Of all my GF beers, this one was the most popular with my non-gluten free friends.
5 Gallon Batch
1/2lb of Amaranth soaked and then boiled for 30 minutes
1lb of dark toasted millet
both steeped in water at 145 for 45 minutes, strained out, sparged and then bring to boil.
At 60 minute mark add:
3lbs tapioca syrup
3lbs brown rice syrup
At 15 minutes left add .5oz tettnang
At zero at 1oz hallertau
2lbs D180 syrup
Pitch WLP838 at 70 degrees
Note WLP838 in 5 gallons is less than 2ppm of gluten. You do not have to use this yeast. If I brewed it again I doubt I would use it.
Also, you may consider using 1lb D180 and 1lb D90 to add more complexity of flavor to this beer.
Finally, I highly recommend serving with 1/4oz of cold coffee added to your beer when you pour it out of the bottle. I use 16oz bottles so adjust accordingly. The coffee makes all the difference.