I've divided the ingredients into 4 1 gallon recipes. I went ahead and brewed this today:
"GF Honey Saison" (1-gal)
8 oz GF rolled oats (steep)
8 oz sorghum syrup (30 min)
8 oz sorghum syrup (5 min)
6 oz raw honey (5 min)
.25 oz US Saaz (30 min)
.25 oz German Hallertau (5 min)
.75 oz candied ginger (5 min)
.5 oz sweet orange peel (5 min) (a little overboard on these two)
and ~1/4 tsp gypsum and Irish moss
1 full vial of WLP565 Saison
I did a 30 min boil in a very inexpensive 3 gal kettle I found at the grocery store for doing small brews. I vastly underestimated boil off, which ended up being around 40% if I reckoned it right. With Brewtoad I had an estimated OG = 1.050, IBU = 21, and color = 2*L.
The question I had was, how confident could I be that this will be completely GF? Not for myself, but for certain family members who won't consume anything prepared on non-GF counter-space(!). I'm thinking of the vial of White Labs yeast in particular.
[Update: turned out pretty well. It fermented close to radiator heat and went through all kinds of temp changes. The flavor profile is complex even for a saison. When I open the last bottle I'll update this with notes.