Author Topic: finishing gravity for wlp800?  (Read 283 times)

Offline Homebrew_kev

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finishing gravity for wlp800?
« on: January 18, 2021, 08:57:39 PM »
I have a german pils that came out around 1.022 with wlp800 - Beersmith says estimated final gravity is 1.013. My gut says that's a little high, did a diacytal rest, and it tasts good. I can't pick up too much sweetness because I gave it a solid bittering addition. I'm really happy with out it came out, but I'm not sure if my hydrometer isn't calibrated right or if there was somthing else going on during fermentation?

I used a 1L starter, nutrient, and pure O2 with the Blichmann inline areator (first time using it) - fermentation kicked off real quick (less than 24 hours). I let it go at 55f for about 1.5 weeks then bumped up the temp to 65 for another week. Crashed cooled it at 33f for about 2 weeks before i kegged it.

I'm overall happy with the beer.

Starting gravity came in around 1.051 so if my readings are right - i'm looking at a 6% beer?
« Last Edit: January 18, 2021, 09:05:28 PM by Homebrew_kev »

Offline ynotbrusum

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Re: finishing gravity for wlp800?
« Reply #1 on: January 18, 2021, 09:01:32 PM »
What device are you using to measure the FG?  Many have made the mistake of using the refractometer without adjusting for alcohol present in the final sample.  A hydrometer is indispensable if you don't use the adjustment calculation for your hydrometer.  You may well be at 1.012 or less.  Ignore the foregoing, if you are using a properly calibrated hydrometer at the proper temperature.
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Offline Homebrew_kev

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Re: finishing gravity for wlp800?
« Reply #2 on: January 18, 2021, 09:04:25 PM »
I'm using a hydrometer to measure final gravity. I used a refractometer for the origional gravity. One of my goals this year is to get better at taking readings. I've seen the EasyDen and that looks helpful - I hate to take readings, I can never really tell where the liquid meets the line!

I calibrate my refractometer every time I brew - pretty easy to do with distilled water.

Offline Saccharomyces

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Re: finishing gravity for wlp800?
« Reply #3 on: January 19, 2021, 03:05:15 AM »
I used a 1L starter, nutrient, and pure O2 with the Blichmann inline areator (first time using it) - fermentation kicked off real quick (less than 24 hours). I let it go at 55f for about 1.5 weeks then bumped up the temp to 65 for another week. Crashed cooled it at 33f for about 2 weeks before i kegged it.

A 6% ABV beer usually has a starting gravity of at least 1.060 and that is with a yeast strain that is capable of 77% apparent attenuation.  Working backward from ABV to attenuated gravity points, we get 6 / 1.25 = 4.8 ABW (alcohol by weight).  Coverting ABW to attenuated gravity we get 4.8 / 105 = 0.046 (0.0457 rounded up).  Now, converting attenuated gravity to O.G., need to divide this value by apparent attenuation.  Let's say that a yeast strain is capable of 77% apparent attenuation.  Diving 0.046 by 0.77 yields 0.060 (rounded from 0.0597).  Working the other way, (O.G. - F.G.) * 105 * 1.25, (1.060 - 1.014) * 105 * 1.25 = 6%.

Offline tommymorris

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Re: finishing gravity for wlp800?
« Reply #4 on: January 19, 2021, 03:02:07 PM »
I'm using a hydrometer to measure final gravity. I used a refractometer for the origional gravity. One of my goals this year is to get better at taking readings. I've seen the EasyDen and that looks helpful - I hate to take readings, I can never really tell where the liquid meets the line!

I calibrate my refractometer every time I brew - pretty easy to do with distilled water.
You can mix a solution of table sugar and water to test your hydrometer at the lower end of the spectrum of specific gravity.

4 grams sugar + 96 grams water is a 4% Brix solution which should have a 1.016 SG. 3% Brix (3g sugar + 97g water) should read 1.012.

I tested my hydrometer and found it to be off a few points on the low end. I bought one specifically for measuring finish gravity. When mine was off I was confused because the beers didn’t taste sweet. They were actually quite good. My taste buds were right.

Offline ynotbrusum

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Re: finishing gravity for wlp800?
« Reply #5 on: January 19, 2021, 03:11:24 PM »
A couple years back I went with a lab grade final gravity hydrometer for better verification.  Even so, I use it sparingly, because I fear breakage (and I use a Tilt Hydrometer usually to tell me when there is no change in gravity over a few days) but it is so much easier to read with the limited range (.980 to 1.020).

To the OP - if you are happy with the beer, I wouldn't let the numbers bother you, but it seems that a low end calibration would be in order for your hydrometer, as suggested above.
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Offline spurviance

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Re: finishing gravity for wlp800?
« Reply #6 on: January 19, 2021, 03:50:03 PM »
I agree.  Bottom line is how the beer tastes.  That's the ultimate goal.  I too love the science aspect and try to hit the numbers as close to predicted to ensure that my process is correct.  Good advice above on calibration tips.
How about mash temp?  I didn't see that mentioned.  Perhaps if you mashed in the upper 150's your wort wasn't nearly as fermentable as it could have been which would lead to lower yeast attenuation...
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Offline Homebrew_kev

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Re: finishing gravity for wlp800?
« Reply #7 on: January 19, 2021, 11:41:41 PM »
I'm starting to wonder if I didn't let it ferment all the way. After racking in to the keg, I left the carboy with the airlock still on it in the garage - and today i see some foam, kind of like krausen. I'm going to take the keg out of the cooler and let it sit at room temp for a day or two.

after many batches, I'm still to impaitent!