Little concerned with brew.
 

Im currently brewing my kolsch recipe. I noticed during the sparge that there was a gray film on the top of the grain bed. The grist is 10 lbs american pils. It was visible again at the onset of the boil sitting on top of the foam.
Ive been all grain for a while now, never have seen this. Any clues?

I wouldn't worry about it,,,,I suspect it something to the effect of super fine dust or some other insoluble particle....I've seen it on a few of my mashes and boils with no Ill effect.

that's normal. you get a lot of that in decoction mashing especially.

Yup, like this.

Attachment 60266

Thanks guys. I searched around and found another guy whos hbs had gotten a new mill. I crushed my own for that batch for the first time. Ill open up the rollers for the next one.