"Partigyle" Gravity Expectations

It's hard to give you an approximation due to the many, many variables. However, are you expecting something like 80% efficiency...because that's what a cursory look at the numbers would indicate.

If you were to get 80% efficiency...and depending on how well your sparge goes...I don't see how you'll be able to make much of a beer with the second sparge.

 

Yea I wouldn't partigyle if your first beer is gonna be that low. Last may I did a partigyle batch with a friend. We did a 120 minute boil on the first beer (1.100OG). 2nd runnings beer ended up at 1.047.

If you wanna partigyle this batch them cap the mash with more grains to avoid making a super low gravity tannin bomb.

After writing that I see your okay with a low volume on your second beer. Youl be pretty lucky to get a preboil OG greater than 1.030 on 2 gallons of "extra" wort. I often will run my mash tun dry after my last (batch) sparge and the gravity is usually around 1.030 but I never get a full gallon.

 

Your OG and batch size are to low for a decent second runnings beer, but if you put 1-1.5 gallons in there you can get some free starter wort. That is what I do.

If you want to parti then figure it out for a 10 gallon batch. Here is a handy online calc that works for the half and half split. I have not used it for the one third two thirds split.

 

Kai (Braukaiser) has a spreadsheet for this.
http://braukaiser.com/wiki/index.php?title=Batch_Sparge_and_Party_Gyle_Simulator

Spreadsheet here
http://braukaiser.com/download/batch_sparge_simulator.xls

If you have your numbers dialled in, it's pretty accurate. YMMV

 

My efficiency doesn't go up that much when I parti-gyle. It just saves me time on brewing 2 beers.
http://morebeer.com/brewingtechniques/library/backissues/issue2.2/moshertable.html

 

What you'll most likely get is a lot of tannins and a grainy, bland beer.

Personal advice, as most have suggested above, brew a bigger beer for your first batch to actually have sugar left to extract from the mash after sparging. If thats not in the cards, cap the mash with some extra basemalt and character malts after sparging, and do a second mash or actually blend the two gyles to make something that resembles beer in the second batch. Either way, do yourself a favor and make sure you have some extract on hand to bolster the gravity of the second beer.

 

Quick rule of thumb that I pulled from Mosher and company:

The first half of your runnings will have 2/3rds of the sugar, the second half - 1/3

So if you're making 10 gallons of beer that if collected normally would yield a beer at 1.050 you would see this:

Total gravity points = 500 (10*50)
1st 5 gallons = 335 gp / 5 = 1.067
2nd 5 gallons = 165 gp / 5 = 1.033

 

OP: You might want to state whether you are a batch sparger or a fly sparger. You're getting advice on both, and it's not interchangeable.

 

I partigyle. First runnings with ~66% of sugar is a nice strong guy. Then have capped or tossed in a < half # of different specialty malts (aromatic, melanoidin, Special B) to the second run (66% of the 33% left

Result one monster beer (high ABV), one session beer I can have sooner