Split batch weird OG.... can someone explain?

[dannymars]

so, I did a split batch this weekend....

69 litres pre boil.... (don't know pre boil SG)

ran 23 litres off for kettle souring....

boiled 47 litres for 1 hour, to reach 37 litres and a OG of 1.046

soured 23 litres with two bags of grain @ 36C for 48 hours...

boiled 23 litres for 30mins ... fermenter volume (approx 18 litres)... now the weird bit.... OG 1.052

????????

am I missing something here?

 

[Ducatiboy stu]

The grains may of added sugars

 

[Danscraftbeer]

I'm not sure what you're doing there but the whole conversion to sugars in the mash seems to happen after the mash as well? I cant verify that with any expertise but I had to leave a pre boil on low heat for maybe 12 hours before doing the main boil. The OG was surprisingly overshot.
You added grains so there it is. Interesting technique.

Edit: some more details would be good. Two bags of grains is how much? :unsure: Was it milled grain?

 

[Rocker1986]

The grains maybe added starches? Would that push the SG up? Can't imagine they'd convert to sugars at 36C. :unsure:

 

[Danscraftbeer]

Our body converts sugars around those temps. With enzymes and stuff. Its a sour mash.

 

[MHB]

All the enzymes in barley work at ambient, they wouldn't be much use to a growing barley plant otherwise, there are also a bunch of enzymes that are denatured at temperatures well under those we use.
It would take about 2 weeks to completely mash a grain bill at 20oC, naturally it would be a bit infected. Enzymes just work faster and faster (until the wheels fall off) as it gets warmer. If you ramped the temperature up from 20-80oC at about 1/2oC/minute (over two hours) you would go through the peak range of each enzyme slowly enough to achiever all they are going to do, fully mashing the grist.

Nothing new or surprising here - except the OP's boil off rate, it looks like its over 20%/hour on the 47L batch, it would be that or higher on a smaller batch.
I would think that much heat is doing some damage to the wort (thermal exposure is a measurable quantity), not only does it damage the beer it is a pretty big waste of energy (money) - I would be looking to wind the fire down a couple of notches.
The other point is that keeping some basic records really does help, especially when you have a question about what is going on, helps you to diagnose any problems, see where you can make improvements and when you make a ripper of a beer - make it again!
Mark

 

[dannymars]

All the enzymes in barley work at ambient, they wouldn't be much use to a growing barley plant otherwise, there are also a bunch of enzymes that are denatured at temperatures well under those we use.
It would take about 2 weeks to completely mash a grain bill at 20oC, naturally it would be a bit infected. Enzymes just work faster and faster (until the wheels fall off) as it gets warmer. If you ramped the temperature up from 20-80oC at about 1/2oC/minute (over two hours) you would go through the peak range of each enzyme slowly enough to achiever all they are going to do, fully mashing the grist.

Nothing new or surprising here - except the OP's boil off rate, it looks like its over 20%/hour on the 47L batch, it would be that or higher on a smaller batch.
I would think that much heat is doing some damage to the wort (thermal exposure is a measurable quantity), not only does it damage the beer it is a pretty big waste of energy (money) - I would be looking to wind the fire down a couple of notches.
The other point is that keeping some basic records really does help, especially when you have a question about what is going on, helps you to diagnose any problems, see where you can make improvements and when you make a ripper of a beer - make it again!
Mark

Thanks for this, and everyone else for their comments.

That's 37 litres into the fermenter... so that's including 2-3 litres of trub loss, pluss thermal shrinkage.

I usually make a starter for the lacto... so 1/2 cup of unmilled grain into 2litres of wort for 48 hours then pitch the starter (sans grain)... I ran out of time this week, and put in a couple of hop socks full of grain (approx 400gram all up) into the full 23 litres... I think that this has made the OG difference... Something I didn't even consider.

I've done kettle souring many times, with great results. This one turned out weird tbh... wort has a strange pinkish-brown hue, tastes a little woody, not unpleasant, didn't get as tart as usual either... I usually get down around 3.4 PH and this one just touched on 3.7....

