Two weeks ago I brewed a barleywine with an OG of 1.092 and put it into a carboy. I pitched a 2L starter of re-harvested Wyeast Scottish Ale yeast (w/ yeast nutrient and zinc) as well as a Mason jar of freshly harvested Wyeast 1056 to ensure sufficient yeast population (probably a little over board, but it’s a barleywine). After fermentation had slowed (4 days), I added 1.5 lbs of can sugar and 1/2 each of dried dates and figs, which I chopped and boiled with the sugar and water for half an hour before pureeing and pouring through a sanitized funnel into the carboy. I wanted to bump up the gravity, dry the beer out a little and add a little complexity with the fruit through this process. This should have bumped my gravity up to somewhere in the range of 1.105-1.110.
Last night I took a gravity reading before adding my dry hops and it came out at 1.005 for a final gravity. This gives me almost 95% attenuation and 13-14% ABV - both things that those yeast strains should not be able to achieve (my hydrometer reading is correct - I double checked my calibration and readings right after). My thought is that I got a wild yeast, though I smelled nor tasted any off flavours in the beer (though it certainly is dry!).
As a test (and a hope to add a bit more residual sweetness) I boiled some LME and brown sugar and poured it into the carboy last night and this morning it was bubbling again slightly, which means that there is still fermentation despite the 13-14% ABV - which again makes me think wild yeast, unless I somehow created super yeast with my over pitching and mixing of strains.
Thoughts? Anyone ever seen these yeasts hit these sort of numbers or are my worst fears correct?