Has anyone had a yeast cake that kind of looked like gravel? Here are two pictures of my APA with US-05. One is of the carboy for a reference point and one is a close up of the yeast cake. I've never seen this before.
I had this happen with WLP-380. If I remember correctly US-05 is the same as WLP-001. I'm surprised to see this with that yeast but I doubt it effects your finished beer.
I had my Pumpkin Ale look like that while using Nottingham Dry. Tasted great. Left it alone for 3 weeks. Bottled and tasted great. i think it is just co2 escaping from the bottom carving through the yeast cake.
I just had this as I transfered my milk/oatmeal stout to secondary today. Used Safale US-05. Just started to search for some info on it. Mine looked like, but more extreme. Large hard chunks of brown gravel looking stuff about 1cm side at the most. Kinda odd, my last batch using the same yeast didn't do that. Beer is fine though, tastes great. Should have taken a picture though.
This has happened twice to me. I just assumed it was a nice flocculating yeast with the addition of Irish moss at 10 minutes. I used Nottingham the first time and this last batch, about 8 days ago, looks the same with US-05.