SG of finished beer

Get advice on making beer from raw ingredients (malt, hops, water and yeast)
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guypettigrew
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SG of finished beer

Post by guypettigrew » Fri Jul 27, 2018 2:44 pm

What gravity is your finished beer? By which I mean the stuff you're drinking, not the stuff in the FV at the end of the primary fermentation.

Mine's about1.004-1.006.

Seems very low, but perhaps it's right. I don't have the nerve to call into my local with my hydrometer and measuring cylinder!

If it's too low it suggests my mash technique isn't all it could be.

Thanks.

Guy

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Jim
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Re: SG of finished beer

Post by Jim » Fri Jul 27, 2018 3:47 pm

I've never tested the beer in my glass, but I'm not surprised by your findings. The yeast carries on working (slowly) all the time.
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Kingfisher4
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Re: SG of finished beer

Post by Kingfisher4 » Mon Jul 30, 2018 2:50 pm

Coincidently, I did exactly the same thing with my most recent two Brews when they seemed much too gassy for the final gravity and tiny amount of priming sugar.

They were also 1.006 and 1.004 having been bottled at 1.012 and 1.010. I have assumed that the horrible hot weather for the last six weeks raising the temperature in my usually very cool garage has accelerated the continuing fermentation in the bottles.

Yet another variable I have to get my head around, in the absence of any brew fridge!!

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Re: SG of finished beer

Post by Robwalkeragain » Mon Jul 30, 2018 5:11 pm

After OG, yeast has probably the biggest influence on FG. Windsor doesn't utilize maltotriose at all, saison yeast will chew through almost everything, so the same beer can finish at 1.004 or 1.015 depending on what you choose. What yeast are you using? If you're mashing around 68 have you calibrated your thermometer?

guypettigrew
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Re: SG of finished beer

Post by guypettigrew » Tue Jul 31, 2018 9:08 am

The yeast was Whitelabs WLP 001. Mash temperature read as 66C. I was using a new digital thermometer because my old one gave up the ghost during the previous brew. Never thought to calibrate it. In fact, I don't think it can be calibrated!


Guy

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Re: SG of finished beer

Post by Robwalkeragain » Tue Jul 31, 2018 9:48 am

Make up some ice water, leave for 5 mins and dunk the probe in. It should be 0c, just adjust for any difference. Mine has been reading at +2c fairly consistently

guypettigrew
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Re: SG of finished beer

Post by guypettigrew » Tue Jul 31, 2018 10:41 am

Robwalkeragain wrote:
Tue Jul 31, 2018 9:48 am
Make up some ice water, leave for 5 mins and dunk the probe in. It should be 0c, just adjust for any difference. Mine has been reading at +2c fairly consistently

Does this mean, in your case, that you subtract 2C from all your readings? As far as I can see my thermometer has no calibration screw.

Have you tried yours in boiling water?

Guy

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Re: SG of finished beer

Post by Meatymc » Tue Jul 31, 2018 11:27 am

Jim wrote:
Fri Jul 27, 2018 3:47 pm
I've never tested the beer in my glass, but I'm not surprised by your findings. The yeast carries on working (slowly) all the time.
Hmmmmmmmm.......never occured to me to test the final result in the glass either.

Might give that a go tonight to see what the latest 6.5% IPA actually is when consumed. And of course, to get some meaningful data, I better check several bottles of both the same and different batches just to be a bit more scientific about it and in case any particular one gives a false reading.

The things I do for the sake of research :wink:

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Re: SG of finished beer

Post by guypettigrew » Tue Jul 31, 2018 2:10 pm

Meatymc wrote:
Tue Jul 31, 2018 11:27 am

Hmmmmmmmm.......never occured to me to test the final result in the glass either.

Might give that a go tonight to see what the latest 6.5% IPA actually is when consumed. And of course, to get some meaningful data, I better check several bottles of both the same and different batches just to be a bit more scientific about it and in case any particular one gives a false reading.

The things I do for the sake of research :wink:
You are a hero. Not many people would sacrifice themselves in this way for scientific research.

And good to see you understand the concept of variability in taking readings.

Please, let us all know what you discover.

Guy

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Re: SG of finished beer

Post by Meatymc » Tue Jul 31, 2018 9:44 pm

1st report.

4 pints in - 2 x IPA (different ages and dry hop additions but same basic recipe) a kolsch and a bitter. Consistent across the board all coming in 4 points below the final gravity reading pre-bottling. Within a couple of hundredth that puts an extra 0.5% on the original calculated alcohol content.

Right, that's the easy bit, now for the 2nd samples :shock:

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Re: SG of finished beer

Post by Robwalkeragain » Thu Aug 02, 2018 10:20 am

guypettigrew wrote:
Tue Jul 31, 2018 10:41 am
Robwalkeragain wrote:
Tue Jul 31, 2018 9:48 am
Make up some ice water, leave for 5 mins and dunk the probe in. It should be 0c, just adjust for any difference. Mine has been reading at +2c fairly consistently

Does this mean, in your case, that you subtract 2C from all your readings? As far as I can see my thermometer has no calibration screw.

Have you tried yours in boiling water?

Guy
Yeah exactly that. I do mine every couple of brews, not tried boiling water, doesn't it boil at different temperatures depending on elevation?

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Re: SG of finished beer

Post by Eric » Thu Aug 02, 2018 1:26 pm

Robwalkeragain wrote:
Thu Aug 02, 2018 10:20 am
guypettigrew wrote:
Tue Jul 31, 2018 10:41 am
Have you tried yours in boiling water?

Guy
I do mine every couple of brews, not tried boiling water, doesn't it boil at different temperatures depending on elevation?
It does indeed depend upon atmospheric pressure and therefore height above sea level. That's not such a problem in UK as few live greatly above sea level, boiling point on the top of Ben Nevis is higher than it would be in Reno, Nevada. Even so, knowing barometric pressure it is possible to derive boiling point. You could consider putting some cheap vodka and a thermometer in a test tube in a pan of near boiling water and note when the reading slows to a virtual stop as the alcohol evaporates at around 78.2C.

My beers are often casked at 1012 to 1015 and has frequently been measured at around 1004 several weeks later and towards the end of the cask.
Without patience, life becomes difficult and the sooner it's finished, the better.

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