Today was 100% lab work, mainly working around a chocolate enrober. This is the machine that coats stuff in chocolate. It works by creating a curtain of tempered chocolate that the center passes through, then sends it down the line to a cooling tunnel that sets the chocolate up. The other ways of coating in chocolate are shell molding, which lets you create goodies with a liquid or semi-liquid center, and panning, which creates items like chocolate covered peanuts or raisins. Being that my dream is to create a chocolate on par with Pralus or Amadei, it’s not really a core concern for me, but it was fun to learn how to make chocolate sit up, beg, and roll over.
My lab station was to run a Tricor Tempermeter, which takes in liquid chocolate, thinks about it for a while, and tells you if it contains the right amount of crystallization. How? More temperature tricks. Crystals are more stable than amorphous mixtures, so when crystals are formed, some amount of heat is released (called, imaginatively enough, the heat of crystallization.) so, the machine takes the liquid sample to a reference temperature, then starts chilling it. At a certain point, crystals will start forming very quickly if the chocolate is tempered. This is going to create heat from the chocolate. So, if you graph the temperature of the mass as you chill it at a constant rate, tempered chocolate will get a curve with an inflection point. No inflection, no temper. Too much inflection, and you are overtempered. Because going out of temper can ruin a whole production run, you have to keep measuring temper, so I was a busy guy.
We were also running experiments in keeping a chocolate in temper for several hours, and “statically” tempering chocolate by just keeping it for a very long time at 91F. We had to measure the temper of these results every hour, while also tracking the temper of the chocolate in the enrober. Doing this enough times, I got to the point that I could predict temper by looking at the surface of the chocolate and how it set up.
We did a long comparison session in the lab also. This was divided into four parts: testing the previously made chocolate, tasting different roast levels, tasting different conching levels, and preparing for taste reverse engineering milk chocolate on Friday.
Previously made chocolate tasting. On Monday, we started making dark chocolate (at about 50% cocoa content, which is pretty sweet for my taste) with a conventional refiner/conch, dark chocolate in a ball mill, milk chocolate with spray dried milk, and milk chocolate with milk crumb. We tempered most of these yesterday, and tasted them today in the unrefined, unconched, and finished forms. All of them turned out pretty well, though the conventional dark was overconched, and hence pretty flat. Conching gets rid of bad stuff (acetic acid), but also all the good tasty notes. The milks were very good also. The interesting part for me was how well the ball milled chocolate turned out. This would actually be pretty easy to make in small batches! Basically, to make it, we put the basic, unrefined ingredients into a sphere formed by two welded together salad bowls. Along with the ingredients, the instructor put some stainless steel shot of various sizes, and hooked the whole assembly to a motor. The tumbling motion of the balls refined and conched the chocolate at the same time, and it turned out better than the conventional stuff. Building the mill looked pretty doable, and I’ll experiment with this when I get home.
Roast/conch levels. The instructors brought out liquid dark chocolate made with lightly roasted, medium roast, and burnt beans. The difference was pretty dramatic. The lightly roasted chocolate was pretty acidic, the medium roast pretty chocolately, and the burnt had huge grassy/seedy/beer notes. The former brewpub owner in the class actually preferred this roast, as he said the notes were reminiscent of the bitter parts of a really dark beer. I would have loved to do a much wider tasting, with a matrix of bean types and roast levels. We also tasted dark chocolate conched for 24 hours and 48 hours. The 48 hour, as predicted, had a lot of flavor removed. It was sweet, and a little chocolatey, but missing any of the bitter/acid/astringent/fruity notes from the 24 hour. An interesting note from the discussion after this tasting: Guittard (and others) age their high end chocolates! Aging allows the sugar particles in the chocolate to take up the flavor from the volatiles in the cocoa solids, leading to a a deeper, longer lasting taste. Sugar treatment is also critical. Since you want small sugar particles, you typically pulverize the sugar. Pulverized sugar has lots of surface area, and it’s not protected like crystallized sugar is, so it starts taking up any ambient flavors in the air. Different types of sugar also have different levels of crystallization, and also different levels of ash in the sugar. (Yes, that’s right, ash…it happens whenever you grind or heat stuff, apparently.) Crushing the sugar particles along with the cocoa in the refining process should lead to a cleaner taste, since the vulnerable surface area is protected.
Reverse engineering. We had a training panel also, using five different milk chocolates, leading up to a competition on Friday to see who can best decipher the contents of various commercial milk chocolates. The “milk” in milk chocolate comes in many different forms (as described in Monday’s notes) and we tasted five today: spray dried, skim milk powder with added butter oil, cream powder, roller dried, and crumb. They all melt differently in the mouth, and they all have different residual dairy tastes, ranging from cheesy to buttery to creamy to caramel. We’ll see how I do on Friday establishing that I’m not just imagining this. We also discussed Hershey’s chocolate, which is really, really wierd! If you actually taste Hershey’s chocolate, you’ll notice some very distinct dairy/acidy notes. This chocolate formulation is ONLY sold in the United States. Even Canada can’t deal with this stuff! Where does this come from? Milk fat and lipases. Lipases break down lipids (ie, fats), and Hershey’s is hypothesized to be full of the stuff. This breaks down the milk fat into other compounds that form that taste, well, kind of barnyardy. Why do Americans like it? Dunno, Why do the British like Marmite?
Lastly, did a little shell molding today and made chocolate covered cherries. I’ll skip the details for now.