Help with gravity

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owentp

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Ok.....using beer smith. Making a medium body wheat beer. States my expected pb Gravity should be 1.058. I got 1.056. I did not fee compelled to correct for the .002 points. During the boil, took a sample & corrected it for temp & it was 1.070. Final gravity should be 1.066. So I'm doing ok...right? Boil over, cooled & in fermenter, sample reads 1.052.

So can somebody tell me what happened here?
 
You are doing a partial boil no?

You topped off the wort with water in the FV to reach your targeted volume, no?

This will dilute the wort bringing the gravity down. Mixing well before taking a reading is needed. Not taking gravity measures of very hot samples is also a good idea if you value precision.

All seems to make sense to me.

Sounds like a well done brew by the numbers.

Maybe I'm not getting what you're saying.
 
I'm a little confused, did you end with a FG of 1.056 or 1.052?

Even with correcting for temp. You just are not going to be that accurate with a hydrometer, taking a sample reading at near boiling temperature. You would want to cool the sample to at least room temperature first.

Either way, you made a wort that will certainly ferment into a good beer. :)

What temp did you pitch your yeast at?
 
I did no top off. Full boil. My final gravity at room temp was 1.052. Called for 1.066. Pb gravity called for 1.058, I had 1.056. Supposedly your gravity should increase with the boil due to evaporation.
 
I did no top off. Full boil. My final gravity at room temp was 1.052. Called for 1.066. Pb gravity called for 1.058, I had 1.056. Supposedly your gravity should increase with the boil due to evaporation.

PB???

Usually that means partial boil. i.e.: Topping off the volume.

Then the numbers can easily be explained via measurement errors. Samples at the wrong temperature, at different temperature will only be as accurate as the correction algorithm used. Not accurate in other words, especially at very high temperatures.

The other possibility (remote), is that your wort chiller, if you used one, leaked

Take consistent and repeatable gravity readings at the right temperature and you will better be able to diagnose mash problems (conversion or lauter efficiency or both) or system errors unrelated to mash efficiency.

Pre Boil Gravity DSC03252.jpg

Original GravityDSC03273.jpg

Final GravityDSC03334.jpg
 
I think by pb he meant pre boil. So then the question is if you chilled it down to 60 or 70 depending on what temp you are supposed to be using your hydrometer.
As stated you're going to get a more precise measurement if you don't correct for the temp but at least get it down to about 70. Then the correction is only like .001. Did you cool you either preboil or mid boil reading? Or only correct for temperature? As stated those algorithms can get pretty far off the higher the temp. And at a certain temp they just don't work anymore. In other words just take the few minute to cool it down to the temp it should be read at. Also if you've taken a correct pre boil reading, there shouldn't be much of a reason to do a mid boil one. You should know preboil whether or not you're going to need to adjust the boil time or add extract, or proceed as planned.
Other than the idea about your chiller leaking water into the wort, the only other reason your post boil reading would be lower than your pre boil is if you topped off (which you didn't) or if your readings were off.
 
Supposedly your gravity should increase with the boil due to evaporation.
There is NO supposedly about it.
Evaporation during the boil removes water and leaves sugar behind, so gravity WILL increase during the boil.
Unless you added water after the boil accidentally (via the wort chiller suggestion) then you have a measurement error.
 
Yes...my pb means preboil. I ran some clean water through the chiller & there was maybe a small amount of water that came out prior to chilled wort but nothing excessive. I have had little issue with my other beers so that leads me to think that there is no chiller leak (Blichmann Therminator). Had a similar prob with same brew last time but thought it was that I used red wheat vs white wheat. I'll start cooling samples to normal calibration levels for now instead of correcting.
 
One other ridiculous thing to rule out.

You're not boiling with the lid on I presume.

Likely a stupid question on my part but just throwing it out there to rule it out.
 
Then the only viable answer is measurement error(s).

I measure gravity at 60F (samples and hydrometer cooled to 60F)

  • preboil gravity and volume in the kettle (tells you your mash efficiency)
  • post boil gravity and volume to the FV This is the O.G. (tells you your brewhouse efficiency)
  • final gravity
 
Even with correcting for temp. You just are not going to be that accurate with a hydrometer, taking a sample reading at near boiling temperature. You would want to cool the sample to at least room temperature first.

I disagree. In my 40 or so batches so far I've always measured at up to 80C and then corrected for temp with beersmith and it was always right. Also checked that with refractometer recently.

I have misread the hydrometer though several times which is what the OP might have done and which is why I always check twice now.
 
Something does not sound right with this..as others have stated, your gravity should increase post boil from a pre-boil reading..Not sure how you are making temp corrections when you take your readings, but I usually pull my pre-boil gravity as the wort is heating up and pull it again at flame out and write them down along with the temp I pulled them at.

I pull my last recorded (SG) reading when I pitch the yeast but I based on the flame out reading I pretty much know what its going to be once the wort is at pitching temps and its never dropped post boil like yours seems to have done..I honestly have no idea what happened unless the pre-boil reading and corrections were off initially...

Note - I use a refractometer so pulling a reading does not take more than a few drops of wort to get a reading..
 
Wll my HBT colleagues.....I figured out what happened because I caught it last night while making my Porter.

I have 1 pump for all 3 vessels w/a "T" & depending which valve is open where the pump pulls from. I was chilling my Porter & noticed it getting lighter. I stopped pumping to figure out what was going on. I noticed that my HLT valve was open. Fortunately I saved this one in time. I sacrificed .005 points on gravity but sure it will turn out fine. Mystery solved & now I know I'm not completely crazy that I did something wrong in my mash or boil!
 
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