This is the first time I have ever brewed w/o putting the hops (pelletized) in a bag during the boil. I threw them directly into the wort and, admittedly, I failed to filter out the bulk of the trub when transferring to primary (experimenting with different techniques). Whether or not its the hops, cold break or hot break, I am now enjoying a smell during fermentation reminiscent of a cat box. Its an oatmeal raisin porter, which I have done before without any problems. I also used the same yeast the last time- British Ale WLP005. The only variables (obvious, anyway) are my failure to remove the trub, and my decision to not use a grain bag to keep out the hop sediment. There is a lovely layer of krausen on top and the whole business seems to be in order, but there is just a very strong odor going along with it... perhaps it's the raisins?