Last weekend I brewed a Belgian Quad with a 36lb grain bill, I had my 70qt cool max filled to the top.Sunday after brewing I decided to try to make a sour mash out of the second runnings of the Quad.
I added 7gallons of 150º water to the spent grains raising the temp up to 125 then tosses in a hand full of un-milled grain, and let it sit till yesterday, yes 6 day's. I drained off 5.5 gallons and boiled it with 30g of Saaz at 60 min. I'm not sure what the SG is for the beer, because I'm wondering how the lactic acid would effect my refractometer but, it read 17! I doubt highly that its 1.068. probable more like 1.035.But it has a good clean sour note.
I grew up a starter from the dregs from a bottle of Sierra Nevada killerwisen, and pitched that in to the 4.5 gallons of beer I got out of the kettle.
Fun little experiment, I think Its going to turn out well.