Over-extraction?

[Cody]

So, I am increasing my skill at mashing (not to mention improving my beers) by using partial-mash techniques. The beer I made last night is a pretty straight-forward brown with Marris Otter, Munich, melanoidin and dark crystal malts and Amarillo hops. I plan on fermenting with Wyeast Trappist Blend followed by Brett. c. I somehow managed to drastically overshoot my gravity, ending up at 1.076 instead of the planned 1.056. My question is: how do I know if I have a problem on my hands? I've heard that there can be flavor issues when you get into the 90%+ efficiency range. Once this is fermented out, could I be looking at flaws even though I can't taste them now?

[animaldoc]

My question is: how do I know if I have a problem on my hands? I've heard that there can be flavor issues when you get into the 90%+ efficiency range. Once this is fermented out, could I be looking at flaws even though I can't taste them now?

This simple answer is don't sweat it. You're right you probably won't be able to taste it now. Wait until it's done then enjoy it -- the flavor concerns of over extraction simply because you have high effiiciency are a bit overblown -- it has a lot more to do with pH and temperature during sparging than pure efficiency calculations.

Speaking of calculations -- how much grain and how much extract did you use, and what was your final volume?

[Cody]

I used 6 lbs of grain and ~3.5 lbs of LME. Final volume was 5 gallons after topping up, so there's also the possibility that it wasn't mixed well, but that's unlikely to be much of a factor.