Thursday, 25 November 2010

Stinking Indigo Vat at my Door

It was time to get rid of the old liquid and clean up the ceramic vat and the blue stained walls around it. For the past three years indigo pigment and slaked lime and hydro sulphate were added as necessary week after week. These eventually build up at the bottom of the vat. Eventually it starts to reek something fierce. It dyes as usual but the fun is gone with your gag reflex on hair-trigger mode.

But the strong ammonia smell of a fermentation indigo vat just smells like tough love perfection. However, it is impossible and impractical to keep a fermentation vat going throughout the year. Too much constant maintenance, way too expensive, and the vat is mostly used by students and friends and they tend to dump in anything for the thrill of watching it turn blue.. You have to be very gentle dying with a fermentation vat and it is impossible to keep an eye on who is dying what. A good friend once dyed a heavy duty hammock he picked up in Thailand in the best fermanatation indigo. Must have been a good $200 indigo dye job on a $5 hammock.

Now I make a fementation vat once a year using my own home grown indigo if there is some very good stuff needing a dye job.

The buildup sludge of exhausted pigment, slaked lime and hydro sulphate at the bottom of the vat. I dyed a full day to use up as much pigment as possible. I threw in some old sheets to absorb as much hydro sulphate as possible and neutralize the pH. These I dried in the sun and then put them out in regular burnable garbage. Then I siphoned off the dye liquid. How to get rid of this muck at the bottom is the problem. I dribbled in water for one night and let it go down the outside drain that goes into a river nearby. It would be like dumping in a bucket of bleach if I did it directly so I prolonged the process. It didn't really work and the muck was still in the bucket in the morning. I spread it out to dry and them I'll put it out in the burnable garbage. The exhausted hydro sulphate being the bad guy here.

A fermentation vat is easier on my conscience to throw away. The shock is the high alkaline and that can be soved with the dribble technique.

This little creek crab seemed to like the blue water. It was horrifying and I got him out of there and washed up and placed upstream in a flash.

Add enough slaked lime to get a pH reading of 12. Do this before you add indigo pigment so that the pH test paper doesn't dye blue. The orange paper is a more specific pH test paper used for a more accurate reading. German made electric pH readers are not so expensive and very easy to use for people not used to keeping an indigo vat.

Next add the indigo pigment itself. I use Konya brand I purchase from Seiwa. It is expensive but very very high quality.

A fresh indigo vat ready to use on a misty autumn afternoon.


  1. I did a fermentation vat once with some sukumo I picked up in Tokushima, and I can distinctly recall the foul stench that wafted in the air post-dying. It sat on our balcony for almost a whole year before I tossed the remains. Needless to say it was putrid. Beautiful color though. haha

  2. Another lovely post. I like so much your emphasis on process: the tools and the details as well as outcomes.

    I'm often reminded when I read your blog of what little I've read of the world of Edo carpentry. A similar pride in process - to the extent that I believe that Japanese carpenters traditionally once a year place their worktools in in the toko-no-ma.

    A pleasure to read, with wonderful visual accompaniments (yum! particularly that concluding photo).

  3. i had a very fermented, old black walnut "vat" that i dyed my friend's wool socks in. they stunk. he threw them out before i told him i could try rinsing them in something to remove the smell.

  4. excuse me, can i have a link to purchase ko nya siewa indigo dye?