The leaves may then be crushed and the larger sticks removed to facilitate extraction. The remaining material should be placed in boiling water and boiled for at least about two minutes and up to about thirty minutes in a sealed container with agitation as needed. Longer boiling time is acceptable but will not extract a substantial amount of material. After the boiling process is complete, the container should be immediately withdrawn from the heating source, kept covered, and stored at room temperature for from about 1 hour to about 12 hours. This may be accompanied with occasional agitation; the longer the mixture is stored, the less agitation may be needed. The extract should then be filtered, and excess liquid removed from the material. The resulting extract constitutes a concentration of approximately 30mg/ml Cotinus coggygria extract. In order to prepare more concentrated material, the extract should be further concentrated by reducing the volume to between about two and about five times its original yield to produce between a 60mg/ml and a 150mg/ml extract. This process should be achieved by heating and evaporating the material on a stirrer plate at a most preferred temperature of between about 800C and about 85°C. The extract may then be stored at 40C without losing activity.
