Does anyone know where to buy citric acid (sometimes known in cooking circles as sour salt) in sort of reasonable bulk? I'd like to get some to de-scale my espresso maker's plumbing and I'd rather not pay $5 for a couple of tablespoons of it in a fancy coffee store. Is this something that health food stores carry? Or does Whole Foods still have this sort of thing in the bulk department (if they even still have a bulk department)? Will a pharmacist still sell such dangerous chemicals? Hardware store under some other functional name?
I'll admit I haven't looked very hard yet. This just seems specialized enough so that someone would just know where or in what kind of store to buy it. I'm in Falls Gulch, so I don't want to go to Baltimore or Rockville for it, and I don't want to order from one of those on-line places that charges more for the shipping & handling than what the stuff costs.