For the ice water method, we harvested fresh indigo leaves (Persicaria tinctoria), immediately stripped the leaves from the stems, and blended them with ice water in a blender until the mixture became a light green, thick, but still pourable pulp. After that, we strained the blended mixture into a clean bucket in which we had prepared ice packs. These homemade ice packs made from biodegradable cornstarch bags filled with water and frozen are useful for keeping the indoxyl-rich water cool, but don’t dilute the solution by melting. Still, it is advisable to work quickly in order to preserve the naturally occurring enzyme called beta-glucose in the liquid. This helps prevent the hydrolysis process, in which the leaves begin to decompose and release the indigo-forming molecule (indican) and enzyme (beta-glucose) from their separate forms. The colours that can be achieved are between turquoise and aqua.