I see no problem using stainless steel, wood, aluminum or plastic to stir your FF. I uses a large aluminum spoon to stir my FF all the time and a wire mesh strainer for draining the FF and have no problems. The spoon is just as bright as the day I bought it, if there was a reaction going on the spoon would lose it shine, the wire mesh strainer would also discolor. That said I do rinse everything every time it is used. Where I live there is high humidity which slows drying of anything but I still have no problems. It would take time for any chemical reaction to start, the FF does not have strong enough chemicals in it to react by the simple stirring of the FF. I have been using my plastic containers, wire strainer and now the aluminum spoon as long as I have been fermenting, I do not have any sick chickens, nor any chickens with the runs and the eggs are still the best. Oh and the chicks hatched from broody hens that eat the FF are good strong chicks that are not deformed in anyway and they have become pullets laying eggs which are good eggs too. The large perforated spoon the I use in the slop bucket still has the magic marker on it after long use. That said, I ferment cracked corn and standard layer feed for 4 days and I use the drain liquid as a starter for the next mash, what is the chemical properties of the FF is not known by me, the chickens eat it, lay awesome eggs while the meat produce in the meats chicks is better than any store bought, what else can I say. . . . . . . .
