Wash the turmeric rhizomes. No need to peel or boil them first.
Cut the turmeric rhizomes into thin slices, aiming for about 1/8" thick and fairly consistent slices.
Lay out the turmeric slices in a single layer on your food dehydrator racks (or on a baking sheet, if drying in the oven).
Dry the turmeric in a food dehydrator at 100-110°F, or in the oven on the lowest heat setting possible.
The time it takes for them to fully dry will vary depending on your individual machine and the thickness of the slices, which may be several hours to a couple of days.
Dehydrate the turmeric until the pieces are completely dry. When done drying they will easily crack and snap in half, rather than bending.
Use a blender, food processor, or coffee grinder to churn the dried turmeric into powder.
Pour the turmeric powder through a fine mesh strainer poised over a bowl and sift it. Take the collected leftover hard bits and run them back through the Vitamix/blender another time to pulverize them into powder.
Store the finished turmeric powder in a glass air-tight container, such as in a mason jar with tight-fitting lid.
Keep the container in a dry, cool place - such as the pantry. When properly dried and stored, your homemade turmeric powder should last for over a year.
Enjoy homemade turmeric powder with a variety of meals - but be sure to add black pepper and/or a healthy fat along with it to increase bioavailability and get the most benefit from!