I have done a "sour mash" with the turbo's with modest success. Outof curiousity, I poured the left overs of my stripping run into one of my fermentation buckets to cool, and then next day I poured that back into my unwashed carboy that I had used to ferment the white sugar turbo. ie there was a good inch of sedimet in the bottom. Topped that up with water and sugar, and let it go. It took a little longer to ferment out but it did produce a reasonable batch. I then stripped that and then to really push it to the breaking point, I cooled the spent wash, swished it in the carboy to suspend the live yeast, and then split it into two carboys, topped with water/sugar and let'er rip. Now that run didn't really take. The wash even after three weeks was still sweet, and judging by the production (I have only stripped one carboy of the two from that test) maybe fermented out to 10-12% rather than the standard 18-ish%. Anyways, I guess the lesson I'd take from this is that if I am doing a straight white sugar run, I'd stick with one or maybe two runs per packet. Maybe if you were doing a molasses wash, you could get away with more sour mashing, but for white sugar, since the PH/trace nutrients all come from the yeast packet, stretching doesn;t really work well.