off aroma - old yeast?

I brewed a couple of batches (cream ale, pale ale) using about the same approach as last year. The recent batches have an off aroma, and perhaps an off flavor. Not real bad, but certainly there, and it doesn't seem to dissipate after about two months in the bottle.

I used washed 1056 that was about 6 months old. Last year I used new 1056 or washed and immediately used the yeast from the previous batch. Also, I was using LME but now do PM and use DME. I'm about to bottle a bock (also a repeat from last year) and it doesn't seem to have the off aroma.

What can cause an off aroma? My best guess is something went bad with the old yeast. Has anyone experienced off aroma from old yeast? How long is washed yeast good for?

what did it smell and taste like? we are not psychic here.

I recently had some "infections" and have been trying to narrow down the cause. I think it might be coming from old washed yeast (6+ months old). It is not as viable as new yeast and you could be severely underpitching. 2 symptoms of yeast problem are no head in the beer and bandaid, medicinal taste. The last time could be attributed to chlorine but it wasnt the case in my situation.

Thanks for the responses. The aroma is hard to describe but earthy and yeasty come up. One person described it like an overdone German or weisse beer. It doesn't have the medicine smell.

Taste in the American pale ale is pretty close to what it should be if you don't sniff with the sip. I attribute this to the hops overpowering the off flavor. The cream ale does have a little off flavor. The off flavor is like the aroma (no surprise). I split the batch at bottling, doing half as vanilla cream ale. The vanilla is still evident, though somewhat muted.

I pitched the sediment from 1 1/2 pints, more than usual figuring viability would be down. There was still a bit of a lag in fermentataion, maybe 3 days (I didn't record the details). Head is fine, and FG was good at about 1.011.

These beers are still OK, just not really good like previous batches. I've only done 20-odd batches, so I'm still learning and appreciate any input.

how long did you leave the beer in the primary? how long in the secondary if you even used one? what where the fermentation temps like?

Was in the primary for about 4 weeks, no secondary. I ferment in a temp controlled small room, holding the air temp at about 63°F. I don't measure liquid temp (yet), but fermentation was relatively calm - no krausen in the lock for these batches.

So did you ever figure this out?