Pinkish to Red
1/4C cooked diced beets + 1t beet juice (from the cooking water)
Food Color: Blend the beets and juice together until smooth and strain. Place the liquid in an airtight jar, in the fridge, and it keeps ~6 weeks. Icing, frosting, batter: Just add 1t to the dish and mix in to get a pink color. If more is required add another teaspoon. Remember it is easy to add more, but impossible to remove if you have used too much. Caution: I use paper towels to clean up after working with red beets and wash my hands very quickly to remove the color. It does wear off after a while though.
Other choices: Mainly pomegranate juice comes to mind. However, keep in mind it will have a flavor. When I cook braised red cabbage I sometimes add red wine vinegar to help keep the redish color from fading.
Yellow + Orange
1/4 cup water + 1/2t ground turmeric
Food Color: Heat the water and turmeric until small bubbles show, ~3min. Remove from heat and cool then store in an airtight jar, in the fridge, and it keeps ~6 weeks. Icing, frosting, batter: Just add 1t of the food color liquid to the dish and mix in to get a yellow color. If more is required add another teaspoon, remember it is easy to add more but impossible to remove if you have used too much. Caution: Can stain and hard to get out of things. Again, I use paper towels and clean up messes right away.
Other choices: For cooking I just add 1/8t to 1/4t into a dish to see it change into a brighter yellowish color. Other possibilities include the juice from yellow beets, mangoes, carrot juice (orange), paprika, and saffron. If using saffron, be careful that it does not overpower other flavors in your dish. I use saffron in my Spanish Egg Bites.
Purple + Blue
Purple-blue: 1/4C blueberries + 2 teaspoons water
Food Color: Blend the berries and water together until smooth and strain. Place the liquid in an airtight jar, in the fridge, and it keeps ~2 weeks. Icing, frosting, batter: Just add 1t to the dish and mix in to get a purple color. If more is required add another teaspoon, remember it is easy to add more but impossible to remove if you have used too much.
Blue: Red 1/2C shredded red cabbage + 1/4C water + 1/2t baking soda
Food Color: Wash and chop red cabbage and cook with water ~10 minutes. This process will leave you with a purple liquid. Bright Blue: Add ½t increments of baking soda to the red cabbage liquid until it turns a bright blue. Use as little as possible for the soda will change the flavor of the mixture.
Other choices : Purple sweet potatoes and purple carrots.
Green
1C spinach + 3T water
Food Color: Put whole spinach in water and boil ~5 minutes. Blend the water and spinach until smooth (if it gets clumpy add some more water in 1T doses). Strain the mixture and put the liquid into an airtight jar, in fridge, and it keeps ~6 weeks. Icing, frosting, batter: Just add 1t to the dish and mix in to get a green color. If more is required add another teaspoon, remember it is easy to add more but impossible to remove if you have used too much.
Other choices: Using liquid chlorophyll, Matcha powder, spirulina powder, wheat grass juice, and parsley juice.
Brown
Options: Espresso, cocoa powder , cinnamon, instant coffee granules, and very dark black tea.
Black
Options: Squid liquid, activated charcoal, black cocoa powder.
Comments
Caution: I am not a baker so cannot guarantee these colors last through the baking process. I only know what I cook with, and that the colors work in cooking.
I try to avoid foods that have artificial dyes, i.e., most processed, prepackaged, and food mixes. I read the labels looking for the food dyes and will not purchase them if they are there. Any foods that are USDA certified as organic cannot have artificial dyes.
Natural dyes can introduce their flavors into a dish so use as little as you need and consider that when cooking. The natural dyes are more vibrant if you use them sooner, like right after you make them. In addition to storing in the fridge, you can freeze them in an ice cube tray and they may last longer in the freezer. Just remember that strongly colored foods are generally stronger flavored as well.
Sources: Lots of these ideas came from other websites, but I have tested them to make sure they work. Some are very obvious if you have worked with the foods (turmeric and beets for example). Here are some of my sources: Leites Culinaria, fix.come and Bolder Baking.