Troubleshooting Yeast/New AG

[michigator04]

So I have brewed 4 or 5 batches of extract/partial mash that all turned out very well, but recently made the jump to AG (BIAB) and my first two batches with it have been really bad compared to the others. Both batches (Cream Ale, and Smoked Rye Pale Ale) had the same odd flavor that just seemed off to me. I think it might be related to the yeast I used (Denny's Favorite 50). I had attempted to follow the Wiki instructions for making a yeast bank to save some $, but with two batches in a row having a sour, funky, yeasty smell that was lasted into the final product, I need to reevaluate my process.

I am thinking the first thing I need to change is to get rid of the frozen yeast, since it hasn't performed well yet. The reason I think it is the yeast is that I noticed the smell/flavor really strongly in the starter. It fermented fine in the real beer, and got the ABV roughly in range, but both beers finished high (above 1.02, or about 10 pts high for each). I had read on here somewhere that mashing too hot can lead to unfermentables --> high FG. That could explain that aspect of the beer performance, but that doesn't explain the off flavor.

Any thoughts about what might be the source of the problem? Yeast? Contamination? Starter size/technique? Too many/not enough cells? Problem in the mash?

 

[bechard]

If you smell something off in the starter, its probably contaminated or bad yeast IIRC.

 

[Kaz]

I tried yeast washing once so far, it didn't turn out very well. I washed yeast from a brown ale and the a day or 2 later made a porter with it. Well, in the end, the brown ale turned sour, the porter soured during fermentation and I got rid of the washed yeast. I would say that if you smell a sour smell in both beers, and you used yeast from the same washing and the yeast smells sour, then toss the yeast and try fresh. The yeast seems to be the common element here, if that doesn't work, then I would look elsewhere.