If you are using a food processor, wash, dry, and cut the beets into pieces (no need to peel them first). If you don’t have a food processor, wash, dry, and thinly slice the beets or use a cheese grater to shred them, then set aside.
Place beet chunks into the food processor, and pulse into small pieces.
Place beet pieces (or slices) into the basket of your air fryer. Important: don’t use parchment paper, as it can fly up and burn into the heating element.
Air fry at 170°F (approx. 77°C) for 20 minutes.
Open the basket and mix beet pieces around, then air fry again for another 20 minutes.
Open the basket, mix the pieces around, and continue air frying at 5-10 minute intervals until they are dry. When they are done, their size will have significantly reduced, and they will have a slight brownish color to them.
Place beet pieces into the blender or coffee grinder, and blend until it becomes a powder. Tip: don’t open the top of the blender or grinder right away. Wait until the powder has settled a bit, or else you’ll lose some to the air, your face, and/or your countertop.
Check your beetroot powder and decide if you want a finer powder. If so, continue blending until it reaches your desired texture. The finer the powder, the more effective it is as a dye.
Store the powder in an airtight container in a cool, dark place (like a cabinet or pantry) to maintain its color. If stored properly, it can last several months.