Used older yeast and now I'm having second thoughts...

Brewed a beer this weekend and to my dismay I opened the fridge to find I didn't have the yeast I though I did. It was late Saturday night and there' no place open on Sunday. All I had on hand was some yeast that I'd washed and saved that was pretty old. Maybe 6 months? It didn't look fresh and white. I also had a white labs vial that a friend had given me. I don't know how old it was but he said it was "pretty old".

I smelled them both and they didn't stink so I figured old yeast is better than no yeast and dumped them both in there and gave the beer some good shakes and went to bed. No activity the next day. Still nothing this morning so I picked up a pack of Notty on the way home. Low and behold there's a little krausen on top and a couple of occasional bubbles. I was debating on whether to add the notty and took the air lock off to give it a sniff. It was pretty stinky like corn. DMS?

Now I'm starting to question my decision. There's alot of the darker yeast sitting on the bottom of the carboy and I'm starting to wonder if I should rack it into a new carboy and go with the notty to help the old yeast along.

Any thoughts. Thanks.

First off, you probably needed a starter to awaken the dormant yeast and grow new yeast.

I'd probably let the yeast ferment for a week or so, check the gravity, taste the beer, and then decide whether to add more yeast. Active fermentation can drive off DMS, so I wouldn't worry too much about the corn aroma at this point.

what he said ^^^

Yea, the yeast is old so with no starter so there is going to be a bit of a lag phase. The only risk is that you may have (because of the age of the yeast and no starter) under pitched and that might effect the flavor.

Thanks guys. I ended up adding half of the Notty. I'll use the other half for a brew this weekend. Ferementation was pretty strong before I went to bed and very strong this morning. A few inches of Krausen and a bubble every second so I'm breathing a little easier. I'm probably make it a point to make sure I have the proper yeast before I brew next time. Thanks again.

Well, this beer has been kegged and generally speaking it seems to be "not so good".

It still carried some DMS aroma after fermentation although most of it seemed to have blown off. I actually scrubbed the rest of it away by switching the gas and beverage out fittings of my keg and slowly bubbling CO2 through the keg. Now the beer smells OK.

The taste however is slightly dissapointing. This was an altbier so the only thing that should have been there for taste was malt (no hops). The malt seems to be there and my initial thoughts are "this tastes like beer"... but there is an after taste that I don't care for. Some kind of blend of medicine/band-aid/hot dog/ham.

Not sure of my temps because I was fermenting in my basement around 70 deg. This is my usual method which hasn't caused any problems. I'm using carbon filtered water so chlorophenols don't seem to fit. I'd say this is probably a result of stressed yeast creating some off flavors. Does this theory make sense?

This is a beer that I brewed for a party next week so I'm a little unsure of what to do with it.

I'm considering dry hopping it. I know this doen't fit the style but it might help to mask the flavor a bit. I know that dry hopping won't add to the "flavor", only the aroma. I've got a freezer full of hops so I'm not worried about "wasting" hops if I end up dumping it.

Thoughts? Thanks.