Low ABV

[m_rawdin]

So my latest brew was 1.050 before fermentation (which was a bit higher than I wanted) and I've just bottled it at 1.037, it fermented pretty well and I kept at a pretty much constant 20 degrees. This means the ABV is way off the 4.5% I was hoping for, anyone know why this might be?

[Matt in Birdham]

What yeast did you use? I wouldn't be bottling anything at 1.037 - that's barely started fermenting and I'd be extremely wary of those bottles after a couple of weeks. There's an awful lot of sugar still in there that is likely to ferment and create bottle bombs.

[m_rawdin]

Safale US-05 Yeast (11.5g), it had stopped fermenting before I left it conditioning in my garage for a couple of weeks. Might it be that it didn't fully stop fermenting? Is it going to carry on in the bottles then?

[hazelbrew]

agree with Matt. 1037 is way too high. if that carries on fermenting you are looking at really high pressure.

http://braukaiser.com/wiki/index.php/Ac ... arbonation

rule of thumb from here is every two gravity points gives you one atmosphere.

so if your bottles drop another 20 gravity points with time... you are looking at 10 atmospheres pressure ! and something tells me that is not going to end well...

and to put it in perspective... i am worried about bottling a beer at 1022... that has dropped down from 1052. target FG for the beer was 1016.

[m_rawdin]

Yeah I have a feeling I might have created some time bombs there! I'll see how they go over the next couple of weeks

[m_rawdin]

I now realise I need to do some calculations with the FV as I'm using a refractometer, my FV looks to me more around the 1.026 mark. This is still off my target FV but is better than I thought.

[Monkeybrew]

1.026 still seems very high for a beer that started at 1.050, especially when using S-05 yeast, which normally chews through gravity points

What ingredients were in your brew?

Cheers

MB

[BenB]

I wouldn't use a refractometer to measure FG as the alcohol impacts on the refractive index. There are bodge [ahem] sorry- adjustment calculators but they vary in result so what's the right one?? I use my refractomer for quickly testing the runnings and pre-boil samples. For OG and FG I'd go hydrometer. Hydrometer can be used during fermentation to monitor the change in reading but I'd still take a hydrometer on the FG. For one it gives a nice tasty sample that it would be a waste to throw away

Either you've got bottle bombs or one seriously chewy beer! You sure you didn't add a ton of maltodextrin not dextrose

PS most standard beer bottles will happily take 2.5 volumes, 3 might be pushing it for some. Above that you want thick wall bottles. So 10 volumes might be less of "will they" and more of a "when will they". If in doubt why not try uncapping one now and check the carb level. I'd do it outside though!

[injac]

Yeah getting a reading like that I would have tried rousing the yeast and increased the temp for a few days as sounds like fermentation stalled. Then if still no sign pitched fresh yeast. Have some goggles on when you open those bottles.

[WalesAles]

Have some goggles on when you open those bottles.

m,
And some Fins and a Snorkel!
You might be swimming in Beer!

WA

[orlando]

I now realise I need to do some calculations with the FV as I'm using a refractometer, my FV looks to me more around the 1.026 mark. This is still off my target FV but is better than I thought.

Are you sure about FV (fermentation vessel) do you mean SG (specific gravity)? Gently open a bottle and put some of the contents into a sample jar, let it go flat (so carbonation doesn't artificially lift the hydrometer) and then test the SG with your hydrometer. Do the same thing again with another bottle a few days later and you will have an answer about whether it is fermenting on in the bottle. If it is you have some choices. Bin the lot or, use a bottle opener to gently release excess gas and then use your capper to reseal. The latter is a PITA but if you want any chance to save the brew and keep beer off all the surfaces of the room they are kept in that's just about it.