Last night was the first time I've used one of the Coors/Miller kegs with homebrew. I had a batch of choconut porter that had been in there for ~6+ weeks. I put it in the fridge yesterday morning and last night I removed the top to relieve pressure, added the Co2, and poured a pint. The beer came out very foamy, almost like a milkshake. In a standard pint glass, all but the bottom 1/2inch was foam. Most of the foam died down, but the beer tasted flat. I poured that glass out and got another, making sure to open the tap all the way, and got the same with the next 2. Are porters too "thick" for the Coors keg? I left it in the fridge last night and I'll see if another day in the cold will help. I have a batch of pal ale in another, and I hope it's not the same as this. Any ideas on what, if anything, went wrong?