This was possible because the morning after I was so disheartened to be left only with green form I opened my vat to discover a rich blue foam has developed overnight. I still don’t know why it took so long, but I was hopeful that there might be pigment in this batch afterall. I carefully decanted off the waste water and found the blue I hoped for.
I learned a lot this time around. I think that the vinegar really helped in extracting the indigo pigment from the woad plants. In using half the plants, I seem to have twice the pigment. Another thing I observed was that giving extra settling time is well worth the wait. In one careful decanting I was able to pour off most of the waste water. It still took almost a week to fully clean the indigo, but the results were very good this year.