Stir paddle tarnished in StarSan
 

Hey gang,

I bought a plastic stir paddle to aerate my wort, it has an aluminum shaft and after being the StarSan for about 2 hours, the shaft is now black. It has a metallic smell to it.

Can/should I clean it off. If so with what
Will it hurt anything

Toy4Rick

Aluminum is a reactive metal that when comes into contact with acid can begin to dissolve. You may want to get a different paddle. The more concentrated the solution the more violent the reaction. If the aluminum is coated it may take awhile to see any reaction at all.

Oh and I wouldn't use the paddle, if I remember right the aluminum turns to aluminum chloride, the acid begins to create hydrogen gas. The paddle was probably bare and had no oxidation on the surface or any other protective coating

I left my carboy brush in a carboy with starsan for a while and I guess the metal for the brush is aluminum because it started turning colour too. I am learning:(

Aluminum boil kettles turn black with use. I would think it would be fine.

Yeah you cant use aluminum with starsan...the acid eats the aluminum. Found that out the hard way using a carboy brush made of aluminum once. I believe there are other sanitizers you CAN use that don't do that.

Aluminum kettles turn black because of a different chemical process. Its just plain oxidation. Star San is an acid that deteriorates the metal itself. It actually creates hydrogen gas by trading off molecular structure of the aluminum.