Hydrometer reading way lower han expected. Ideas?

Before i bottled the beer i took a hydrometer reading. It came out at around 1-2%. This is the brewers best beer kit American Light. It should have been around 4.2 to 4.5%.

after it boiled and cooled down to about 70 degrees, it was exactly at 5%

Fermented for about 6 days and in the second stage ferment for about 6 days.

Any ideas on why the % alcohol was so low?

You shouldnt ever use the % measurements. What you need to read are the specific gravity measurments. I am assuming your beer fermented low to the point that the projected ABV AFTER FERMENTATION would be 1-2%...not the current value

So if it started at 5% that would be about 1.038 gravity on the hydrometer. If it finished at 2% that would be about 1.013 gravity.
So take the 5% - 2% and you have yourself a 3% brew in the end. Sounds a bit low. Your starting gravity should have been higher I think.

My hydrometer has multiple scales on it as well. You'll have to take 2 measurements (before the yeast is picthed and post fermentation) to get a proper ABV reading. I personally have never used the % scale so I'm not sure if it can be read the same way but if you subtract your FG from your OG (using the scale that has 1.000 for water) and multiply by 131 you'll get your ABV.

damn, thats right. i forgot you have to do a little math. it was 1.042 when when i started.

before i bottled it was 1.016.

what could i have done or what needs to be done in the future so it comes out a little higher than what i made?

Hudson I have never done that but just did it with his and it works. Came out to 3.2%.
I have always done it the other way.
Nice tip.

what could i have done or what needs to be done in the future so it comes out a little higher than what i made?

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That's a really open ended question.

If you want higher ABV, my first suggestion would be to try another style of beer besides American Light.

So it looks like you ended up with about 3.5%.
I'm not familiar with those kits. Did the instructions include the target gravities for the OG and FG??

brewd00d said:

damn, thats right. i forgot you have to do a little math. it was 1.042 when when i started.

before i bottled it was 1.016.

what could i have done or what needs to be done in the future so it comes out a little higher than what i made?

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Hard to say without knowing a bit more info... if it was an extract batch, then more DME/LME = More sugar = Higher starting gravity. (generally speaking, but it may or may not be appropriate per se)

Also, make sure you're using ALL the extract. If it's Liquid extract, put the container in a hot water bath to help get all the LME in your water and/or rise it with some of the hot wort to get all the extract out of the container.

If you're doing a partial boil, don't over-dilute (add to much water after the boil)...

Only 12 days, maybe it wasn't finished. If it was supposed to finish at 1.010 it would have been right on 4.2%

brewd00d said:

Before i bottled the beer i took a hydrometer reading. It came out at around 1-2%. This is the brewers best beer kit American Light. It should have been around 4.2 to 4.5%.

after it boiled and cooled down to about 70 degrees, it was exactly at 5%

Fermented for about 6 days and in the second stage ferment for about 6 days.

Any ideas on why the % alcohol was so low?

Click to expand...

Did you do a full boil originally, or did you add some water afterwards (partial boil) ? If the latter, it is possible [likely] that it wasn't mixed fully, and your OG reading was still inaccurate.

I wouldn't recommend using the % potential alcohol scale- use the other scale (usually .990-1.170 or so) and do calculations based on that. Also, be sure that you're reading the level at the bottom of the meniscus, not where the wort/beer touches the hydrometer. And lastly, these things are pretty inaccurate if you put hot wort in them (just fyi, yours wasn't hot at 70F). I think most of them are calibrated at 60F, so even at 70F, you can do a correction up to 1.039 from 1.038@70F.

I'd definately wait a bit longer next time. I've done a few beers with a similar OG and the FG has always been below 1.010, it's possible that the ABV/gravity was so low because fermentation wasn't complete.

hudsonj6 said:

I'd definately wait a bit longer next time. I've done a few beers with a similar OG and the FG has always been below 1.010, it's possible that the ABV/gravity was so low because fermentation wasn't complete.

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It really depends. If you're making batch with liquid extract that's been sitting on the shelf for a long time, or you boil for a long time,etc. you end up with a less fermentable wort and a higher FG. And that's not even getting into the yeast used, fermentation temperatures, etc.

That's why I said it's an open ended question. There's so many potential reasons that it's really difficult to enumerate them all.