[Robert]

So I'm really thinking about a double-mash Doppelbock, which I think I should name "Duplicator!"  Here's my initial idea:

24# Munich 2
10 gallons Amber Full (Bru'n Water profile) liquor from RO

Mash 12# in 5 gal in my cooler lauter tun (single infusion)
Run off to kettle, hoping for 3.5-3.75 gal (clean LT)
Mash next 12# including mash off step
Trnasfer to LT and sparge as usual w/ other 5 gal
FWH only, noble type (amount TBD)
Boil down to 6.5 gal.and see what I get (based on Jim's results I'd espect ~1.090)
Pitch jumbo load of 34/70 and oxygenate twice

Brew in August (when I might usually have a brief break in the brew year), CP bottle from keg and savor at Christmas and for some time after! 

What I'm wondering is, if I just prepare all the liquor the same (as usual) might the buffer systems be set up so well in the first mash that I won't need any pH adjustment with salts directly in the 2nd mash? Thoughts?

[klickitat jim]

I have no clue. That's significantly different than what I did.

[Robert]

Different whole process, or just different water treatment? (Hey if everything's different, it's another learning opportunity.)

[klickitat jim]

You totally don't have to do it my way, I'm just saying that your plan differs from what I did enough that I don't know how to predict what will happen. I say go for it and see what happens.

[Robert]

You totally don't have to do it my way, I'm just saying that your plan differs from what I did enough that I don't know how to predict what will happen. I say go for it and see what happens.

I came up with this based on:

 1) the general idea being to split the grain bill in two and mash 2nd half in the 1st half's wort

 2) how to accomplish that with my equipment (I normally mash in my kettle, transfer to LT and sparge back to kettle, I just figured the LT is a good place for the first mash, since I dont want to mash off that one anyway)

I think the general plan (point 1) is probably as close to your brew last night as our different rigs will allow.

Anyway I was thinking, if the first wort pH is 5.4ish, and Bru'n Water says in plain RO the Munich would give a pH around 5.6, the 2nd mash should be in the ballpark, and when I sparge all the flavor salts will get in there.  If anybody thinks I'm way off, let me know.

Oh yeah I'll probably need a bit more sparge liquor, but details. Got half a year to figure it out.

[klickitat jim]

Regarding my double mash big stout... I oxygenated and pitched last night at 6pm. Second dose of O2 at 10pm. 3rd dose at 6am. Final dose at noon. It's gurgling away at near blow off pace already. And the pitch was one pack of 4 month old 1450 in a 1200ml active starter that I made that morning. Fantastic stuff!

[klickitat jim]

You totally don't have to do it my way, I'm just saying that your plan differs from what I did enough that I don't know how to predict what will happen. I say go for it and see what happens.

I came up with this based on:

 1) the general idea being to split the grain bill in two and mash 2nd half in the 1st half's wort

 2) how to accomplish that with my equipment (I normally mash in my kettle, transfer to LT and sparge back to kettle, I just figured the LT is a good place for the first mash, since I dont want to mash off that one anyway)

I think the general plan (point 1) is probably as close to your brew last night as our different rigs will allow.

Anyway I was thinking, if the first wort pH is 5.4ish, and Bru'n Water says in plain RO the Munich would give a pH around 5.6, the 2nd mash should be in the ballpark, and when I sparge all the flavor salts will get in there.  If anybody thinks I'm way off, let me know.

Oh yeah I'll probably need a bit more sparge liquor, but details. Got half a year to figure it out.

The only potential problem I see is the 2nd mashing, lots of grain in only 3.? Gallons of wort. It will be interesting see what happens.

[Robert]

I usually mash at 1.25 qt/lb, and in a pinch can go a little thicker.  Another reason to prepare more sparge water --  thin it out if I have to.  You only retained what, 1 gal? And I'll run the tun dry on the 1st mash, not stop when it gets cloudy --  all that cloudy stuff will filter out in the 2nd.

EDIT  in fact it occurs to me there's no reason to vorlauf the first mash.  Just open the valve wide and dump it!

