Huge Stout: Split Mash or Sparge?

[brewman !]

You should sparge the 2nd mash with wort instead of water. Increase the sparge volume of the first mash and set some wort aside to sparge the 2nd mash with.

The only thing about thin mashes is the pH might be high.

You could mash these mashes in your grainfather too.

 

[deadwolfbones]

You should sparge the 2nd mash with wort instead of water. Increase the sparge volume of the first mash and set some wort aside to sparge the 2nd mash with.

The only thing about thin mashes is the pH might be high.

You could mash these mashes in your grainfather too.

Yeah, that was my plan. And I can adjust pH.

What is the advantage to sparging with wort vs water?

 

[brewman !]

You rinse the first mash with more water which extracts more sugars from the wort.

 

[deadwolfbones]

But wouldn't you extract less sugar from the second mash by sparging with wort instead of water?

 

[deadwolfbones]

So, basically, you're suggesting I mash with, say, 5 gallons the first time and sparge with 4 gallons, ending up with 8.25 gallons after grain absorption. Then reserve ~3-4 gallons of the first mash wort, mash the second mash in the 4.25 to 5.25 gallons of remaining wort, and sparge the second mash with the 3-4 gallons that I reserved?

Second question: do I squeeze the bag before or after the sparges?

 

[brewman !]

But wouldn't you extract less sugar from the second mash by sparging with wort instead of water?

I had the same thought when I answered your question, but I think the answer is no.

If you do this, please keep careful track of gravities and volumes and report back what happens. Also please taste the spent grains to get a feel for how much sugar is left in them post sparging.

 

[brewman !]

So, basically, you're suggesting I mash with, say, 5 gallons the first time and sparge with 4 gallons, ending up with 8.25 gallons after grain absorption. Then reserve ~3-4 gallons of the first mash wort, mash the second mash in the 4.25 to 5.25 gallons of remaining wort, and sparge the second mash with the 3-4 gallons that I reserved?

I don't know the volumes of your system, but yes, that is the process.

Second question: do I squeeze the bag before or after the sparges?

I'm not a BIAB guy, so I don't really know, but I think you do it after.

 

[doug293cz]

So, basically, you're suggesting I mash with, say, 5 gallons the first time and sparge with 4 gallons, ending up with 8.25 gallons after grain absorption. Then reserve ~3-4 gallons of the first mash wort, mash the second mash in the 4.25 to 5.25 gallons of remaining wort, and sparge the second mash with the 3-4 gallons that I reserved?

Second question: do I squeeze the bag before or after the sparges?

You're starting to understand why I asked the question about what is the optimal sparge protocol for reiterated mashing. It's not immediately obvious what the best way to proceed is (best meaning leading to the highest lauter efficiency.) I don't know the answer yet, but I know how to go about finding the answer. I can modify my simulator to deal with the different sparging possibilities, and then run a bunch of scenarios (which is much easier than running a couple dozen brew trials.) How much of a hurry are you in to do this brew?

I can tell you that best results with squeezing are to squeeze both before and after sparging. The less sugar left in the grain prior to sparging the more total sugar you recover from the mash. For single step mash with batch sparge, optimal lauter efficiency is obtained when the initial mash runnings volume and the sparge runnings volume are approximately equal.

Brew on

 

[deadwolfbones]

I can tell you that best results with squeezing are to squeeze both before and after sparging. The less sugar left in the grain prior to sparging the more total sugar you recover from the mash. For single step mash with batch sparge, optimal lauter efficiency is obtained when the initial mash runnings volume and the sparge runnings volume are approximately equal.

Thanks for that info, Doug. I kind of need to brew the beer ASAP since I don't want the barrel to dry out, so I'll be doing it this Saturday. I think I'm going to go with the polygyle, and I'll let you guys know how it goes.

 

[deadwolfbones]

Well, halfway through the polygyle right now.

SG was 1.068 post-squeeze, "sparge" was 1.015. Combined around 1.042. Mashing the second half in half of the combined runnings now. So far, so good!

As you'd expect, the second mash is waaaaay thicker despite using the same volume of liquid and the same amount of grain.

SG at 1hr into the second mash is 1.094.

SG after squeezing second mash is 1.121.

Pre-boil SG is 1.089. (Or 1.090 according to the hydrometer.)
Still getting a 2hr boil, 1.5 lbs of maltodextrin, and 1 lb of cane sugar.

 

[deadwolfbones]

Aaaand we have a 1.121 OG and exactly 6 gallons. Success!!

Thanks for all the help, @doug293cz and @brewman !

 

[wilserbrewer]

Nice work, interesting!
Thanks for posting.

How many pounds of grain?

 

[deadwolfbones]

22.9 @wilserbrewer

(Total, split into two mashes)

 

[deadwolfbones]

I wrote up the brew day here, if anyone is curious: https://brew4fun.wordpress.com/2019/01/13/polygyle-party/

 

[brewman !]

Good work ! Nice write up. Did you run any efficiency calcs ? I guess we could do it from the numbers in your blog. Did 1090 include any adjuncts or was that due to the grain alone ?

