Double Batch, Two Cubes, Two Different Og's

[megs80]

Hey all,

The other week I christened my new double batch system and have ended up with a strange outcome.
Once my boil had finished I stirred the kettle and let the junk settle for 15mins. After this, I drained two cubes worth of wort consecutivley. It was a simple recipe which didn't call for chilling. Beersmith estimated my OG was going to be around 1060, which was my target. Becouse I only have a small fridge to ferment in, I have to do this in two goes. The first cubes OG read 1052 which I thought no problems, first brew, maybe my efficiencies down. The next cube came in over with an OG of 1065 (this was the first cube to be filled). Odd.
I guess my questions are, Can a wort liquid settle out into layers of different strengths? Has this happend to anyone else?

Cheers,
Alex

 

[jakub76]

That seems like a huge difference, only thing I can think of is temperature affecting the read. Did you take both readings at the same temp? I would think something must have affected one or both of your readings - unless there was pile of sugar in one of the cubes

 

[megs80]

I know its weird, Both samples were taken when yeast was pitched at 19 degrees. Also I didnt use any DME or sugar that would explain the difference.

 

[Fourstar]

I know its weird, Both samples were taken when yeast was pitched at 19 degrees. Also I didnt use any DME or sugar that would explain the difference.

did you take the readings with a hydro or a refrac? sometimes i get funny readings with my refrac or my hydro so i cross reference them to see if they are same-same. Usually temperature is the issue or break material affecting the readings.

 

[megs80]

I only have a hydo. The sample had a bit of break material in them. I just let that settle before adding the hydro. If this happens again, I might need to invest in a refrac

 

[Maple]

is there a (remote) possibility that one has started to spontaneously ferment (the lower OG one)?

Also seems that stratification could be part to play, but that's a big difference. were both fermenters given a good mixing/airation before sample was taken, i mean like tipping the NC cube into the fermenter from a height? this would eliminate the stratification reasoning...

 

[Acasta]

Well considering SG is a reading a density, and liquid with more density will be heavier then liquid with less density, maybe the more dense wort started to separate when you were filling/resting.

 

[bcp]

Be interesting to mix up a sugar solution - or DME - and leave it sit for a while, skim off the top and measure gravity, then measure what's left separately. It would tell whether it stratifies. But not so interesting that i'm going to do it.

 

[megs80]

is there a (remote) possibility that one has started to spontaneously ferment (the lower OG one)?

Also seems that stratification could be part to play, but that's a big difference. were both fermenters given a good mixing/airation before sample was taken, i mean like tipping the NC cube into the fermenter from a height? this would eliminate the stratification reasoning...

I dont think there was enough time between cubing and fermenting for any bugs to change the gravity before I took a sample. Not that it can be completely ruled out, but the beer has finished pretty clean.
The sample with the lower OG was aerated better than the second batch. I dont know what difference that would have with the hydro. Next batch I put on ill take a reading before and after shaking the sample

 

[Vitalstatistix]

I dont think there was enough time between cubing and fermenting for any bugs to change the gravity before I took a sample. Not that it can be completely ruled out, but the beer has finished pretty clean.
The sample with the lower OG was aerated better than the second batch. I dont know what difference that would have with the hydro. Next batch I put on ill take a reading before and after shaking the sample

You could put the cube upside down to chill and then invert (the right way up" half an hour before sampling and puring into the fermenter maybe?