Quick, aside from blueberries, name a food that is naturally blue. Even those blueberries are problematic because they're closer to red when mashed. And thus is the predicament of the scientists at food giant Mars as they struggle to create a naturally blue M&M, writes Malia Wollen in the New York Times. Like a lot of food companies, Mars is phasing out the use of artificial dyes, and this isn't especially tricky for some colors—turmeric for yellow, for example, or beta-carotene for orange. But blue? It's actually "a rarity among plants and animals," writes Wollen. "When it does occur in nature, it often isn’t truly blue, but rather a trick of diffraction, or the scattering of light, which is the case for bird feathers, sky, ice, water and iridescent butterfly wings."
One of the best options is the microscopic algae spirulina, and the FDA approved Mars' petition to use it as a natural blue dye in 2013. The problem? The global supply of the stuff is nowhere near the amount necessary to satisfy demand—"and in any case, sometimes it doesn’t yield just the right blue, or the color degrades and comes out blotchy, or it tastes odd," writes Wollen, who did some tasting herself in the Mars lab kitchen. Other possibilities include red cabbage, various berries, aged red wine, and mushrooms. Click for the full story, which explores the rise of artificial dyes and the science behind the interplay of vision and taste, and offers a snapshot of a "blue-extraction facility" that processes algae from hundreds of manmade ponds in Southern California. (Read more M&Ms stories.)