Sorry to disagree with every one but the ratio of yeast will
not cause his/her problem. I have been using a full packet of yeast
with no problem and 2 cups of sugar into a 1/2 full Gallon bottle.
I will agree that temperature COULD be a problem if it is much
under 70 degrees F. However from experience I would look for a leak in
the air line or a clogged air stone. If the bottle is expanding then
then it is a clog. Otherwise look for leaks.
Dennis