12.3.

If you are going to dye indigo the old fashioned way, you will need to collect some urine. Urea comes from the metabolism of protein, not from drinking beer, so if you are drinking heavily to make more water, you have your leg up the wrong tree. Just let it flow naturally; you only need a liter or so and you can collect it in our old friend, that twenty-first century gourd, the 2-liter soft-drink bottle. Be sure to label it or someone may get a bit of a surprise. Put a few blades of grass into it to inoculate it with bacteria and then leave it outside in the sun. The time needed for fermentation to begin depends on the temperature. It will go quicker in the summer than in the winter. Unlike yeasts, bacteria need air so leave the top off your bottle. Your vat is ripe when you can smell ammonia, usually after a few days.

Once ammonia is being produced, grind 1 teaspoon (approximately 1 gram) of indigo in a mortar and pestle with a few teaspoons of water. You want the indigo to be as fine as possible because bacteria have tiny little mouths. Add your ground indigo to the bottle and gently swirl it to distribute the dye without adding too much oxygen. The fermentation will be most active when your bottle is warm so let the little fellows have their day in the sun. The solution will be dark blue when you first add the dye, but it should become pale green once the bugs get going.

If all is well, you should have a pale green vat with a blue scum floating at the surface. If not, there are several things that might have gone wrong. First of all, your vat should smell of ammonia. If not, add 1 teaspoon of household ammonia, swirl to mix it in, and wait another day. Some household ammonia has soap in it; you do not want that kind, you want clear ammonia. Check your vat each day, adding ammonia 1 teaspoon at a time until it smells as it should.

If your vat smells of ammonia but remains blue, then perhaps your bacteria are starving; give them a teaspoon of honey to eat. Fermentation should pick up and the vat should turn green in a couple of days. If not, then either a contamination from your dye or something else has killed your bacteria. Give it a few more days to make sure, but if it does not pull itself together I can only advise you to start over with a fresh bottle.

Once your vat is in order it is time to dye your yarn. Wash your woolen yarn, presumably that which you made in Chapter 6, with plenty of soap and water, rinse the soap out, and place it gently into the vat, trying to add as little oxygen as possible. Use a stick or stirring rod to keep the yarn beneath the surface and let it soak for 10 minutes or so. Then fish it out and gently squeeze the excess fluid from the yarn. In a matter of minutes, the yarn will have changed from pale green to colorfast blue. If you would like the color to be darker, you may re-dip your yarn after 10 minutes in the air; with each dip the color should become darker and darker. Let your yarn air out for a day, wash it in vinegar, and then in soap and water. The color will be quite permanent.

As with a mead, it is possible to keep the vat going by adding food and nutrients. If the vat turns blue and no longer smells of ammonia, you need to add more urine. If it turns blue but smells of ammonia, you need more honey. And if it is pale green and ammoniacal but your blue is getting wimpy, add more indigo.

I realize that not everyone is comfortable handing precious bodily fluids. For you uriphobes, I am pleased to provide an alternative indigo vat which replaces the bacteria with a chemical reducing agent: sodium hydrosulfite. You will learn all about bleach in Chapter 25, but for now all that you must understand is that there are oxidizing bleaches and reducing bleaches and that sodium hydrosulfite is of the latter type. So if I may continue, you should run 100 mL of hot water (50°C, 120°F, no hotter) into a small bottle and add 4 mL of household ammonia to make a kind of faux-pee. Grind 0.2 g of indigo with a little water as before and add it to your vat. Now add 0.4 g of sodium hydrosulfite, which may be purchased as "color remover" wherever dyes are sold. Gently swirl until the hydrosulfite dissolves and let the vat rest. Within 10 minutes or so, the color should change from deep blue to pea green. If not, place your bottle into a pan of hot water as a kind of makeshift double-boiler or bain Marie. Swirl the bottle gently until the color changes from opaque blue to transparent green, as shown in Figure 12-1(L). You may now use this hydrosulfite vat in the same manner as the urine vat for dyeing yarn. The hydrosulfite vat may be "kept going" similarly to the urine vat. If you can no longer smell ammonia, add some. If the vat changes from green to blue, add more sodium hydrosulfite and re-warm it by swirling the bottle in a pan of hot water. And when your blues lose their hues, add more indigo.

Black walnuts produce a wonderful colorfast brown dye without the muss and fuss of the indigo vat. To dye 20 feet of yarn or so, you will need 5 or 6 walnuts freshly fallen from the tree. Now, you are not interested in the nut itself; what you need is the green rind which surrounds the nut. With a knife, peel the rinds from your nuts and place them into a pan or beaker with about 1 liter of water. The good stuff is in the juice from these rinds, so if you can squeeze the juice into the water, so much the better. Now, if you work without gloves you will notice in an hour or two that your hands are stained brown even though the juice was green. You are probably thinking that the colorless juices have been oxidized by the air to produce dark brown, insoluble juglone on your hands. If so, you have indeed cracked a tough nut. This is precisely what we would like to have happen to the wool, but if you do not wish to dye your hands, you had better wear dishwashing gloves.

Heat your rind-water on a stove or hot-plate until it comes to 60°C or 140°F. Any hotter than this may damage the wool. Wash your woolen yarn with soap and water, immerse it in the hot dye-bath and let it soak for half an hour or so. Remove the yarn from the dye and let it air out overnight. It should be dark brown and colorfast the following day. If you would like to dye wool black, dye it first in black walnut and then in indigo.

There is a movement these days to recognize the contributions of women to science. The textile arts have provided an important driving force for the development of chemical industry, as subsequent chapters will show. For now just remember, "It may be the clothes that make the man, but it is often the woman who makes the clothes."

	Quality Assurance
	On the other hand, if your dye washes out with soap and water, you've just been piddling around. Break off a few inches of your colored yarn and tape it into your notebook.