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It’s been exciting to see the progress in getting the Theobroma cacao genome sequenced and off to the databases.

But….

I’ve toured the Theo chocolate factory twice now, and there’s a crucial piece in the story that appears to be missing.

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photo by S. Porter 2010


You see, chocolate is like wine. We don’t get the chocolate we love from eating the fruit. We get the so-called “food of the gods” by eating the fruit after it’s been fermented. And, just like wine, microorganisms are the ones doing the fermenting.

I learned this from attending two separate tours at Theo chocolates, our local chocolate factory. One tour was sponsored by the Puget Sound chapter of the American Chemical Society. The other was just a Saturday morning in the summer. Both were delicious.

Before the tours, I was a virgin in the world of chocolate. Now, I’m a snob.

Apparently, some of the most important steps in making good chocolate happen long before the beans arrive at the factory door. Before chocolate beans travel to the US, the fruit from the Cacao plant needs to ferment. This step happens on the farm. Cacao fruit are put in funny-looking boxes and bacteria break down substances in the beans.

To really know about making good chocolate, we need to know who works on the fermentation. We need to know about the bacteria and yeast that participate in this most important step. Fermenting cacao is a sweet area and ripe for a good metagenomics sequencing project.

We do know the bacteria in the fermentation mix are important because they produce the volatile compounds and polyphenols that give chocolate it’s flavor and antioxidant properties. That’s right, if chocolate is properly treated, it has antioxidants and is healthy. The metagenome is also important for the “terre noire,” a phrase that I think means something like “taste of the place.” [correction from Vicki – the word is “terroir”]

When I toured Theo Chocolate with the chemists, we were treated to a lecture by Andy McShea, the chemist at Theo. Theo has done interesting work measuring the volatile compounds from different chocolate beans and characterizing the distinctive profiles from each type of bean. Apparently, if the fermentation goes bad, the beans will never be good.

I liked that. Chocolate factories make better chocolate by doing good science.

Comments

  1. #1 theshortearedowl
    September 23, 2010

    There’s a breakdown of the microbial succession involved here: http://www.smccd.net/accounts/case/chocolate.html

    I’m assuming that they are naturally recruited, ie. they leave the beans out and the microbes just turn up. It would be interesting if anyone has tried customising the blend – you’d have to use a sterile environment to do it rigorously though, which would be expensive for mass production.

  2. #2 Sandra Porter
    September 23, 2010

    Thanks for the link @theshortearedowl!

    Some fermentation happens when the fruit are on the ground, but most of it takes place in the same white boxes, year after year. I imagine the boxes contain an interesting population of microbes.

    Chris Case has a nice description of the succession at the site you mentioned, but those data were obtained from microbes that could be cultured. Now that we can identify microbes through sequencing, we know there’s more to the ecosystem than meets the eye.

  3. #3 Vicki
    September 23, 2010

    I think that may be “terroir.” (“Terre noir” ought to mean “black earth,” which to me suggests good soil with plenty of humus in it.)

  4. #4 Sandra Porter
    September 23, 2010

    Thanks Vicki!

    That probably explains why I couldn’t find the word with Google. I’m not that good at taking notes on my phone and jotted it down wrong.

  5. #5 Calli Arcale
    September 23, 2010

    You see, chocolate is like wine. We don’t get the chocolate we love from eating the fruit. We get the so-called “food of the gods” by eating the fruit after it’s been fermented. And, just like wine, microorganisms are the ones doing the fermenting.

    While this is very true, it shouldn’t discount the value of understanding the cacao bean itself. A Merlot grape will produce a different wine than a Pinot Noir grape, even if grown in identical soil in identical weather and fermeted with identical yeast in identical conditions. Every piece is important — and adding the bacteria still doesn’t list all of the important pieces. I don’t know how sensitive cacao is to weather or terrain; in the case of wine, those make a huge difference — sometimes the difference between a fine wine and a nasty mouthwash. I’m sure Theo and other producers take all that into account; chocolate is very big business, and even a slight margin over a competitor in one area can bring strong returns.

