I just made a batch with Gnome extract. They call for 10 cups of sugar for a 5 gallon batch. I also wanted to experiment a little and get some more mouth feel. So I made some sweetener substitutions. I went with 6 cups of cane sugar, 2 cups of light brown sugar and 3 cups of clover honey. In addition, I added 1 tsp of vanilla extract and 4 tbsp of malto-dextrin.
With this combination I nailed the exact sweetness and mouth feel that I was looking for on the first try! How often does that happen? I really think the addition of the honey and the malto dextrin made the difference in the special sweetness and mouth feel of this batch. Everyone that has tried it has loved it!
I usually use the one gallon jugs of pre-sweetened Sprechers syrup, which in my opinion makes the best 5 gallons of root beer that money can buy. I didn't have any left so I had to go with Gnome, which I can get locally. You can only keg with the Sprechers syrup though because it has preservatives that will not allow for carbonating with yeast.