Originally Posted by aggieotis
As far as gf grains go, there's no standardization so your guess is as good as mine.
There isn't for any grains, it is based on efficiency and conversion.
Efficiency determines how much of the sugar is derived from the grain. As long as your process stays similar, this number should be similar as well. You will have to test out your system to find how it does and then use that number going forward.
Conversion determines how much of the sugar is fermentable. This is the area we struggle with in GF brewing, because this depends on amylase enzymes.
Both of these depend on your individual mash characteristics.
For instance, steeping uncrushed grains has a very low efficiency (around 10%) and 0% conversion. With crushed grains, the efficiency number will go up considerably (50%+) but the conversion number remains at zero. Add enzymes and the conversion number jumps up.