self rising flour has addition of baking soda and some dry form of acid.
they cancel each other out and create CO2.
I would think that it should be fine for a UJSM style wash. make a few extra bubbles in the beginning, but will even out soon enough.
Give strong drink to him who is perishing,
And wine to those who are bitter of heart.
Let him drink and forget his poverty,
And remember his misery no more.