Cut the beet into about 1-inch chunks and place it into the cooking pot with enough water to just cover the chunks.
Place the pot on the stove and bring the water to a full boil on high heat.
Reduce the heat to medium and continue cooking the beet chunks until they soften.
Pour only the juice from the pot into a medium bowl.
Crush one of the beet chunks through a mesh strainer into the bowl of juice as a thickening agent for the liquid.
Stir the mixture well and let it cool.
Store the ink in a jar with a tight-fitting lid.
Freeze unused beet ink for later use.