Bread-Bakers v098.n013.20

I know that citric acid (AKA "sour salt") has been used to imitate 
the sourness of sourdough bread.  I have some in the house, leftover 
from making cabbage rolls, and would like to try it in bread.  Can 
anyone tell me what quantity to use in how much flour?  I know the 
stuff is potent, and don't want to overdo it.  

TIA


Harper *** Robin Carroll-Mann
harper @ idt.net
"Mostly Harmless" -- Douglas Adams
Harper's Bread Basket http://www.geocities.com/Heartland/3967