F.G. went ?UP? during lagering

[johngaltsmotor]

I just transferred my 1st AG lager (1st AG, 1st lager) from lager carboy to keg yesterday. (it already tastes great even though under carbonated)

Question: going into the carboy SG was 1.014 - 6 weeks of lagering later (between 30F and 50F) FG is now 1.018....

Is that realistic? Or were there bubbles resulting from transfer on the hydrometer that made it float a bit higher? I can't think of how the SG would go up during lagering.

 

[Yooper]

You're correct- the SG can't possibly go up. One of the readings is wrong. Check the hydrometer in 60 degree water to see if the hydrometer is reading ok.

 

[LVBen]

I just transferred my 1st AG lager (1st AG, 1st lager) from lager carboy to keg yesterday. (it already tastes great even though under carbonated)

Question: going into the carboy SG was 1.014 - 6 weeks of lagering later (between 30F and 50F) FG is now 1.018....

Is that realistic? Or were there bubbles resulting from transfer on the hydrometer that made it float a bit higher? I can't think of how the SG would go up during lagering.

Are you measuring with a hydrometer and adjusting for temperature? The hydrometer is accurate at 60 degrees. Anything above that and you need to add to your measurement. Anything below that and you need to subtract from your measurement.

 

[rycov]

did you adjust for the cooler temp?

 

[barrooze]

This is the hydrometer adjuster calculator I like to use:

http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html

 

[lumpher]

for the 83rd time... nope, i won't ask about adjusting for temp

 

[ajf]

There are 3 possibilities I can think of.
1. CO2 can affect the reading. I took a reading of an ale yesterday. It was 1.020 (much too high). I spun the hydrometer for a few minutes to shake off the bubbles, and the gravity reading dropped to 1.014.
2. You added priming to the carboy. This will increase the gravity a bit.
3. Temperature. You may want to take a reading at the wrong temperature and apply temperature compensation, and then cool or warm to 60F and check again. This will give you an idea as to how accurate/inaccurate temperature compensation can be.

-a.

 

[LVBen]

for the 83rd time... nope, i won't ask about adjusting for temp

??????

 

[LVBen]

Oh nevermind... I understand... you've seen about 83 of these threads.

 

[johngaltsmotor]

Wow, talk about an impressive response. Thanks everyone.

A temperature correction would only drop it by .001 at most, not nearly the .004 it went up (I didn't pay close attention to the temperature before transfer).

Because it is a Schwarzbier and I simply put the hydrometer in the keg, not a sampling cylinder, I couldn't see how many bubbles were on it to affect it - I supposed in the future I'll always give it a spin to shake them lose. Now that it's been force carbonated I can't really go back and measure again.

I didn't see any way based on my understanding of the laws of chemistry for it to go up, but I figured I'd ask. I don't really mind, I'm just trying to take notes all along the way for future reference and was a bit puzzled.

 

[weirdboy]

Is the volume the same? If you lost some volume due to evaporation that might help explain it.

 

[LVBen]

Wow, talk about an impressive response. Thanks everyone.

A temperature correction would only drop it by .001 at most, not nearly the .004 it went up (I didn't pay close attention to the temperature before transfer).

Because it is a Schwarzbier and I simply put the hydrometer in the keg, not a sampling cylinder, I couldn't see how many bubbles were on it to affect it - I supposed in the future I'll always give it a spin to shake them lose. Now that it's been force carbonated I can't really go back and measure again.

I didn't see any way based on my understanding of the laws of chemistry for it to go up, but I figured I'd ask. I don't really mind, I'm just trying to take notes all along the way for future reference and was a bit puzzled.

So, you didn't adjust for temperature? I don't know what temperatures you measured at, but based on the link posted above:
1.018 @ 35 = 1.017
1.014 @ 75 = 1.016

The corrected amounts are only off by 0.001, which is easily explained by human error.

 

[johngaltsmotor]

no, I meant that both were 50-55F so I didn't bother to adjust, the calibration table that came with the hydrometer lists .0005 as the correction factor for 50F vs 60F so it's not a noticeable factor even if I was off by 10deg.

If it was .001 to .002 I'd say it was a combination of errors, but .004 just seemed high. I'll attribute it to bubbles from transfer that stuck to the hydrometer as it was lowered in.

I guess it's just an indicator that I should shell out the $45 and get a refractometer

(whatever the case, it's still great beer)