aroma, but otherwise the aromas for the two are similar in character. I added the cacao nibs (and the few ounces of plain vodka in which they were soaking) to the stronger aroma beer–guessing that it may be the “younger” milk chocolate stout, but now am having second thoughts. I’m about to hit the other carboy with cacao nibs just in case, but I’d still prefer to know which is which, for competition purposes.

So, is there a way I can determine the alcohol content of either of these? The RIS is–or should be–about 9.5%. I did take its OG and gravity upon transfer to secondary. The milk chocolate stout should be about 5.5%, though I haven’t taken a FG reading (and did add a bit of alcohol to it by way of the vodka).

I don’t see why you can’t. I would assume the higher ABV is the RIS. I wouldn’t worry about the little bit of vodka you added as there wasn’t enough to increase the ABV much.

If you have a refractometer, you can calculate percent alcohol by taking a reading with the refractometer and also measuring the FG with a hydrometer. I don’t know of any way you could tell which is which with only a hydrometer, because to calculate alcohol that way you need to know OG, which means you already know which is which.

If you don’t have a refractometer, you can probably tell which is which by taste.

Maybe I’m missing something in your suggestion. I do have the OGs for each, but I don’t know which OG corresponds with which carboy. I do have a gravity reading for the RIS, but it was upon transfer to secondary, and could have dropped since then. I could grab current (FG) gravities, but I did add maybe 2-3 oz of vodka to one batch. Do you suggest I try taking the FGs and see which is closest to the RIS gravity I took upon transferring to secondary? That’s all I’ve thought up on my own; does anyone know of any other method?

I do have both… though I’ve almost never used the hydrometer since I got the refractometer. How does this work? How does this tell you the ABV?

One more thing, I just now noticed you said you took a gravity of the RIS at secondary. It shouldn’t have changed much. So if you’re lucky the two beers now have different final gravities, and the one that most closely matches the gravity you took at transfer is probably the RIS.

If you’re not lucky, the two beers will have pretty close to the same FG, and you’re back to needing a refractometer. Good luck.

My guess is that the RIS would not finish as low as the lower gravity stout.

My guess is that you reversed the two and that the stronger smelling one was the RIS. What was the OG?

[quote=“560sdl”]My guess is that the RIS would not finish as low as the lower gravity stout.

My guess is that you reversed the two and that the stronger smelling one was the RIS. What was the OG?[/quote]

RIS OG was 1.100. Milk Chocolate Stout OG was 1.063. I’m getting a roll of masking tape and labeling this stuff going forward… I feel stupid.

Have you tried tasting them? If one is twice as strong as the other, I would think you’d know after sampling a tablespoon of each.

Full disclosure: “Consume beer” is my answer to a lot of issues so take it with a grain of salt.

I do have both… though I’ve almost never used the hydrometer since I got the refractometer. How does this work? How does this tell you the ABV?[/quote]

Its the same basic concept of needing to use an equation to correct for the presence of alcohol, but instead you work backwards. Once alcohol is present a refractometer reading by itself doesn’t tell you anything. If you know the OG (taken by either hydrometer or refractometer, doesn’t matter) you can calculate FG and thus alcohol. If you DON’T know the OG (which is your case since you don’t know which beer is which) but do know FG (which has to be measured by a hydrometer) you can back out what OG must have been and thus alcohol.

But its easier than I make it sound. Just use this online calculator. http://www.musther.net/vinocalc.html#alcoholcalculation

Take a sample, measure SG with hydrometer, measure brix with refractometer, and input into calculator. It will spit out percent alcohol.

[quote=“Silentknyght”][quote=“560sdl”]My guess is that the RIS would not finish as low as the lower gravity stout.

My guess is that you reversed the two and that the stronger smelling one was the RIS. What was the OG?[/quote]

RIS OG was 1.100. Milk Chocolate Stout OG was 1.063. I’m getting a roll of masking tape and labeling this stuff going forward… I feel stupid.[/quote]

Don’t feel bad, I have done this a few times. One time I forgot to label the fermentors (ok, maybe 3 times) and have also forgot to label the yeast when I harvest two batches on the same day and put in the refrigerator. I have poured out several quarts of perfectly good harvested yeast because I had no earthly idea which batch it was from :oops:

I have not used a refractometer, but could you deduce which is which by the process of elimination? You have two OGs. Take a sample from one of the secondaries. Using your refractometer calculate ABV using one OG and then recalculate using the other OG. One of the calculations should be close to the estimated ABV and the other way off. Do the same with a sample from the second secondary.

