<<Disclaimer: Verify this information before applying it to your situation.>>

Yesterday I posted a quote from an allergy book telling you to add the
baking powder or baking soda to liquid before adding it to batter. What
was meant is that the usual way of adding those ingredients in a batter
is to add it with the flour.  They are recommending adding it to the
liquid rather than to the flour.  For one thing, it will give it a boost
faster, making it lighter.  The gf flours do tend to be heavy and gritty
and this is supposed to help alleviate that.