[klickitat jim]

I had so much fun playing with this that I'm already planning on another Double Mash brew day in a few weeks.

I'm going to re-do this Stout, pretty much the same but changing the grain bill a bit.
20lbs Golden Promise
6lbs Dark Munich
2lbs Roast Barley
2lbs 425 Chocolate
And this time I'll split everything 50/50

The second brew is going to be I suppose a Barleywine, Big IPA, whatever
1.120 target OG
20lbs Golden Promise
10lbs Dark Munich
About 17srm
Double Mash split 50/50
55Ca 5Mg 25Na 55Cl 170 SO4 65HCO3

50g Chinook FWH
50g each of
Chinook
Cascade
Centennial at Wirlpool 170 for 20
I'll use 1450 again, see how it goes

[erockrph]

I think I have a post about my iterated mash brewday years back, I'll try to find it at some point and share it here. It was an all-Maris Otter, 1.142 OG barleywine that finished down at 1.024.

Jim, there is one possible missed opportunity I see here. One of the advantages of an iterated mash is the ability to use two different mash temps. In particular, this is the only way to start at a higher mash temp and drop down afterwards. By starting with an alpha-amylase rest in the 158-162F range, you are making the initial mash very digestable to beta-amylase in the second mash. By doing the second mash at a long, low rest (like 145-148F for 90-120 minutes) you end up with a highly attenuative wort and can brew a very big beer that doesn't end up too thick and chewy.

[klickitat jim]

I think I have a post about my iterated mash brewday years back, I'll try to find it at some point and share it here. It was an all-Maris Otter, 1.142 OG barleywine that finished down at 1.024.

Jim, there is one possible missed opportunity I see here. One of the advantages of an iterated mash is the ability to use two different mash temps. In particular, this is the only way to start at a higher mash temp and drop down afterwards. By starting with an alpha-amylase rest in the 158-162F range, you are making the initial mash very digestable to beta-amylase in the second mash. By doing the second mash at a long, low rest (like 145-148F for 90-120 minutes) you end up with a highly attenuative wort and can brew a very big beer that doesn't end up too thick and chewy.

That's really an interesting idea and I like it. So the enzymes of the second lower temp mash also go to work on the long chain left by the first mash? Hmmm.

My first batch, fermenting now, was mashed at 150/150 if I recall.


I'll try 160 for 45 and 148 for 90. At that volume i think I can hold that, might end up about 145 after 90.

Changed in my recipe, thanks Erock, that's a fantastic idea!

[erockrph]

That's really an interesting idea and I like it. So the enzymes of the second lower temp mash also go to work on the long chain left by the first mash? Hmmm.

Sort of, the first mash breaks the long chain starches into smaller-chain dextrins. So to visualize it - Beta amylase (low mash temps) is like Pac Man - it starts on one end of the string and bites off fermentable maltose sugars. This makes for high fermentability, but the caveat is that it can only work on the end of a chain so it takes a while to keep biting off small bits at a time. Alpha amylase (high mash temps) is like a samurai on meth - it randomly hacks the long chains into random pieces - dextrins primarily. That doesn't make for the most fermentable wort on its own. By letting the alpha amylase go to town first, it creates a lot more "ends" for the Beta to work on, making your low-temp mash more efficient.

[klickitat jim]

Excellent,  I'll try it for sure

[klickitat jim]

7 days in the fermentor and it's dropped from 1.110 to 1.030, still lots of yeast in suspension, still an occasional airlock bubble, and the samples tasted pretty darn good for being at the stage it is.

Looks to me like a vitality started might be a viable method for big beers.

69% ADF, 2.8°p per day is a bit on the fast side, but in the sample it wasn't as "hot" as I would expect. I'll check it in another week.

[Robert]

7 days in the fermentor and it's dropped from 1.110 to 1.030, still lots of yeast in suspension, still an occasional airlock bubble, and the samples tasted pretty darn good for being at the stage it is.

Looks to me like a vitality started might be a viable method for big beers.

And clearly forgetting your O2 wand was no problem!