Learn the science behind:
There are only a few food products that truly make it to worldwide stardom, and Oreo cookies are one of them. You can buy them in so many places around the world, it’s pretty incredible. Why they’re so popular? I wouldn’t know. But, its stark dark black color has to play an important role.
There aren’t many foods blacker than an Oreo. It’s probably as black as thoroughly burned food, though without the unappetizing flavors. The secret lies in just exactly how that chocolate or cocoa, that’s used in an Oreo cookie, has been processed.
Cocoa colors an Oreo black
Upon inspecting the ingredient list of Oreo cookies, you’ll find that the only ingredient that significantly contributes to its color is cocoa powder, of which the cookies contain about 4.5%*. This confirms that they are indeed chocolate cookies. The other ingredients are wheat flour, sugars, fats, leavening agents, salt, emulsifier, and aroma. So there’s no dye, or colorant in there.
However, most cocoa powders are brown, not black. They get this brown color during the production process in which cocoa beans are turned into cocoa powder. But, their exact color depends on the way they’ve been processed. More specifically, on how they’ve been alkalized.
Alkalization turns cocoa powder black
Cocoa powders are made from cocoa beans. At several steps during this process, manufacturers can decide to ‘alkalize’ the cocoa. Normally speaking, cocoa powders are acidic. Their pH-value roughly falls in the range of 4,7-6. During alkalization an alkaline ingredient is added to the cocoa which increases the pH of the cocoa powder, often turning it alkaline.
Increasing the pH, thus alkalizing the powder causs the color to change from a light brown into a dark brown or even black color. Aside from color, it can also make the flavor less bitter and improve the solubility of the powder. That is, it will be easier to dissolve in water, for instance to make chocolate milk.
Process control determines color
The exact color and flavor profile of alkalized chocolate depends on the conditions used to alkalize the chocolate. A different temperature, pressure, duration or alkalizing agent can all result in a different color of cocoa powder. For instance, generally speaking, to make black cocoa powder high temperatures, up to 135°C (275°F) are required to achieve the desired color. Any higher might make it more black, but will also result in undesirable flavors. Alkalizing at lower temperatures will instead result in powders with a red color. Black cocoa powders also take longer to alkalize and generally need higher pressures than brown or red powders.
Dutch cocoa is alkalized cocoa
You may not be able to find alkalized cocoa powder. Instead, you may find Dutch, Dutched, or Dutch-process cocoa powder. These are one and the same. The Dutch naming stems from the inventor of this process who was a Dutch chocolate manufacturer called van Houten. He discovered the effect of alkalizing on cocoa powder over 100 years ago.
Alkalization moderates flavor
Generally speaking, the darker the color, the less astringent and bitter the cocoa powder. As a result, a product made with these darker powder will have less of that typical ‘chocolate’ flavor. It may well be why you may not even associate an Oreo cookie with a chocolate flavored one.
Cocoa powder and processes for its production, Patent WO2013128146A1, link
David Lebovitz, Cocoa Powder FAQ: Dutch-process & natural cocoa powder, 2020, link
Moser, A., Alkalizing cocoa and chocolate, June 2015, The manufacturing confectioner, link
*This percentage was found for Oreo cookies sold in the Netherlands, in 2023, ingredient lists may vary slightly between countries and regions.