No, this isn't a "my barleywine is bigger than yours" thread. But I was wondering how high everyone would be comfortable pushing the limits for an OG on a beer that used no simple sugars or incremental feeding or anything else of that sort. In other words, at what point would you be concerned that the OG would be so high that the beer had little chance at finishing out at a drinkable FG, and is more likely to stall out at the "alcoholic malt syrup" stage.
Here's my scenario that has me thinking about this. For my next beer I am brewing a barleywine using an iterated mash. Basically, for a 3-gallon batch, I am planning on mashing 8 lbs of grain around 160F (for a high Alpha rest), then pulling the grain bag, and replacing it with 8 more pounds of grain. I'm hoping this will get me down to Beta rest temps (148ish), where I will hold for a long mash to max out fermentability.
I'm using 60% as a ballpark effiency, which would give me something in the 1.125 range for an OG. The thing is, I've gotten as high as 86% efficiency on barleywines using 8 lbs of grain in the mash before. If that happens, then I'd be up over 1.170 for my OG. Even with a big pitch of yeast, followed by a second active starter pitched 7 days later, I have a hard time imagining that this would finish as low as I'd want.
What would you use for your upper limit for the OG on an all-malt barleywine?