Originally Posted by Zero
The recipe calls for Wyeast 1084 Irish Ale yeast.
I disagree with the posts above completely, but in the end your experience is what matters. Brewers make wort, yeast makes beer
. WhiteLabs, and Wyeast both make products that are superior to dried yeast.
There is a reason that they (White Labs and Wyeast) sell a hundred different versions of ale yeast, and the dried stuff comes in a single packet called ale yeast.
However, I will admit that making an oatmeal stout, which is a traditionally English in nature will probably succeed with very few problems considering that S-04 is an English Ale Yeast. Cool your beer, open your packet, and drop it on top. They mention something about heating it up in water, to wake it up, but as long as you aren't trying to wake it up at 50 degrees, mid to low 70's will be just fine.
I'm not here to knock extract brewing, but, you are already making and taking shortcuts in the brewing process by using extract. So, make an effort to use the best materials you can where your grain bill does not apply. Find quality hops, use liquid extract if you can get it fresh, and use a quality yeast. You will have better beer, and feel better about brewing it again.
One last thing. This is a note on your recipe. I'm not sure why you are using DME instead of amber extract. There is some modern precedence to use pilsner malt along with debittered black malt to make Porters(Since the late 1850's). Historically,(Before that) Mild, Brown, Biscuit and Amber malts would have been used to achieve the dark color. My experience with DME, was that it was lacking.. a lot.... of character. I would suggest an amber, or medium liquid extract, for which the conversion from 5.75 lb DME would be 7.0 lb liquid amber.
Good Luck Brewing.