I'm thinking that it takes more than just a couple of days to ferment the flakes, unless I'm missing something. I grind the flakes and wait, right? Does it matter if/how I use the box in the meantime?
I had put some red flakes in the chamber yesterday. I couldn't remember if I ground them yesterday though, so I ground them first thing today, and then opened up the box and got the blood. So it definitely doesn't take more than a day to make.
(Heh, when I wasn't even trying for it in the first place - just trying to make some red dust for my 'one of everything' collection.)
EDIT: looking at my logs, it does look like I had ground it yesterday after putting them in the box.
Here's what I did:
I think Al might have it here. I had put flakes in the pouring chamber yesterday and ground them. I was planning to wait a few days, but after reading Al's post I did another grind and opened the chamber to find blood of the ancients. I had been fiddling around a lot with the puzzle before in unsuccessful attempts to get the blood, though, so it's possible that some of those preliminaries might have unlocked this possibility. But, at least the final stage looks like it's very likely to be: grind, rollover, grind, voila!