Strange Brew

It's been a tough week for me brew-wise. It started with a stuck fermentation in my dry stout after only achieving about 50% attenuation (using white labs irish ale yeast). I tried rousing up the lees to no avail. On a separate note, I was all set to brew a dogfish head 60-minute, until I pulled out a frozen package of Wyeast Ringwood Ale yeast from my overactive fridge. I did not want to use the frozen yeast in a new batch, so once it thawed I made a starter and pitched into my stuck stout. Fermentation has begun once again, but I have no idea what to expect after re-pitching with a completely different yeast. Any ideas? What are the differences between the two yeasts? Will this completely throw off my stout?

I am a total newb when it comes to brewing, but not drinking. From what I understand, stouts can get away with a lot of different flavors in the name of "complexity" so I'm sure it will be good, if not great (unless there's something about those particular yeasts that I don't know about -- wait for someone who knows what he or she is talking about to respond).

From looking at the Wyeast site, they are not terribly different, at least not enough that it will make a huge difference in the beer. Both strains are recommended for dry stouts, so you should be ok.

The flocculation is noticeably higher on the Irish Ale yeast, but other than that, they are quite similar. I do have a couple of questions though. 1) What temp are you fermenting at? 2) When you say stuck fermentation, can you tell me a little more specifically what you are seeing that makes you say it's stuck?

I started with an OG of 1.038. It spent a week in primary, then two weeks in secondary, but when I checked the SG, I got 1.020. I waited a couple more days and it stayed right at 1.020. I checked my hydrometer in water to make sure it wasn't the problem, then I tried the beer. Nothing tasted out of whack except for extra sweetness. I have been keeping it around 68, although I know there was one particularly cold day when the heat was left off. I am assuming that was the culprit.

You should have saved that second packet of yeast. It more than likely would have been fine. It is a good idea to keep a couple packets of dry yeast like S-05 or Nottingham on hand for these situations. They are a whole lot cheaper than pitching another smack pack and are still excellent yeasts.

If you are an extract brewer, see this thread. It may clear some things up for you.

Also I second what double_e5 says about keeping dry yeast around for this purpose.