English Barley Wine+Small beer-one mash

how would one go about calculating a large and small beer? I want to do an english baley wine with the first runnings and a mild of sorts for the second runnings. How do i go about calculating this and has anyone ever done it? I know of anchor brewing but otherwise i cant find much. Any help would be appreciated

This thread may help:
https://www.homebrewtalk.com/f36/lets-partyyyy-gyle-pumpkin-porter-ale-one-mash-74927/

The rule of thumb that has always worked for me is that the first 1/3 of the runnings contain 1/2 of the gravity. So if you have enough grain to get say 12 gallons of 1.050 runnings, the first 1/3 (4 gallons) will have a gravity of (50 x 12 / 2 / 4) = 1.075 and the second 2/3 (8 gallons) will have a gravity of (50 x 12 / 2 / 8) = 1.038. With my system I usually aim for a 3 gallon batch of the strong ale and a 5 gallon batch of the weak.

You can always pass some runnings from one pot to the other if you need to correct the gravity. You can also use sugar/extract to boost one or both as well.

Hope that helps.

I'd look at the small beer as a bitter, probably in the ordinary or special gravity.

The way I do it is set my mash thickness such that my first runnings will be the entire big beer preboil volume (of course, without going over 2.5qts per pound). For giggles, let's say 20 pounds of grain, 40qts of strike. After losing about a half quart per pound of grain to absorption, you'd run off about 7.5 gallons which is about right for a 2 hour boil.

Then sparge with about 6.5 gallons and use that runoff as your small beer.

In software, I setup two recipe files with the same grainbill. In the first, I set efficiency to 60%. In the second, I set it for 25% which is approximately what your small beer OG will end up as. Once I do my mash/lauter, I tweek my hop schedule on the fly in the software.

This will be interesting. Do you allow the small beer to keep mashing for an extended period or drain and boil right away?

Unless you cap the mash with fresh grain all you are doing is sparging, so do it just like a regular batch sparge.