Fructose is sugar derived from fruits and plants. We use fructose to make an indigo vat that does not require lye or chemical reducing agents such as thiourea dioxide or sodium hydrosulfite.
This is a food grade product that looks like fine sugar and is used as a reducing agent, and yes, it is sweet but we don’t recommend using it in your coffee! You will be delighted how simple and easy it is to make an indigo vat using fructose. Other traditional recipes often took a number of days but this is a quick and easy method.
500 grams is enough for several vats. You will also need calcium hydroxide when following Michel Garcia’s recipe.
If you also want to be able to check your vat’s pH, which is useful to know when to add more fructose or calcium hydroxide, pH strips are available here.