Natural Food Coloring

For a brown color, use a little browned flour, a little burnt sugar, or caramel. Pounded, uncooked spinach leaves make a rich green. Adding some spinach leaf puree makes a lovely deeper green. This green can also be used to tint icings, desserts, ect. Another way to make a cooked spinach green coloring is by washing some spinach, boiling it until tender, and pouring off the juice for your coloring extract. For a stronger green, let the spinach cool, sqeeze dry, mash by pounding, and then put through a sieve. Cooked green peas make a lighter shade of green; slit pea soup makes a very pale green color. The coral of a lobster pounded and put through a sieve yields red, as does vinegar or water that has stood on sliced boiled beets.
-Carla Emery The Encyclopedia of Country Living