Balls.... have I messed up?

[Chris Wooffindin]

Evening everyone,

I'm hoping someone can give me a bit of help? I've been fermenting a pale ale and decided to do a rare thing for me and dry hop. To weigh down the hop bag I decided to be 'clever' and use some 16mm stainless steel ball bearings. However, when I've come to rack the beer into the kegs, I fished out the ball bearings from the hop bag and they're basically tarnished black.

What could cause this? Is it something to do with passivation (or not passivating because I didn't do this..)? Have I ruined the batch with some poisonous contamination? It tastes fine. Any help or pointers would be very much appreciated.

Many thanks,
Chris

 

[An Ankoù]

I had a similar experience when I boiled some water in an SS pot to dilute a beer the next morning. Everything above the water line was tarnished.
Looking forward to reading some comments on this.

 

[Jamthesun]

A few things you might want to consider:

1/ there are different grades of stainless steel.You should only use culinary grade stainless steel. Your ball bearings probably weren’t culinary grade.
2/ SS can corrode in damp,low oxygen conditions because these conditions prevent creation of the protective chromium oxide layer.
3/ Go for inert weights. Marbles are good.

 

[Alex.mc]

I think you answered your own question,
"It tastes fine"

That aside, as above there are many grades of SS, ranging from the type that will be fine left exposed to the atmosphere and rain without tarnishing, to the very resistant type that can be submerged in very salty and chemical laden liquids that have large temperature ranges. A chap I knew built model boats and used SS for the rudder shafts as many of them were used in salt water. He bought seawater relevant grade, and was fine for many years. Then one day customers began to mention corrosion, and it turned out the supplier had been sold some misrepresented SS of a lower grade. That was big trouble all down the chain.