Our marshmallow porter seems to have some type or mold or sediment floating atop the beer after 17 days fermenting in a wide-mouth plastic carboy. They look like flakes. Not fuzzy or spider-web like. Beer tastes and smells similar to usual, Preconditioning, but we’ve never had floaters like this before. Should we toss it or is it fine to bottle?
Unless whatever you're bottling is genuinely, horrifyingly undrinkable- I'd never pour anything out before bottling. At any rate- it won't hurt you.
It's really difficult to tell on a picture through a carboy- but it's probably normal coagulation of some oils and starches in your beer.
The rough picture may have some folks tell you it's a lacto infection- but based on the patterns and color I'd say that likely isn't the case.