brewing sorghum beer

i have made 3 batches of sorghum beer from the syrup purchased from williams brewing co.
i like most beers from Guinness to mich ultra the only beer i truly hate is kentucky ale
i like the taste of my sorghum beer but it seems to turn out a little flat each time.

i have been carbonating in the bottle
in the last batch i added 1/2 cup corn sugar and 1/2 package of yeast.

the carbonation is ok but could be better.

is anyone out there making this beer? i am new at brewing and would really like some feedback from anyone brewing sorghum beer.

My girlfriend has celiacs, so I just made some sorghum beer. I was pretty unimpressed, i need to change it... It's tart, not even totally carbonated tho, my gf couldn't wait. Its either horribly wrong or needs to mellow.