Been out of the hobby for 15 years. I started up again on July 6th. a NB Irish Red Ale. It has been in the bottles for 20 days. I sampled today, it is very clear and tastes great but not much carbonation- no head at all. I primed the 5 gallons with 3/4 cup corn sugar. The temperature has been 70 degrees. Will it get better? any way to fix it?