Guess I'll see how it goes...

 

[dannymars]

I'm not sure what you're doing there but the whole conversion to sugars in the mash seems to happen after the mash as well? I cant verify that with any expertise but I had to leave a pre boil on low heat for maybe 12 hours before doing the main boil. The OG was surprisingly overshot.
You added grains so there it is. Interesting technique.

Edit: some more details would be good. Two bags of grains is how much? :unsure: Was it milled grain?

Something to note, that I also mashed out @ 76C for 10mins... but yes, the enzymes may have still been active I guess.

 

[MHB]

Sounds like this one has picked up an atypical bug - that's where everything I think I know about brewing goes out the window.
There are bugs that can do almost anything, that's part of why as much as I enjoy sour beer I don't really want them in my brewery, bit like herpes once you have it you probably have it for life. Bugs just keep cropping up an inconvenient times.

MArk

 

[Rocker1986]

All the enzymes in barley work at ambient, they wouldn't be much use to a growing barley plant otherwise, there are also a bunch of enzymes that are denatured at temperatures well under those we use.
It would take about 2 weeks to completely mash a grain bill at 20oC, naturally it would be a bit infected. Enzymes just work faster and faster (until the wheels fall off) as it gets warmer. If you r.... <snip>

Well, you learn something new every day. Although that first sentence makes perfect sense now it's been said. Cheers mate.

 

[Jack of all biers]

Something to note, that I also mashed out @ 76C for 10mins... but yes, the enzymes may have still been active I guess.

Sounds like this one has picked up an atypical bug - that's where everything I think I know about brewing goes out the window.
There are bugs that can do almost anything, that's part of why as much as I enjoy sour beer I don't really want them in my brewery, bit like herpes once you have it you probably have it for life. Bugs just keep cropping up an inconvenient times.

MArk

Yes, the enzymes in the original mash were likely mostly denatured, but don't forget that you added 'two bags of grains' to the 37L and left them for 48 hours at 39C. This is more than enough time for the uncrushed grains to absorb water/wort, swell till some of them split probably (have you ever left grains of dried beans in water for 48hr?), for the enzymes present in the fresh 'two bags' to start their job and break down the sugars in the whole grains, which in part are released into their environment.
Now the question is, how big were those two bags of grains?

 

[dannymars]

Roughly 200grams each

 

[Jack of all biers]

:lol: I just realised we may have all been off track on this one....

so, I did a split batch this weekend....

69 litres pre boil.... (don't know pre boil SG)

ran 23 litres off for kettle souring....

boiled 47 litres for 1 hour, to reach 37 litres and a OG of 1.046

soured 23 litres with two bags of grain @ 36C for 48 hours...

boiled 23 litres for 30mins ... fermenter volume (approx 18 litres)... now the weird bit.... OG 1.052

????????

am I missing something here?

We were all thinking of the grains you added or the enzymes having some effect, but it could have been something simple that has been overlooked. You will have the answers though.

Did you take the 23 Litres for souring from the first runnings or sparge all 67 Litres and then run off 23 Litres from that? If it was the first runnings then that answers the mysterious rise in your post boil for the souring portion. Also were all gravity readings taken at the calibrated temp of your hydrometer? (usually 20C)

If your answers to the above are; yes correct hydrometer temps for reading; and all the wort was first mixed then the 23 Litres were run off... Then the 400 gm Pilsner malt could, technically, convert to 1005-ish in a 23 Litre batch (based on Vicbrew 2002 almanac's specific gravity for 1 kg Pilsner malt in 25 L being SG of 1011 at 65% efficiency).

 

[dannymars]

Did you take the 23 Litres for souring from the first runnings or sparge all 67 Litres and then run off 23 Litres from that? If it was the first runnings then that answers the mysterious rise in your post boil for the souring portion. Also were all gravity readings taken at the calibrated temp of your hydrometer? (usually 20C)

Yes, the wort was thoroughly mixed, and the readings were taken at 20C