This week: Getting that indigo vat to work
Every week, we are emailed with questions from our natural dye community asking simple and complex questions that we thought might be worth sharing. Of course, all of your burning questions are answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors.
I was hoping you might be able to help me with this indigo vat that is making me want to jump off a cliff. I really don’t know why indigo and I don’t seem to get along. I seriously admire the patience you have for natural dyes. Anyway, I’m trying to make a 1-2-3 vat and I really don’t know what I’m doing wrong. My initial mixture will not separate. It’s not fermenting and getting its flower on top and it’s not separating. Any suggestions for what to do?
If the indigo vat is dark blue and not separating into a distinct sediment layer, it probably needs more fructose. You need to use fructose and not sucrose (table sugar) or glucose as those other sugars will not work. Add a couple of heaping spoonfuls to your jar of stock and stir well. You should see a flower start to form, and it may be just a cluster of tiny bubbles. If no flower after about an hour, then add a small amount of calcium hydroxide and stir well and let it settle. Add a little more of both calcium hydroxide and fructose if still nothing happens. Once you have a metallic skin on the top of the jar (even if there is no flower), you can proceed to making a vat.
Because it sounds like your stock is a little temperamental, make a vat with very hot water – like 90C – and fill your bucket about 2/3 full. Carefully stir and add all your stock, then let it settle and cool down to about 30C, which may take overnight. Cover it with a lid while it’s cooling down.
The next day (or when it’s 30C), carefully remove the lid and take a spoonful of the stock without stirring. It should be amber brown and clear. It can also be greenish yellow, depending on the amount of indigo you used initially. If it is one of these colors, and clear (not murky blue-green or green), then you can proceed with dipping. If it’s still dark blue and murky, add more fructose, stir and let it reduce and clear.
I’ve had vats where I’ve added cups of fructose to finally get it to reduce, so just keep adjusting, stirring and letting the chemistry do its thing.