Oreo cookie

What Makes Oreo Cookies Black?

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.

Hydrox (left) vs. Oreo (right)
Black and white, it’s what sets Oreos apart. There’s only one cookie like it, it’s lesser known ‘cousin’ the Hydrox cookie.

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.

three different types of cookies with different cocoa powders
Here we baked a simple chocolate cookie with about 7% cocoa powder in the recipe. Each batch was made with a different cocoa powder. Notice the stark differences in color. This is how you can achieve black cookies.

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.

six differently processed cocoa powders
Six different cocoa powders, each processed in a slightly different way. Notice the impact of pH-values on colors. The powders with a pH-value <6 are natural and have not been alkalized.


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.

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  1. I think the oreo wafers are dark brown and its sparked a debate. I understand it is a very dark color but don’t you see really really really dark brown too???

    • Hi Felicity,

      You’re question made me have a thorough look at Oreo cookies again and I guess you could both say they’re black as well as super dark brown. So, if you see them under artificial lighting they look pretty black to me. But in sunlight they do look very very dark brown, especially when I compared them to Hydrox cookies (almost the same as Oreo’s, but different brand), compared to those Oreo’s actually look a little brownish :-).
      The reason behind them being so super dark stays the same though :-)!

  2. I recently read with great interest (shock) that Hydrox cookies were the original creme-filled chocolate sandwich cookie and that Oreo’s were the “knock-offs”. As a child of the 60’s, ever loyal to my beloved Oreos, I had believed otherwise. My child’s mind thought that those “icky” Hydrox were cheap imitation ‘rip-offs’of my sacred Oreos bought only by low-class people too cheap to buy the real thing—well I have been enlighten.
    The main reason I am writing is to share an insight to the reason that “Hydrox” may have been so named that goes against the general wisdom I have read in various articles on the Internet.
    I was recently sharing the history of the Hydrox vs. Oreo with a friend from Germany who has suddenly discovered Oreos as they are relatively new in Germany. I was telling him the sorted story of how NABISCO out competed the original Hydrox with their copy. He commented that “Hydrox” was a really ugly name for a cookie and I told him that was my impression as well and the opinion of many others and that it has been speculated that the unappetizing name may have played a roll in the popular cookie’s downfall.
    I have read a lot of explanations of why the cookie was named “Hydrox” in the first place and mostly what is said is that this “Age of science, chemical sounding name” was intended to make people think of something modern, pure and clean like water. This explanation just didn’t ring true to me…
    I read some descriptions of how Hydrox and Oreo’s are made and what makes the chocolate cookie part so dark. Again and again there was a reference to “Dutch cocoa” and a process that uses an Alkaline substance to alter the cocoa. I was explaining this to my German friend who is a physician. Suddenly he said: “Many of the alkaline substances that are/could be used are: Sodium Hydroxide, Potassium Hydroxide, [Whatever] Hydroxide, etc. could that be the reason they are called ‘Hydrox’ “. Suddenly a ‘Eureka’ moment!
    I want here to declare to be the first person [I know of] to put forward the possibility that the name “Hydrox” comes from the alkalized cocoa process used in their creation.
    Please let me know what you think of my hypothesis. Thank you.

    • Hi Chris, That’s a great thought and to me it sounds like it makes a lot of sense. I guess at the time they did indeed think Hydrox sounded fancy, even though we don’t think so anymore, and it could well be true that it originated from a scientist at the company who came up with the name based on the alkalization process. Thank you for sharing!

  3. To add one more thought: There could be colouring added, although it is not on the ingredients list. Sometimes companies add burned sugar (very dark black) to a recipe. That could still be very true for Oreo cookies.

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