I have been brewing a few batches of sodas with my daughter and was thinking of having a keg of ginger beer on tap. We made a gallon at a time using 1.25 to 2.5 oz of grated fresh ginger, depending on how much ginger flavor we wanted, 1/2 a lemon juiced, and about 1.75 cups of sugar simmered for about a half hour. It's a pretty simple recipe, but makes a pretty good ginger beer. This also was for naturally carbonated ginger beer. If I force carb, I will probably cut the sugar amount down. Good luck and let us know how it goes and what recipe you use.
I think I'll be making a few tweaks as I go, but I made my first batch last night. The recipe is basically a guesstimate based on several recipes I've seen, but I should be able to dial it in quickly over a few batches.
1 medium hand of ginger, peeled and chopped (weighed 1.5 oz/43g of prepped ginger)
125g light brown sugar
This was added to a cup of water and heated to a boil in the microwave in an oversized coffee mug
Zest of 2 limes added as a "flameout" addition to the boiled syrup, then covered with plastic wrap and allowed to steep about 90 minutes
The juice of the 2 limes was added to a 1-liter soda bottle, then the strained ginger mixture, then topped off with filtered, cold tap water. I force-carbed to 30 PSI and threw it in the kegerator to chill overnight. I'll give it a taste tonight and report back. The nice thing about a 1-liter batch is that it is pretty much 1/10 of the size of my 2.5 gallon kegs, so everything should scale up easily to a keg.