Blue foods! Colorful Cooking without artificial dyes

HomeArticlesBlue foods! Colorful Cooking without artificial dyes

Adding easy blues to your plate

Synthetic food colors-although easily available and simple to use-cause more harm than provision of vibrant colors. Similarly, an increase in number of conscious and more aware consumers has resulted in reduction of usage of artificial food coloring. More and more people are opting for healthier options of food colors. Let us discuss about blues here.

Brilliant blue color is not available easily when compared to other colors for application in natural foods. There are many “blue” foods yet there exist only a few that are proper blue as most contain shades of greens and purples. There are limited options of naturally blue food colors, which is why here we are going to discuss about somewhat blue foods. The blue foods being discussed in this article get their pigments from anthocyanins.

A lot of anthocyanins have unbalanced pigments that are affected by the pH they are exposed to. Red cabbage is the classic example-it can become bright red, purple, blue or dark blue-green depending on the acidity it is exposed to. Many color changing anthocyanins become the blue/purple range in basic conditions and lean toward the purple/red range in acidic ones. Odds are, if you add an acid to anthocyanin-it will turn purple while if you have a purple food and add acid to it, it will turn red. There’s one big catch to the pH color changing process: nearly all foods are acidic. So how are you supposed to cook with blue? Well, there are certain exceptions- foods and preparation methods that introduce minimum acid to keep the hue blue (and inclusion of a pinch of baking soda). There exists a degree of variability of anthocyanin rule that enables you to practice different cooking techniques but still give a little blue.

Blue/purple anthocyanins


Blueberries look blue when plucked, but turn red/purple when are crushed. The pigment in the skin of berries is blue with a neutral pH, but turns red when exposed to the acid present in the pulp of berries. In a pancake batter or muffin mix that contain more base-blueberries may turn green due to exposure to base. To avoid this discoloration, one can either decrease the baking soda/powder in the recipe or add more acid, such as lemon juice or buttermilk.

Blue corn

Blue varieties of corn are packed with anthocyanins. Under acidic conditions, blue corn will appear purple and when placed under basic conditions-it will be bluer. Try substituting blue cornmeal for yellow cornmeal in cornbread or tortillas.

Red cabbage

Red cabbage is the most common natural blue food coloring in the USA. Cooked red cabbage leaves will eventually turn bluish purple if soaked in a basic solution. To make a blue food dye, slice up red cabbage leaves and boil for 10-15 minutes. Strain out the cabbage, reduce the liquid until it is thick and syrupy. The cooking liquid from a whole cabbage will reduce to a quarter of a cup. The residue is intensely purple color in syrup form. By adding only a pinch of baking powder, one can achieve a different shade of blue and if used in large quantities-it can turn the whole batch green. It is important to add sufficient baking soda not only for the color, but also for the flavor. Keep adding baking soda in very small amounts until the color just turns blue. Small amounts of baking soda have a negligible effect on taste. As unappetizing as boiled cabbage and baking soda sounds, the flavor of the dye really is not that prominent. Use it with a light touch to add blue to icings, cake batters and cookies. It is important to note that the color may undergo change. If you add it to an acidic food, it will go right back to purple.

Purple potatoes

Purple potatoes produce a vibrant purple when raw, but when cooked-the balance turns to a brilliant blue-purple. This color change is of a different nature when compared to other acid/base changes. Cooked purple potatoes are prone to color changes due to acid, but lesser than red cabbage or blueberries. When exposed to high concentrations of acid, purple potatoes bleach and turn a very light purple and are not like the intense purple of raw potatoes. Purple potatoes are also less likely to bleed their colors out. All these factors enable them to add some unusual color to a plate, without causing trouble with regards to the pH. Packed with anthocyanins, purple potatoes are more nutritional than white and yellow potatoes.


Cornflowers are also known as bachelor’s buttons informally. These are naturally bright blue. The blossoms are edible, and can be added fresh to salads or as a garnish for a dessert plate. The flavor is very mild and grassy and are used for color purposes only. Some loose leaf tea blends include cornflowers that make a striking display in contrast to the shriveled black tendrils of tea leaves. It is important to make sure that the supplier can verify that the flowers have been grown organically or treated only with food-safe chemicals.


Often grown nearby tomatoes and eggplant, the borage plant produces big hairy leaves and clusters of little five-pointed blue flowers. Borage is a blue-flowering Italian herb. According to some folk medicine traditions, borage flowers are supposed to elevate your mood. Like cornflowers, adding fresh borage flowers to salads or as a garnish to desserts is also a popular application.

Butterfly blue pea

The most spectacular of the blue anthocyanins is the butterfly blue pea flower. This pea vine produces beautiful and intense blue flowers.

Use of this blossom is dominant in Thai, Malaysian, Burmese and Chinese cooking traditions. Pulut tai tai, a Malaysian sticky rice cake seasoned with coconut and pandan, is traditionally speckled blue from pea flowers. The intricately shaped Thai dumpling, chor ladda, resembles a bright blue flower. The flowers are also used in Thailand to make a chilled herbal tea, which is considered refreshing and cooling. The flowers can be dried or used fresh, to make an incredibly vibrant blue infusion. The flavor of dried butterfly blue pea flowers is mild and herbal with a hint of cucumber. The bright, electric hue of these blue flowers will turn bright purple in the presence of acids.

Other blue pigments

Bluefoot and blewit mushrooms

These really look a slightly more purple than blue but they are called blue and look incredible. They have a unique and distinct flavor. Blewit Mushrooms are quite popular in USA. These are more uniformly blue/purple when compared to bluefoots as these are blue only at base. Bluefoot mushrooms have a rich flavor that also seem woody and meaty. As with all flavorful mushrooms-the flavor spreads beatifully when cooked with cream.

Blue cheese

The blue cheese gets its blue color from processing of cheese which contains addition of mold culture and not from anthocyanins.
All kinds of Mold belong to the Penicillium category and differ based on the type of blue cheese. The blue color is slightly dark and does not bleed. While serving cold dishes with blue cheese, one can use a string to cut the blue cheese into thin sheets- the spots on surface can be fairly striking and more interesting than crumbles.

Pickled garlic

When raw garlic is pickled, small quantity of sulfur can react with trace amounts of copper from water or cooking implements. This results in garlic looking normal initially but, a few weeks later it turns blue/green. If you don’t want your garlic to turn blue, one needs to boil it for a short while before placing it in the brine. The blue achieved is not an anthocyanin, but trace amounts of copper sulfate. While the amount in pickled garlic is harmless, in larger quantities copper sulfate is toxic.

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