Cotton Soaked in Soymilk

Had a question at the workshop yesterday about the soymilk process I use to get brighter colors in soymilk. Here's a basic rundown of what I do:

I usually buy the plainest soymilk I can get my hands on (vanilla attracts buggies we discovered) and soak wetted and well wrung out pre-mordanted yarn/fabric in just enough to fully wet the fibers. I usually do this in one of my white tubs, and I squeeze the material so that the soymilk penetrates it fully. Then I let it sit about 15min, moving it around and continuing to squeeze the soymilk into the fibers (so it doesn't penetrate unevely and doesn't begin drying in any one place). I wring it out, but I don't wring the life out of it (if that makes sense). I find it works better if it still has a little in it when it begins drying. I hang it on a clothesline out of direct sun and let it dry. You wanna move it around as you do this too so it doesn't dry unevenly on the line either (I think that soaking it and leaving it with only one part up and exposed to air is part of what was giving me the streaking, the last bunch of skeins that I did like this didn't streak at all). I've found it only works on cotton, though I tried Rayon and Bamboo and linen when I first started doing this.

It's not a perfect system and is still in the trial and error stage. My theory is that the water dries out leaving just the soy part imbedded in the fiber, which is the part that has the protein and then the cotton absorbs more like a protein fiber. The color doesn't wash out though with repeated handling and has so far proven fast.