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Food Science

Periodic graphics: chocolate chemistry

Chemical educator and Compound Interest blogger Andy Brunning takes a peek inside the delectable molecular world of chocolate

by Andy Brunning
March 14, 2016 | APPEARED IN VOLUME 94, ISSUE 11


To download a pdf of this article, visit

A collaboration between C&EN and Andy Brunning, author of the popular graphics blog Compound Interest ( To see all of C&EN’s Periodic Graphics, visit


This article has been translated into Spanish by and can be found here.



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Jim Parsons (March 15, 2016 4:34 PM)
Now that is some real flavor chemistry!
keith gargus (March 20, 2016 2:00 PM)
I live in Nicaragua, and like dark chocolate. There is a small chocolate maker in the neighboring city (matagalpa) that makes it from a to z. They grow their own, roast it, etc. The last time I ate some, I looked at the ingredients label: Chocolate, cane sugar. Doubt many of the designer chocolates can brag of such a spare list.
theorist (December 30, 2016 3:42 PM)
That's not a virtue. By doing that they're not telling you what set of ingredients were combined with the cocoa beans to make the chocolate.
Debbie McDaniel (March 20, 2016 5:55 PM)
Does this chart mean that the good feeling effect only comes from dark chocolate?
Andy Brunning (March 22, 2016 4:23 AM)
The compounds identified under dark chocolate are also present in any chocolate that contains cocoa solids - so milk chocolate would contain them too, albeit in slightly smaller amounts due to the lower cocoa solids percentage.

There's actually some debate over which compounds, if any, might be responsible for the 'feel-good effect'. The compound identified here, phenethylamine, has been implicated, but others have claimed that it's rapidly metabolised before reaching the brain. Anandamide is another compound that's been linked with a possible role in the effect.
AnnieLaurie Burke (March 20, 2016 11:37 PM)
White "chocolate" is NOT chocolate. If vegan "mayonnaise" results in lawsuits because it doesnot fit the traditional recipe for mayonnaise, someone ought to sue the companies calling this artificial junk "chocolate". Disclosure/disclaimer: I am NOT a vegan. Calling this bit of manufactured glop "chocolate" is a marketing ploy to sell you junk food and make you think you are getting something that tastes good and has health benefits. It succeeds at neither goal. Chemical engineers know better.
New Wayfarer (July 8, 2016 12:00 AM)
Honestly I enjoy the taste and texture of what is called white chocolate. I understand if you personally don't like it, but I don't understand your passionate blanket claim that it doesn't appeal to anyone. If that was the case, it's production would of ended years ago. It's no harm to enjoy in minor amounts, and I'd hope you would not judge those of us who do.
Nathan (March 21, 2016 10:13 AM)
I am wondering why theobromine is toxic specifically to dogs??
Suzanne (March 21, 2016 11:31 AM)
Theobromine is not specifically toxic to dogs. Theobromine is toxic to all animals, including humans. Domestic animals such as dogs do not metabolize theobromine as quickly as humans. LD50(mg/kg): Humans-~1000, Dog-300, Cat-200
Cami❤️ (February 12, 2017 10:36 PM)
Theobromine is a very toxic alkaloid to dogs , kind of like a stimulant , like caffeine is to us humans. But dogs do not have a specific enzyme to break down theobromine , humans do have such enzyme to help breakdown the theobromine. If a dog ends up getting a hold of the chocolate, since their body can't break down the theobromine, they could overstimulate the nervous and cardiovascular symptoms in a dog. That just increases the risk of vomiting, high blood pressure, dehydration, and even abdominal pains. These symptoms depend on how big the dog is and what type of chocolate the dog has eaten. Darker chocolates include higher percentage of theobromine in it. The bigger the dog can take more theobromine in its body. The smaller the dog, the smaller amount of theobromine the dogs body can contain.
Joseph (March 28, 2016 12:49 PM)
I do not wish to comment on the article, though I found it very informative. Instead, I wish to comment on your comment process. THANK YOU THANK YOU THANK YOU. I admire how you are honest about the expectations of the commenter, the guidelines are clear. And I love how you moderate the postings. So many web publishing organizations should be forced to do the same thing. Maybe then we would stop hiding behind the digital wall and stop sniping people with unnecessary comments referring to others as stupid, idiots, and whatever other labels and rude language people use when they seem to lack the intellectual capacity to make a sound argument without resorting to name calling. Again, THANK YOU THANK YOU THANK YOU.
Douglas Furtek (March 31, 2016 3:19 AM)
Here is the story I heard about butyric acid in milk chocolate: In the olden days when transporting fresh milk to Chocolate Company X (name withheld) was not too reliable, milk would sometimes spoil, but was used anyways to make milk chocolate. Then when milk transport and refrigeration improved, there was much less butyric acid in milk chocolate. The public had become accustomed to the slightly rancid flavor note, however, and preferred the old-style chocolate. So Chocolate Company X then deliberately added butyric acid to their milk chocolate. I must admit, I like the rancid flavor note!
Christine English (August 16, 2016 12:32 PM)
Nice. :)
Jan Glinski (April 1, 2016 5:57 PM)
I wonder, why the major ingredients such as antioxidant Procyanidins (tannins) have been omitted? Perhaps also resveratrol.
There is a good science attributing Procyanidins with amelioration of several diseases and improving cardiovascular parameters.
Andy Brunning (April 4, 2016 10:20 AM)
Simply the case that there isn't enough space in these graphics to include all the compounds – there's always the possibility of including them in future posts on the CI site, however.
BabyBoomer Writer (September 19, 2016 2:51 PM)
I am a consumer, not a chemist or engineer…
Recently, I purchased a treat at the local grocery store. I believed I was buying dark chocolate-covered cranberries. But here's what the label said:

Dark chocolate (sugar, chocolate liquor, cocoa butter, chocolate liquor processed with alkali, soy lecithin [emulsifier], salt, vanilla) dried cranberries (cranberries, sugar, sunflower oil) confectioners’ glaze.

How did a healthy snack become a chemical feast? Is chocolate liquor chemically a fair substitute for Dark Chocolate as the label states?
Dalya Sanders (September 26, 2016 11:27 PM)
It is very interesting to be able to see the the chemical breakdown of one of the most-liked candies around. I have always heard from my elders that dark chocolate is the best to eat due to it being more pure, but actually seeing the breakdown helped to prove this to me.
Mackinzie Claiborne (September 29, 2016 11:09 PM)
Learned much on the breakdown of chocolate it was very interesting to learn about.
Ashley Brown (October 14, 2016 11:48 AM)

Learned about chocolate and how its broken down

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