question about head

Before bottling I added 3/4 cup priming sugar to my bottling bucket. The I have drank about 3-10 a week since then. My question is, only 2 or 3 beers actually had a head of any kind. All of the bottles have hissed when i opened them, so I think I got the caps on tight enough. Any ideas why they would be inconsistant?

Head retention is a completely different thing to carbonation.
How do you brew and what recipes are we talking about?

The first thing that comes to mind for me is your glassware. Any hint of soap residue will kill the head. If you use a dishwasher, or use soap on your glasses, that would do it.

The next thing I would consider is your recipe. Some ingredients tend to encourage bigger heads- like wheat, or carafoam.

Either of those two things could be an issue.

The most likely thing I can think of is cleaning practices. If you clean your equipment and bottles with dish soap or other detergent cleaners and don't rinse all of the residue away, the residue will kill the head on your beer. Where you've said that your beers are carbonated (that's where the pfft comes from when you open the bottles) but only some are getting a decent head while others aren't I would have to say that the ones with a decent head are in bottles that were rinsed more thoroughly and the ones without head are in bottles with residue. Something else that can cause inconsistent head is poor mixing of the priming sugar in the bottling bucket. How did you mix your sugar?

***Damn, Yooper beat me to it!!!***

Even though my glasses are clean I always rinse them under cold water before filling. This is a practice I learned in Germany.

Thanks for the replies, the soap on my glass thing confuses me. I will use the same glass all night and only 1 will pour with any head at all. I also rinsed all the bottles the same way. I probably could have mixed the priming sugar a little better. As far as the recipe, it was a can, add water, dextrose, and yeast. Muntons light american lager, my LHS "gave it to me" when I bought all my gear.