Author Topic: Split batches with different OG's & IBU's  (Read 531 times)

Offline erockrph

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Split batches with different OG's & IBU's
« on: July 30, 2013, 06:25:12 PM »
Due to a serious lack of time I want to combine two similar brews into one brewday, then split them off partway into primary. I thought I'd bounce my basic plan off of the forum in case I'm overlooking something or if someone has a better idea.

I want to end up with 3 gallons of 1.040/28 IBU saison and 3 gallons of 1.048/8 IBU lambic. I can produce 4 gallons of wort max in a batch. So here's what I was thinking:

Main batch - 4 gallons of 1.040/12 IBU wort. Pitch 3711 and ferment in the mid 60's for 3 days.

After 3 days i will rack 2 gallons into a separate fermenter and add 1 gallon of unhopped wort to bring the 3 gallons up to 1.048 (and thus dilute the IBU's from 12 to 8]. By my calculation this is equal to about 1.5 lbs of light DME. At this point I pitch my bugs and strap on my Brew Belt to kick the lacto into gear. This way I also get some flavor and mouthfeel contributions from the 3711, but add some food back for the lacto.

The remaining 2 gallons get a gallon of 1.040 wort with enough IBU's to bring the 3 gallons up to 28 IBU's (60 IBU's by my calculation), plus my flameout hops. Once it's finished I will process as usual (one gallon will be going on some red and pink currants, and some on hibiscus as well).

So, does this sound reasonable? Am I missing anything obvious?
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer

Offline Steve in TX

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Re: Split batches with different OG's & IBU's
« Reply #1 on: July 30, 2013, 09:42:09 PM »
Honestly, the whole process and math sounds like a PIA to me. Why not brew two 3 gallon batches?

Instead of two normal brew days, you are looking at 1 normal brew day and two half-ish brew days worth of time and effort.

I do feel your woes. My kettle is only big enough to get me 9.5 gallons at the end of boil. When I want 10 gallons I end up adding 1.5-2 gallons of water that I boiled for 10 minutes while mashing. I have played with adding the extra water to the kettle at flameout as well as adding it all to one fermenter as a faux partigyle. Faux partigyle works well with some styles, not so well with others.

Online kramerog

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Re: Split batches with different OG's & IBU's
« Reply #2 on: July 30, 2013, 10:47:10 PM »

After 3 days i will rack 2 gallons into a separate fermenter and add 1 gallon of unhopped wort to bring the 3 gallons up to 1.048 (and thus dilute the IBU's from 12 to 8]. By my calculation this is equal to about 1.5 lbs of light DME. At this point I pitch my bugs and strap on my Brew Belt to kick the lacto into gear. This way I also get some flavor and mouthfeel contributions from the 3711, but add some food back for the lacto.
...
So, does this sound reasonable? Am I missing anything obvious?

I don't think your plan for souring will work.  Not sure what specific lacto strain you'll be using, but I doubt you'll get much sourness from the lacto as the yeast will eat up the fermentables in your unhopped wort.   Also heating up already fermented wort sounds like a bad idea.  It would make more sense to sour the unhopped wort and then add it to the 2 gallons of fermented wort.
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Offline dmtaylor

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Re: Split batches with different OG's & IBU's
« Reply #3 on: July 31, 2013, 04:30:56 AM »
erockrph, your plan probably sounds crazy to most people, but I do think it will work pretty well.  I have done some unusual things with split batches like this before, especially when it comes to partigyle, when I'm trying to jack up the second partigyle beer to something rich and flavorful (as opposed to sort of dull and lifeless, which is characteristic of the second runnings of any mash).  So, I say, go for it.  Looks like after those first 3 days, the second two mini extract batches will be a cinch to boil up and chill and get into your already fermenting beer.  Overall it should save you a couple hours versus brewing two 3-gallon batches.
Dave

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Offline erockrph

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Re: Split batches with different OG's & IBU's
« Reply #4 on: July 31, 2013, 05:13:54 AM »

After 3 days i will rack 2 gallons into a separate fermenter and add 1 gallon of unhopped wort to bring the 3 gallons up to 1.048 (and thus dilute the IBU's from 12 to 8]. By my calculation this is equal to about 1.5 lbs of light DME. At this point I pitch my bugs and strap on my Brew Belt to kick the lacto into gear. This way I also get some flavor and mouthfeel contributions from the 3711, but add some food back for the lacto.
...
So, does this sound reasonable? Am I missing anything obvious?

I don't think your plan for souring will work.  Not sure what specific lacto strain you'll be using, but I doubt you'll get much sourness from the lacto as the yeast will eat up the fermentables in your unhopped wort.   Also heating up already fermented wort sounds like a bad idea.  It would make more sense to sour the unhopped wort and then add it to the 2 gallons of fermented wort.

The sour beer is a lambic, not a Berliner Weisse, so eventually pedio will take over the rest of the souring. I'm pitching a mixed culture I've built up from some lambic and Flanders dregs, so I'm not really counting on the lacto for all the sourness. And I'm not talking about heating the fermented wort super hot. With my Brew Belt I doubt I can get much higher than 80F, which is where I'd normally be ramping 3711 to anyways. I just want to make sure the lacto gets as much food as it can before the 3711 finishes up.
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer