Saison stalled?

[IainM]

That could be fusels and if it is then you're pretty stuffed. Those won't go away.

Pitching too little yeast, not aerating enough and letting it get too hot could all cause that (although I've heard aeration isn't as much of an issue with dried yeast)

I fear you might be right, and the reason is because it was too hot. Now you mention it, it had zero head. Literally nothing, and its probably because of fusels.

 

[serum]

Yep sounds like it. There are some good diy ways of keeping the heat down. It seems more of a risk with big beers.