Yesterday and today were very lab intense days, and went until about 6pm. (I’m making the tired excuse for not having a day two post up yet.) Here are the notes from yesterday:
* Spent some more time with Wendy and Gerardo, my lab partners. Wendy is a chocolatier from Napa who started studying chocolate in Paris after deciding that teaching English was getting boring. She has the uncanny ability to watch something done once, and repeat the process right way. She picked up the spreading/gathering motion required for hand tempering very quickly, while my initial attempts just drew a lot of worried looks from the instructor. Gerardo is the one person in class that is also interested in the bean-to-bar process, but mainly from the perspective of reproducing Oaxacan drinking chocolate. He’s spent time in remote villages learning the secrets of Mexican chocolate (which contains little sugar, is made with almonds and chiles, and apparently contains the bean husks.) I tend to love drinking Ibarra chocolate, and Gerardo says that the Oaxacan stuff is much tastier.
* Today’s lectures were Terry Richardson (the English Yoda of chocolate) speaking on tempering, and Ed Seguin (VP of R&D for Guittard) taking about bloom. Non chocolate geeks might not be familar with these core concepts, so I’ll wax pedantic here for a second. Tempering is the process (in any material) of getting the right crystalline structure built. Steel is tempered, and so is chocolate! Much more on this topic in a bit. Bloom is what happens when you abuse chocolate. The most important material fact about chocolate is that it is solid sugar and cocoa particles embedded in a matrix of solid and liquid fats. Most chocolate (in apparently solid form) contains liquid fat, and some crystallized fat that holds it all together. Tempering builds good crystalline structures, and if you get chocolate too hot, or let non-cocoa fats mix into the chocolate, the liquid fats escape to the surface, and create ugly white streaks. The chocolate also goes from a snappy solid that melts just below body temperature to a multi-crystalline mess that feels wrong when you eat it. This is a huge concern for anyone making chocolate. Apparently, chocolate manufacturers and candy makers like to argue and sue each other over who’s at fault when a huge batch of chocolates blooms and is spoiled.
* Tempering notes. So, chocolate is particles embedded in a fat matrix. Inconveniently enough, cocoa butter can form six different types of crystals, and we really only want one in the chocolate: Type V. It forms chocolate that’s stable at room temperature, can be handled without melting, has great mouthfeel, and contracts when it cools. This contraction allows the chocolate to be molded. The only way to get this composition is to manipulate crystal formation and melting. The different crystal types melt at: 63F, 74F, 78F, 82F, 93F, and 97F. Tempering creates type V heavy chocolate by first taking the chocolate up to 125F or so, which melts all the crystals. You then have to chill the chocolate down to about 80F, which allows the formation of IV and V. You create seed crystals by agitating this chocolate, mixing the seeds in, then slowly taking the chocolate up to 90-92F. At the same time, if you want really good, shiny chocolates, you need to do this in a way that moves quickly enough that you get a lot of small crystals rather than a few big ones. How hard could this be? 🙂
* Tempering lab. We got to mess with three or four ways of performing this operation. If you are Hersheys, and have to make several thousand pounds of Kisses a minute (like one of the people in class), you have big expensive machines that do this. However, they still need lots of care and feeding, because you are dealing with tricky time and temperature issues on an agricultural product that’s never completely consistent. The hand methods involve using a double boiler with a water bath to move the chocolate temperature. The “mush” method creates seed crystals by spreading and scooping chocolate on a cool marble slab. What makes this process maddeningly difficult is that these changes are all largely invisible in liquid chocolate. When chocolate crystallizes, it just loses a tiny bit of sheen. This, and small changes in viscosity are the only ways to tell if the process is working. There is a tempermeter which can tell how crystallized chocolate is, which I got to operate on Wednesday.
* The majority of the lab time was spent hunched over a double boiler, looking in vain for any clue that crystallization was happening correctly. I got to temper a mix of cocoa butter and butter oil (which, with some sugar and milk powder would be white chocolate), which revealed the crystals in the mixture as it was tempered. We then tempered dark chocolate that we made yesterday, coated some peppermint candies and made a happy little chocolate bunny. I now know the dark secret of how you cast a hollow chocolate rabbit!
* Bloom lecture. Bloom is the chocolatier’s nightmare. Once you have spent all this effort putting the chocolate into this precise crystalline form, it can be knocked out of that form an into a moldy looking mess that’s “sweating” cocoa fats. This can happen when the chocolate gets too warm in storage, but it can also happen when you start mixing things like nuts with chocolate. What happens is that the nut oils start migrating into the chocolate, which forms a eutectic fat. Because the two fats are different shapes, their mixture is unstable, and the melting point of the resultant compound fat is lower than the melting point of either of the individual fats. It turns out that nut oils really like to socialize with cocoa butter, which is a problem. This mixing is the reason that you can tell a fresh Reese’s cup from an older one. A fresh Reese’s cup will have a hard chocolate shell, with the soft peanut butter inside. As it ages, the peanut oil migrates out into the chocolate and softens the chocolate up. This makes older cups soft and gooey, which is either a bug or a feature. (These eutectic mixtures are used to create soft chocolates like Frangos.)
Today was great, because one of my main goals was to learn how to temper chocolate. I now have a great grasp on this topic, including how to debug improperly built chocolate.
CacaoLab 