Unfiltered beer?

So I had one of my favorites last night, König Ludwig Weißbier. It was in our fridge sideways. Before I poured it, I noticed a sludge on the side of the bottle. We don't usually keep beer sideways after an explosion at the last place, even though it probably makes little difference (sideways vs upright).

I guess that sludge is the unfiltered yeast? It was a substantial amount, maybe an ounce in half a L.

Good stuff, but not as tasty as I remember. Last time we walked a few miles before we had a König. Actually, we walked a few miles on local trails last night as well, but it was not super hot this time. Who knows. Still good stuff.