I had to give it a try. I have a ton of crafty stuff to get done before Christmas (in a WEEK) so I thought I'd add to that by spending hours staring at blue yarn waiting for it to exhaust.
I used Knit Picks Bare in a discontinued variety that is essentially Stroll. First, I had to divide in in half so the socks would match.
Then I rolled the other half into a ball. The tute told me to put tension on the yarn when winding into a ball. I think this was a mistake and resulted in the dye not being able to penetrate into the ball well enough. If/when I do this again, I'll put as little tension as possible. I mean, you don't want it just falling apart but that wouldn't really be winding it into a ball, now would it?
Also not in the instructions: soaking the yarn. The thing here is that if you use any more than a very small amount of liquid, the ball will float UNLESS it's been soaked ahead of time. So soak that puppy! There is nothing to lose. I'd add a little vinegar. What the hell.
Because I did this with blue, which we all know takes notoriously long to exhaust, I decided to do this in the oven instead of on the stove top. I wanted to be able to leave it for a long time, plus I do not relish the idea of burnt yarn. (I also like to use a probe thermometer and really be able to know what's going on.) I ended up with the yarn in a clear pyrex bowl on a baking sheet (to help prevent spills, which it did). I used Easter egg dyes AND liquid food coloring AND Kool-Aid to get the blue as dark as possible.
Easter egg tablets dissolving:
Yarn in the over with the probe thermometer. You can't tell here, but it's floating. While I do know that it's the concentration of dye to yarn and not dye to water that matters, I still used too much.
It never fully exhausted. I'll be interested to see whether or not I get blue fingers when I knit with it.
Then we got to the second-worst part: getting the wet yarn out of a ball and into a hank so it can dry. I don't have a niddy-noddy, which would have been extremely helpful with this aspect. It REALLY sucks trying to wind soaking wet yarn. Period. I ended up improvising and wrapping it around the baking pan I used in the oven. (It was cool, obviously.) I plopped the wet yarn balls into the bathtub (could have just as easily used the sink) so they could roll around without worrying about things getting wet/messy. By the time I was done, my arms were achy, my sweatshirt was, let's say, damp, and my hands hurt from peeling the yarn off the pan.
Over-all, I like the technique. I will probably try it again. I'm really interested to see how it will knit up! (It's going to be socks for my grandma.) I think there is definitely a learning curve. I'm not an expert dyer, so it is always an adventure. I think this could be done really easily in a crock pot.
If you want a couple more tutorials one dyeing with food colors and the basics, I recommend these two:
http://www.knitty.com/ISSUEfall02/FEATdyedwool.html is mostly about Kool-Aid dyeing.
http://knitty.com/ISSUEspring07/FEATdyeyourown.html is fantastic and written by the lovely and talented SamuraiKnitter. I have this article printed out and have referred to it quite a bit in my dyeing experiments.
There is also http://www.dyeyouryarn.com/index.html which is interesting. I haven't fully explored their site to the extent I'd like to be able to really endorse it, but it definitely seems helpful.
I can't wait to update you with how it knit up!