Split Mash RIS Procedure

[bonecitybrewco]

Just wondering how everyone is doing split mashes. I am planning on doing the following -

Heat strike water to mash in temp
Mash with ~1/2 of grain bill while maintaining target mash pH via Bru'n water
Remove bag/squeeze, place into separate vessel and add sparge water/stir let sit for 15 mins.
Dump bag and add 2nd half of grains
Reheat 2nd runnings up to mash in temp and dough in, mash as scheduled
Remove/squeeze bag, place into 2nd vessel with 2nd runnings, stir and leave for 15 mins, stir again and dump grains.
Add "2nd runnings" to first runnings and proceed as per normal

Does this sound correct or am I missing something?

Target OG is 1.104 and I know getting that with straight mash/double batch sparge may be difficult even with accounted for efficiency loss. I am normally at 83% BH efficiency but haven't done this big of a beer and so calculated at 70%. Wondering if I should calculate lower or the same for this batch based on this procedure.

I do have a large enough vessel to do a full volume mash in the bag without a sparge but I imagine it would be horrible efficiency...

Any ideas/thoughts?

Thanks in advance!

 

[nolabrew85]

I heard Jamil talking about doing something like this without rinse of the grains in the other vessel. Supposedly it works. Let us know how it works for you. I plan to try it soon

 

[Brewsader1]

I recently did this method and although it was a long day, it worked out well. Ended up about 7-8 % below my normal efficiency, but got a little antsy on the second mash and rushed it. I did all the water profile adjustments for the first mash and there wasn't much change in pH from the second mash.

I think your plan makes sense, but if you have the capacity, the "polygyle" idea is that you don't have to do a second runnings. Just use all the water for your first mash, get your runnings out, heat the wort up, then do the second mash. Good luck!

 

[bonecitybrewco]

I recently did this method and although it was a long day, it worked out well. Ended up about 7-8 % below my normal efficiency, but got a little antsy on the second mash and rushed it. I did all the water profile adjustments for the first mash and there wasn't much change in pH from the second mash.

I think your plan makes sense, but if you have the capacity, the "polygyle" idea is that you don't have to do a second runnings. Just use all the water for your first mash, get your runnings out, heat the wort up, then do the second mash. Good luck!

Thank you so so much! Were your water calculations based on half the grain or the full grain bill?

 

[Brewsader1]

Thank you so so much! Were your water calculations based on half the grain or the full grain bill?

I use the Bru'n water spreadsheet and I put everything as normal (including the full grain bill) except I assumed all my water was going in the mash. All salt additions went in the mash. My mash tun couldn't actually take 3 gallons the first mash and I think 1 for the second, but once I started running the wort out, I just topped off with the excess water. That may also be a reason for a slightly lower efficiency. But if you can get all the water in, that is the way to go.
If you are doing a big dark beer and adding all the water adjustments to the first mash weirds you out, you could front load all your darker grain (assuming you have enough base malt in this for full conversion) so that you maximize your grain-based pH drop with your buffer from the additions. I split it with maybe a bit more of the darker grain in the first mash and was a bit surprised at the pH stability of the second mash compared to the first.

 

[bonecitybrewco]

I use the Bru'n water spreadsheet and I put everything as normal (including the full grain bill) except I assumed all my water was going in the mash. All salt additions went in the mash. My mash tun couldn't actually take 3 gallons the first mash and I think 1 for the second, but once I started running the wort out, I just topped off with the excess water. That may also be a reason for a slightly lower efficiency. But if you can get all the water in, that is the way to go.
If you are doing a big dark beer and adding all the water adjustments to the first mash weirds you out, you could front load all your darker grain (assuming you have enough base malt in this for full conversion) so that you maximize your grain-based pH drop with your buffer from the additions. I split it with maybe a bit more of the darker grain in the first mash and was a bit surprised at the pH stability of the second mash compared to the first.

Thank you again so much for all of this information. My last question I think was what your temp loss was relative to predicted? Beer smith calculates a 12F drop but it's calculating with all the grain. I assume that the drop will be less with less grain but I also assume it's not linear and so wouldn't be half of the predicted either. Thoughts?

 

[Brewsader1]

Thank you again so much for all of this information. My last question I think was what your temp loss was relative to predicted? Beer smith calculates a 12F drop but it's calculating with all the grain. I assume that the drop will be less with less grain but I also assume it's not linear and so wouldn't be half of the predicted either. Thoughts?

My total grist was 36 lbs, and I was using 16 gallons total water to end up with 8.5 gallons in the end. With about half the grain and I believe 13 gallons of strike water I ended up with a 7 deg F loss (162 to 155). I intentionally overshot the first mash because it would be easier to cool with room temp sparge water. The second mash with similar quantities had an 8 deg F loss (158 to 150). I think the temp loss be relatively linear based on water/grist ratio. My mashes ended up about 2.9 qt/lb.

I hope that helps, and ask away any other questions! And be sure to post back how your brew day goes!

 

[bonecitybrewco]

My total grist was 36 lbs, and I was using 16 gallons total water to end up with 8.5 gallons in the end. With about half the grain and I believe 13 gallons of strike water I ended up with a 7 deg F loss (162 to 155). I intentionally overshot the first mash because it would be easier to cool with room temp sparge water. The second mash with similar quantities had an 8 deg F loss (158 to 150). I think the temp loss be relatively linear based on water/grist ratio. My mashes ended up about 2.9 qt/lb.

I hope that helps, and ask away any other questions! And be sure to post back how your brew day goes!

FORGOT TO UPDATE! Cannot believe I forgot! Brew day went exceptionally well, although long. For me, a normal brew day is about 5 hours. This was closer to 8. That being said, all went well and I managed to nail 70% efficiency on the head. This is still not quite high enough for me to be entirely satisfied with, though, I am not sure I can realistically expect more on the homebrew scale. I did end up sparging with approx 2 gallons of water, following the process I listed. Boil was a full 2 hours. Somehow, a screwdriver got dropped in the boiling wort while attaching hose to the chiller but managed to retrieve it quickly enough. It has now been dubbed the Screwdriver Imperial Stout. Not bad for just going with it.

Thanks for the help from everyone in this thread.