This happens from time to time with some of my beers.
The first time it happend I usually pull off the gas line of the keg, and run gas into the beer line for a few seconds to try and push the hops out of the poppet valve and the dip tube.
If that fails, then you'll need to remove the Keg plug assembly, poppet valve, and dip tube. Clean and flush out the assembly, Poppet valve, and dip tube with a little PBW, rinse, sanitize and re-install.
Last edited by Glibbidy; 04-15-2008 at 12:36 PM.