Sometimes if the yeast cools rapidly, they will go dormant.
At 65* their metabolism will be a little slower. I haven't made champagne before, but wine yeasts tend to take off a little slower.
The yeast will keep producing CO2, probably to the point where the bottle would explode, which is over 100psi. More than enough to push gas through a ceramic diffuser. I use a ceramic diffuser with no issues, granted the three or four I have used were all the same brand. Different density diffusers may cause an issue, but the bottle would rupture or you would blow a line off of a fitting if it required more pressure than DIY CO2 could provide. I keep seeing people posting that ceramic diffusers do not work with DIY CO2, but I have never seen a warning about anything rupturing, which makes me doubt that their systems were sufficiently air tight. Switching over to a different diffusion method with lower pressure would force less gas out the leaks and produce bubbles in to the tank, which could lead people to believe that it just won't work. Either that or they are parroting what other people have said.
If you squeeze the bottle is it solid, or can you still squeeze it like you just put the cap on?
If it is relatively soft, you are not producing CO2 yet. Try placing the bottle in a pot of warm water (while still connected) for a little longer than an hour. If you shake it up a lot (when initially setting it up), you will get more oxygen in to solution. While oxygen is present, they mostly reproduce, once the oxygen is used up, they start producing CO2. Dry brewing/wine yeasts always took a day and a half or longer to get started for me in the cooler months.
If the bottle is relatively hard, try dripping soapy water on the connections, if you are getting bubbles, that is where your leak is. (there may be more than one)
If you have a check valve, verify that you have it installed the correct way.
If you have opened it at all, it will take a while for the pressure to build back up.
Does your tap water have chloramine? I wonder if that could have killed off the yeast.
I usually feel kind of guilty using the quick reply... my replies are rarely quick.
Last edited by Darkblade48; 04-25-2014 at 05:18 AM.
Reason: Back to back posts