    It’ll be cool to see what they can get out of the gene sequence. I’m not real optimistic of improving the flavor, but if they can make the trees hardier without compromising flavor, that would be good.

  6. #6 Sandra Porter
    September 23, 2010

    I agree Calli. We need both.

  7. #7 jj
    September 23, 2010

    I’m assuming that they are naturally recruited, ie. they leave the beans out and the microbes just turn up. It would be interesting if anyone has tried customising the blend – you’d have to use a sterile environment to do it rigorously though, which would be expensive for mass production.

    That’s not a crazy idea in the least, and would not be too expensive if you already have the labs in place. This is how 99% of all beer brewing is done (and much of wine); using lab grown cultures of yeast (and in some instances of Belgian and sour brews, bacteria)that are said to be almost 100% the strain(s) advertised. There are two major producers of ‘liquid’, White Labs, and Wyeast (both have websites, not going to spam with links). Dry yeast is ‘said’ to be more likely to be containerized by wild yeast strains.

  8. #8 bioinformatics training chandigarh
    September 24, 2010

    Hey…. thanx for this interesting information about making good chocolate and thanx to bacteria also which ferment s the beans and give them their flavor and color

  9. #9 Bryn Kirk
    September 24, 2010

    Thank you for this great post and the link to the succession article. I really enjoyed The Microbiology of Chocolate by Chirstine Case, it was excellent. I have tasted chocolate liquor made from beans that were fermented 3 days, 4 days and 5 days and over 5 days. Big difference. The flavors that are unlocked during fermentation can be subtle but combine that with the way the bitterness and acidity gets manipulated, you do notice it in the end product.

    Bryn

  10. #10 Tsu Dho Nimh
    September 24, 2010

    Some fermentation happens when the fruit are on the ground, but most of it takes place in the same white boxes, year after year. I imagine the boxes contain an interesting population of microbes.

    When Kikkoman opened a soy sauce plant in the USA, they couldn’t get the stuff to taste right until they brought over some of the moldy-oldy vats and processing equipment with their centuries of accumulated mutations.

    Differences in chocolate flavor would be influenced by the local microbial population, just like beer with its yeast strains.

    Nice old fermentation boxes with generations of specialized bacteria (yum!).

  11. #11 Lifewish
    September 26, 2010

    That’s right, if chocolate is properly treated, it has antioxidants and is healthy.

    I thought the “antioxidants = healthy” thing had been mostly debunked?

  12. #12 Sandra Porter
    September 26, 2010

    @Lifewish:

    I wrote:

    if chocolate is properly treated, it has antioxidants and is healthy.

    I didn’t write that antioxidants make chocolate healthy, just that chocolate is healthy AND contains antioxidants.

  13. #13 lisbeth jardine
    September 29, 2010

    Several hours since I read your blog, which I enjoyed v. much, and yet . . . I can’t help but tell you how fatal was that error re: “terroir” [vs. terre noire–at least you spelled those words correctly]. It’s like the French whisk a boy picked up in my local Albertson’s a few weeks ago and was asking his maman, “what is?”, and she didn’t know, and the passing grocery clerk did not know, and so I stepped in and said what it was, and the next questions was, “So, what’s it for?” [At least that Q. came] And I explained. [And at least the boy knew what a souffle is, but neither the check-out clerk nor the store manager for the day knew what a French whisk nor what a souffle is.]

    Do you catch my drift? By the way, my birthday (born in Seattle) is Oct. 18, 1946. Mostly, I’m surprised Albertsons’ carries a double-French whisk for $5.99. I tried to explain how it does what a $300 Sunbeam (and even more costly) set does — and doesn’t even use electricity.

    My poor late mamman, a graduate of Whitman College, I just know she’d spin in her grave to hear that there’s such a thing as a Walla Walla oeniferous terroir. In 1942, she taught her 1st year of professional h.s. teaching at Moclips, out on the far wild coast.

    Lisbeth Jardine
    Port Angeles, WA

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