I made a hard root beer that came out pretty decent. I used:
44.25% extract, wheat/barley blend
29.5% honey
10.25% lactose
3.75% molasses
7.25% 60L
2.5% Special B
1.85% Chocolate Malt
Ummm, I don't think those add up to exactly 100% but close enough.
20 IBU fuggles at 60 min
10 IBU fuggles at 20 min
US-05 yeast
OG about 1.095. My root beer was deceptively strong.
For the water I used a tea brewed from sassafras roots I dug up in my yard and a few oak twigs. This was to taste -- I don't know how much it was.
At flameout I added 1 tsp natural vanilla extract, 1" cinnamon stick, and 4 cloves per gallon.
I was going for something sweet, but not syrupy. That's why I added all the honey. The lactose helped some with sweetness and mouthfeel, but it wasn't enough, and I didn't think adding more was going to get me there. So at bottling I dissolved xylitol in boiling water and added it to taste. It really did the trick.
I have another batch fermenting, but I'm trying a different approach. Xylitol is so expensive, plus I would rather not have so much artificial sweetener, even though it's one of the better ones. This time I added 1 tsp dried stevia leaf to the end of boil, so I'm going to see how much I can sweeten with the stevia. When I get it into the secondary I can slowly add more and see what happens. I still might add a little xylitol because it added a nice slick mouthfeel. Also this time I did all grain, mashing really low at 148* and used 20% plain table sugar instead of 44% honey. I'll see how it works out.