Bungs and airlocks usually best, but if you are 100% sure fermentation is done and it's not gassy, I guess you could cap it. I always airlock everything, even wines I'm aging for 6 months or more.
Adding more fermentables is up to you- I wouldn't this time but maybe do it next time in one gallon.
__________________
Broken Leg Brewery
Giving beer a leg to stand on since 2006
|