Partial Part boiling?

[kiwirevo]

Firstly I can currently only do approximately 2 Gallon mash/boils BIAB so for my previous brews that have required more grain than that setup handles I've just split the grain and done one after the other but I've always done the same hopping procedure or been using a prehopped malt extract so haven't had to worry much about it.
I've recently been given about 30 lbs of LME for free so I've been trying to build a few recipes to try and use it, my only problem is that I'll need to add all the hops to it and I'm not sure if doing only 2 Gallon mash & boil with some grain will be enough to absorb all the bitterness etc required for a 5 gallon wort.
So my first question is how much of the hop bitterness would be picked up in a 2 gallon boil and would it be enough to create a 5 gallon wort?

Secondly I was thinking about doing an Imperial IPA with 5 hops 5 ways. So I was think 2lbs of pale 2 row then first wort hop with 1.5 oz of Motueka, then add 1.5oz of Super Alpha and boil for 60 mins. Pour that into my fermenter and start cooling whilst I do 2 more boils both with 6 lb of LME. I'd boil one for 15 mins with 1.5 oz of Cascade and the other would be just bring to boil add 1.5 oz of Sauvin and take it off the heat. I'd combine all 3 worts into the one fermenter. (the 5th hop would be dry hopping with 1.5oz of Hallertau)
Would this work? or would I just lose to much out of each hop addition due to not enough liquid?

Cheers for your help

 

[kiwirevo]

Oh well, I bought all the hops etc (and another fermenter) so I'm going to try it anyway

 

[ChessRockwell]

So my first question is how much of the hop bitterness would be picked up in a 2 gallon boil and would it be enough to create a 5 gallon wort?

Yes, you'll have to adjust amounts and use a fair amount more hops than if you were doing a full boil though. You might want to check out some brewing software, if you don't have any you can use hopville.com's brew calculus.

Your second plan sounds confusing and difficult to calculate bitterness, although I guess it could work. Why not just get another boil pot (pretty cheap at wal-mart) and do a split boil (2 gal in each pot). Just split all the ingredients, including hop additions, evenly between the two, then combine in the end after cooled. Either way you should definitely check out some brewing software!

 

[kiwirevo]

I use brewers friend but it I wasn't sure if I was using it correctly, after reading your post I went and had a play with batch and boil sizes and it seems I was using it wrong.

If I do three recipes on brewers friend could I just add them together?
with batch sizes of 5 gallons but boil sizes of 2ish?

 

[ChessRockwell]

Eesh, I'm not sure, never used that particular software. What would you do, average the IBU's/gravities/etc between the 3? I mean, you can't really just add the numbers up, there's more to it than that...

Seems easier to me to just do ONE recipe and split the boil between two pots if you have to.

 

[ludomonster]

You could brew threw batches with recipes made for your capacity. That is, brew 3 ~2-gallon IIPA's at your expected starting gravity and IBU level. Blend them together and you will have ~6 gallons of wort at the same OG and IBU. This is a common practice in commercial breweries where they blend batches of beer for consistency. It isn't practiced very much in homebrewing.

 

[kiwirevo]

I brewed it last week before checking back here and I ended up doing it in 3 different batches, time really was the limiting factor to doing the 3 of the same batches as 3 90 minute boils on a weeknight would have had me up all night. I calculated each boil seperately with the batch size of 5 Gallons and boils of 2 and I think adding it together is close. If you think about it the bitterness abv etc are all calculated for the effect they have on the total 5 gallons and by adding them together they will come close what the total would be. I'm not too concerned if it's wrong, I'll still drink it, and considering I made the recipe up it's not like I was trying to repeat something else I've tried.
I did swap the Super Alpha for Centennial.

I'll let you know how it turns out, it's smelling supremely hoppy in the fermenter.