Well, it did referment very quickly after being transfered to one of the larger stock-pots and the extra ingredients and water were added. About an hour and the copper film was thick again. This was around 4:30pm today. I took my dye spoon and gently brushed aside some of the foam and I could see that the liquid was a mostly yellow/greenish color.
So yay! I took the pot outside and carefully removed as much of the copper film as I could and introduced the cotton yarn that I wanted to try dyeing.
The instructions said to let it sit for about 20 - 30 minutes, which I did, but I think it can probably be left for a shorter time than that. By the time it was done, it was starting to get dark (blast shorter days in winter!), so the one picture that I got removing the yarn from the dyebath is too dark to really see the color, but I can tell you, it came out a kind of dark green and very quickly started turning dark blue.
I squeezed out the excess carefully with rubber-gloved hands and set the yarn aside on the grass (I didn't have anywhere to hang it). I put the copper foam back onto the top of the indigo, stirred carefully and recovered the pot with the lid. When I came back outside after taking the pot back into my craft room, the yarn was totally blue. I have it hanging to dry in the extra bathroom shower now. It's a very dark, even-looking, navy blue.
Tomorrow afternoon, I'm going to dye some wool. I'll try to do it earlier in the day if possible so the pictures will be a little better...
Okay... so here's what I did for this dyebath, in case anyone might want to try this out themselves:
4 tbsp pre-reduced indigo (you can, and probably should, use less than that... like maybe 2 tbsp to start with, but that's how much I used), mixed with 2 cups of *non-sudsing* clear ammonia. (I used a large mason jar, but you can probably do this in a dyepot if you like... you're going to need a large dyepot of at least 4-gallons.)
2 packages of yeast with roughly 2 tbsp of sugar stirred into about 1 - 2 cups of warm water (about 100 degrees). This is to activate the yeast and get it working.
After 1 or 2 hours of letting all that sit, mix the yeast with the indigo/ammonia in the dyepot and fill the pot with approximately 3.5 gallons of water, or until there is only about 1.5-2 inches of headspace at the top of the pot.
Stir gently to combine all this stuff and a copper film will probably rise to the top pretty quickly. Let it sit for a little while. Some instructions said as little as 10 minutes are needed, others said overnight. I waited a little more than an hour and it was fine.
After dyeing, if the liquid looks more blue than yellow-green, it needs to sit a while to get the oxygen out again.