Got five quarts of GC for the wifes Aztec tonight. Months ago I went in search of this stuff but, only found the Made in America Yellow label brew. I guess my local Autozone got rid of the U.S. stuff or sold it off cheap. Numbers and letters on the bottle were MO521. How old is this? Asked the check out guy if they were going to keep carrying it, the guy said yes as far as he knew the would be. Can I run GC year round? The summers here in Kansas are over a 100 degrees alot. I know it can handle the winters. The summer heat is my only real concern. Please comment.