4 SMaSHes from one mash

[lurker18]

I am planning to do 4 2.5 gallon smashes from one mash and would like some advice. I have a chest cooler all grain setup, do batch spares. I will be using Maris Otter for the grain. I am planning to mash this a little warm, about 156 and spare with 170-175 rinse, then split it into 4 boils for the hops. Can someone guess at an appropriate amount of MO to use in this, probably going to need close to 12 to 15 gallons pre boil to split into 4 boils.
Going to be using Apollo (17.5%AA), Delta(4.5% AA), Calypso (15.1%), and Citra (14.5% AA) as the hops.

 

[buzzerj]

Ok an effective evaporation rate for a boil is 12-15%. Let's assume you boil vigorously and expect to lose 15% of the initial boil volume. So for exactly 10 gallons you need to start with 11.5 gallons. So for 4 theoretical 2.5 gallon batches, you will need to collect 11.5 gallons of sweet wort for the four separate boils.

You are mashing fairly high temperature so you will be getting a malty result. The question is how big of a beer do you want to result? Let's for example say you with a 5%ABV malty English pale ale. If so, you will need 21.25 lbs. of Maris Otter assuming 70% mash efficiency to get a 1.057 O.G. for 10 gallons post boil. If you are mashing 21.25 lbs. of grain at 1 lb. grain to 1.25 quarts of water you will mash with 26.5 quarts (6.625 gallons) of water with a strike temperature of 171 degrees F. I'd mash that for 60 minutes at that high of a temperature. Mash out at 168 degrees for 10 minutes by adding 8.4 quarts (2.1 gallons) of boiling water.

You need to sparge after lautering out by added 11.1 quarts of 170 degree water plus that amount of water expected to be soaked up by the grain and remain in the mash tun. That amount is the weight of the grain 21.25 lbs. divided by 8.3 lbs. in a gallon of water or 2.56 gallons. So you expect 2.56 gallons (10.25 quarts) will be retained in the grain mass in the mash tun. So you will need to sparge with 11.1 + 10.25 quarts or 21.35 quarts (5.35 gallons) of 170 degree water. That should get you a volume of 10 gallons after a vigorous boil to split among four fermenters at 2.5 gallons apiece. What's hard about that? Rock and roll baby!

 

[lurker18]

Thank you for all of that. I followed as close as I could for this and ended up with 3 beers, due to my lack of planning and limited kettle space. I Ended up with 2, 2.5 gallon SMaSHes (Calypso and Citra) and one 4 gallon brew from the leftovers (Delta hops for the aroma and finishing, Apollo for the 60 min boil). All three of the beer came in between 1.056 and 1.058 post boil, and are bubbling away right now. This is my first ever attempt at anything bigger than a 5 gallon beer, and if I was to do it again, a bigger boil pot is required. My old 5 gallon pots were closer to 6.5-7, so I could squeeze a 5 gallon beer into them, my new pot is 10 gallons exactly, right to the rim, couldn't get the last gallon and a half anywhere.