Do I have an Infection?

I brwed my extract bitter four weeks ago, its still in the fermenter. This is my 4th overall batch, and my 2nd of this kind, so I know what it should look and smell like. About 1 week in I noticed some weird spots floating at the top, it almost looked like a off colored mold. I noticed as well that the krausen didn't look like it did last time - not as big, long lasting, or thick. I smelled the wort probably a week ago and it reeks. It smells like old olive juice or something. I'm suspecting very heavily that I have an infection, but I don't want to dump it all out without being sure. Can anyone give me some info on whats going on here?

Thanks,

Each krausen looks different so that won't really be much of an indicator. If you have a nasty smell that could be bad. Tasting it is going to be your best indicator. Post some pictures!

Never dump your beer!

More than likely, and without a picture to see it, your "infection" is going to be what 99% of the other new brewer infections tuen out to be. Yeast rafts; little bits of yeast lifted by rising currents of co2 from the trub, that float on the surface of your beer.

They are quite normal.....

I remember reading Revvy's post when I first started brewing a while back, but I had since forgotten. Wise words... I'm 98% sure this batch is infected; I just don't think the taste and smell can be done away with.

Here's a pic.


Edit: Ok, the pictures isn't showing up for me. You can access it here instead: Infected Brew

The "spots" on the top were much more dense at the beginning, but have since settled out. I wouldn't even bother you guys with this if I didn't make the same recipe a few months ago and have noticed a lot of difference. This stuff just smells 200% different than my last batch and looks a lot worse.

Measure the gravity. Infections often take the beer to extreme attenuation. If you are better than 80% attenuated, bad sign. Doesn't look good to me.