[quote=“Silentknyght”][quote=“560sdl”]My guess is that the RIS would not finish as low as the lower gravity stout.

My guess is that you reversed the two and that the stronger smelling one was the RIS. What was the OG?[/quote]

RIS OG was 1.100. Milk Chocolate Stout OG was 1.063. I’m getting a roll of masking tape and labeling this stuff going forward… I feel stupid.[/quote]

[quote=“Meerts”]Have you tried tasting them? If one is twice as strong as the other, I would think you’d know after sampling a tablespoon of each.

Full disclosure: “Consume beer” is my answer to a lot of issues so take it with a grain of salt. [/quote]

If you can’t tell the difference by tasting these 2 beers, you are wasting your money on making high ABV beers.

Since he has a refractometer, he may as well go through the exercise of measuring alcohol that way just for the experience. But yeah, I would assume you can tell them apart by taste.

[quote=“Nighthawk”][quote=“Silentknyght”][quote=“560sdl”]My guess is that the RIS would not finish as low as the lower gravity stout.

My guess is that you reversed the two and that the stronger smelling one was the RIS. What was the OG?[/quote]

RIS OG was 1.100. Milk Chocolate Stout OG was 1.063. I’m getting a roll of masking tape and labeling this stuff going forward… I feel stupid.[/quote]

[quote=“Meerts”]Have you tried tasting them? If one is twice as strong as the other, I would think you’d know after sampling a tablespoon of each.

Full disclosure: “Consume beer” is my answer to a lot of issues so take it with a grain of salt. [/quote]

If you can’t tell the difference by tasting these 2 beers, you are wasting your money on making high ABV beers. [/quote]
LOL that’s what I thought, too. Assuming you’ve been drinking your HB consistently you’ve built up a healthy alcohol tolerance. Drink 3 pint glasses of each in an hour one day apart. Record your results. Whichever makes you more drunk is the higher ABV! :cheers:

In the words of Cheech and Chong, “Taste!”

[quote=“mvsawyer”]
LOL that’s what I thought, too. Assuming you’ve been drinking your HB consistently you’ve built up a healthy alcohol tolerance. Drink 3 pint glasses of each in an hour one day apart. Record your results. Whichever makes you more drunk is the higher ABV! :cheers: [/quote]

1.100 beer v. 1.063 beer is a 10% beer v a 6% beer. You should be able to tell the difference between them with a 1oz sample.

[quote=“Nighthawk”][quote=“mvsawyer”]
LOL that’s what I thought, too. Assuming you’ve been drinking your HB consistently you’ve built up a healthy alcohol tolerance. Drink 3 pint glasses of each in an hour one day apart. Record your results. Whichever makes you more drunk is the higher ABV! :cheers: [/quote]

1.100 beer v. 1.063 beer is a 10% beer v a 6% beer. You should be able to tell the difference between them with a 1oz sample.[/quote]

You think so? This is on the backs of my club’s “Strong Beer Competition” (7%+ ABV only). There were several that seemed downright sessionable… I think taste can be deceiving. I actually think Sawyer’s test would be a better gauge!

At any rate, I’ll do the combo hydrometer + refractometer test tonight, and also taste & see.

So, here’s what I got: hydrometer reading of 1.020 SG and refractometer reading of 9.0% brix. This is the beer to which I added the cacao nibs. Plugging this into the “Original Gravity of Finished Beer” calculator within beersmith, it spits out a result of 1.061 OG. This is pretty close to the estimated 1.063 OG for the milk chocolate stout. Looks like I guessed correctly!

For kicks, I tried it with the RIS. 1.030 and 13.8% Brix. Calculates to an OG of 1.098, which is close enough to the 1.100 originally measured.

Also, yes, I was able to discern the two by taste, but only really because of the noticeable alcohol in the RIS (these are not carbonated, remember).

Cheers & thanks for the help. Cool to learn a practical use for my hydrometer!
:cheers:

Did you taste them before taking the readings so as to not “taint” the lineup?