Originally Posted by EvanLouis
..a bit of sediment floating on top.
Thats a bit of an oxymoron, don't you think?
If it looks like yeast clumps, it's normal. You can poke them down with a sanitized object or shake your fermentor a bit to try to get them to drop.
Cold crashing would be to cool your beer to a near freezing temperature so that yeast and other particles drop to the bottom of the fermentor. If those yeast clumps haven't broken the surface tension of your beer, they will continue to float even after cold crashing, so again, just find a sanitary way to push them down or just avoid them when racking your beer for packaging.