Millet Single Infusion Hold

Today I tested a single infusion recipe using home malted millet.
420grams of Pale malt 3L
47grams or Carmel 20L

Crushed to a course flour.
Using 1 liter maple sap at a pH of 6.0 (right out of the tree) to 467grams grain.

Dough in at 65Cel (154.4F) for 75mins
The picture with the sieve is my "Lauter Tun" and the other is what was the result of the lauter sparge thru the filter bed became. The Lighter color is the clear wort and the other is a lot of starch that fell to the bottom. To my surprise the small batch was 13 Brix (1.056) WOW! one sip was amazingly sweet.

What was the gravity of the maple sap before adding the grain?

I don't think i could reproduce what you are doing because the only tree sap available in Florida right out of the tree is pine sap and my guess is it would produce very different results!

I've heard of a beer using pine or was it spruce needles to flavor the beer so the sap may be good too. Should tap one and test the brix out of it( LOL) The sap was 2.4 Brix from the tree so that's 1.0096 so 1.054-1.010=1.044 was the grain itself. Which is about right so single infusion will work but they're was a lot of starch on the bottom. I would think that with that much I would have almost 1 gallon trub to contend with in a 5 gallon batch. A conical fermentor would be good at this point to drain the trub before transferring to bottle or a keg for that matter.