1- the temperature is 2 low, I would suggest placing the bottle with the solution into a water bath and adding a heater so the temperature stays at 80-90 degrees.
2- Check the yeast packets, they contain expiration date
3- you can either try soap test where you get a water bottle with some soap in it, place it on the spots like the caps of the bottles and see if you get any soap bubbles = leak
or you can just place the bottles under water and squeezing them lightly to see if theres bubbles like that..
4- since you are getting bubbles that means that the yeast might be working but as #1 said, the temp is 2 low
2- Check the yeast packets, they contain expiration date
3- you can either try soap test where you get a water bottle with some soap in it, place it on the spots like the caps of the bottles and see if you get any soap bubbles = leak
or you can just place the bottles under water and squeezing them lightly to see if theres bubbles like that..
4- since you are getting bubbles that means that the yeast might be working but as #1 said, the temp is 2 low