21.9 pounds of fermentables x 37 = 810 possible gravity points.
7 gallons x 1.090 = 630 gravity points
630/810 = 77.7% efficiency ???? Darn good for a big beer, if the calcs are right !

How sweet were the spent grains from the 2nd mash after the sparge ?

Here is another reiterative brewing post:
https://www.homebrewtalk.com/forum/threads/my-reiterated-mash-experience.659513/

 

[deadwolfbones]

Yeah, I got 78% pre-boil efficiency when I calculated it. (Though I just did it again using the Brewers Friend calculator and got 75.77%—slightly lower PPG based on grainbill than you were anticipating there.) The adjuncts were added during the boil. Very pleased with that result!

BH efficiency was 71%, including the adjuncts.

Sorry, didn't taste the grains. Was pretty tired at that point, and fighting a nasty head cold, too.

 

[deadwolfbones]

Update: Down to about 1.059 after ~4 days and still bubbling steadily. I'm gradually raising the temp from 64-65F, where it's been so far, up to 68-70F to finish.

 

[deadwolfbones]

And down to 1.047 today. Still bubbling, still a krausen, still plenty of yeast in suspension. Temp up to 67F.

 

[Mer-man]

I did a polygyle. Worked well.

 

[brewman !]

That is astounding efficiency given the sparge method and how large the grain bill was. I'm going to brew an imperial stout in a couple weeks. I'll do a reiterative mash, of course.

 

[deadwolfbones]

Down to 1.040 and still truckin'. Temp up to 70F. Sample was delicious.

 

[schmurf]

Apologies for OT but some question regarding reiterated mash like @deadwolfbones did. What about water treatment for such a method? Wouldn't pH be way off when doing the second mash?

 

[deadwolfbones]

Apologies for OT but some question regarding reiterated mash like @deadwolfbones did. What about water treatment for such a method? Wouldn't pH be way off when doing the second mash?

According to Chris Colby's article, if you do the same calcium additions in the second mash that you did in the first mash you'll end up in the right ballpark. I did that and got good conversion/attenuation.

 

[deadwolfbones]

Stout went into the barrel last night. Despite having more than 6 gallons going into the fermenter, I only managed to fill the barrel like 90% of the way before I ran into a soup of yeast and trub. Oh well, talked to a pro brewer friend and he said to just let it ride.

 

[wilserbrewer]

Note to self...perhaps cold crash next time.

Can make a big difference in volume losses...

 

[deadwolfbones]

Cold crashed for 72 hours @ 35F.

 

[wilserbrewer]

Longer and colder lol

73 hours is not that long as it takes 24-36 to lower the temp that far...:unless you mean 72 hours started at 35 degrees.

I’m talking a week, preferably two.

What’s the hurry, thought this was an aging project?

Nice work regardless

 

[deadwolfbones]

Yeah, I started the cold crash proper at 44F. Next time I'll do colder and longer, though.

 

[Amesanite]

What was your FG? Apologies if i missed it.

 

[EnglishAndy]

Iy

What was your FG? Apologies if i missed it.

It's in his blog: 1.037

 

[Bill Hopper]

Option 4: reiteritative or polygyle mashing. Google is your friend.

I just googled this and it took me to this very post : )

 

[Hwk-I-St8]

If I'm brewing a big stout, that means a longer boil and higher pre-boil volume. Doing a mash/sparge with that higher volume yields almost the exact same efficiency as a regular beer which is a double bonus: no loss in efficiency and no need to change my settings in Brewer's Friend to account for a change in efficiency.

This is a no-brainer for me and my MIAB setup.

 

[doug293cz]

If I'm brewing a big stout, that means a longer boil and higher pre-boil volume. Doing a mash/sparge with that higher volume yields almost the exact same efficiency as a regular beer which is a double bonus: no loss in efficiency and no need to change my settings in Brewer's Friend to account for a change in efficiency.

This is a no-brainer for me and my MIAB setup.

I think you are being overly optimistic about getting "almost the exact same efficiency as a regular beer" with a slight (1 - 2 gal) increase in pre-boil volume. If you double your grain bill, you have to double your pre-boil volume to get the same efficiency (if the rest of you lauter process remains the same.) You can run some scenarios yourself using the spread sheet here, to get a feel for how things work.

Brew on

 

[Hwk-I-St8]

I think you are being overly optimistic about getting "almost the exact same efficiency as a regular beer" with a slight (1 - 2 gal) increase in pre-boil volume. If you double your grain bill, you have to double your pre-boil volume to get the same efficiency (if the rest of you lauter process remains the same.) You can run some scenarios yourself using the spread sheet here, to get a feel for how things work.

Brew on

You'd think so, but I got about 72% brewhouse normally and got 71% brewhouse with a 1.128OG beer.

 

[doug293cz]

You'd think so, but I got about 72% brewhouse normally and got 71% brewhouse with a 1.128OG beer.

I would bet that if we could look at all the detailed information for the two cases, we could identify what is different in the two processes, in addition to the increase in grain bill.

Brew on