Opaque Beige-colored foam?

Hi all,
One of my batches of cider looks a little bit different than I've come to expect-- the foam on top is thicker and a little bit darker in color than other batches I have made, as well as the other batch I have going right now. This cider was particularly active in fermentation, and in fact fouled up the airlock yesterday so that I had to re-sanitize it. The foam had already looked off before that though.

My question is this- is it likely that something is wrong with this brew, or is it just particularly active? Underneath the foam the cider is still bubbling very happily. What are the possible things that could be going on, and what would they mean?

Thanks for all your help!

Sounds all normal to me. I know that when I pitch juice on an existing yeast cake, it usually shoots brown foam up into the blowoff tube. (And into the star san tub) It's called Krausen. It's usually more prevalent in beer brewing, but you will get it in really active cider fermentations sometimes too. You must have really good conditions and happy little yeasties in there

Great. That's a relief to hear. Thanks very much!