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Conching: Crucial Step in Chocolate’s Flavor and Texture?
Traditionally, the manufacture of chocolate includes a stepcalled “conching”, often thought to be important in chocolate’s complex flavor and smooth texture. Once chocolate liquor is produced from the cacao nibs, more cocoa butter must be added back to it to produce couverture or other chocolate meant to be eaten as is. To that mixture is added sugar, milk powder (in the case of milk chocolate) and flavorings, such as vanilla or spices. This mass is heated and undergoes further grinding to reduce particle size, after which conching begins.
Originally, conches were long stone receptacles in which the chocolate mass was pounded, often with stone balls and usually for multiple days (!). The process takes its name from conch shells, which the receptacles resembled in shape. Once mechanization arrived, the chocolate mass was “kneaded” in conches with heavy rollers, which moved back and forth through the chocolate at a regulated speed, making for a far less laborious conching. More modern conches are rotary, with mixing blades that work the mass in a longitudinal motion. Chocolate undergoing conching begins as a doughy or powdery mass, but ends up as a thick fluid. And there are present-day manufacturers who have done away with the conching process altogether, substituting instead an emulsification process that uses a machine resembling an eggbeater.
For how long is chocolate conched? In older equipment, conching periods can range from a few hours up to a few days or longer, and opinions on timing tend to vary widely. Some reports indicate that fine-quality chocolate is conched for up to 96 hours, some insist the conching period is as long as five days, and one article maintained that good chocolate is conched for a minimum of one week. Most chocolate-makers, however, will tell you that chocolate needs to be conched until it’s done. That may seem deliberately vague, but much depends upon what kind of chocolate you’re trying to make, what beans you start with, and many other factors. Mott of Grenada Chocolate states that bulk cocoa beans (often a product of West Africa) need less conching (sometimes, very little conching), because the chocolate liquor produced from them needs to be rid of far fewer strong and “off” flavors. On the other hand, he says, chocolate mass made from fine-flavored cocoa beans usually requires a good deal of conching to bring out the desired taste in the finished chocolate. In any case, modern rotary conches are changing chocolate manufacturing, because they reduce the length of the conching process significantly and can handle enormous quantities of chocolate at one time (in some cases, over 5 tons!), although not all manufacturers will use them. It’s important to remember here that longer conching time doesn’t always mean better chocolate; you have to start the process with good ingredients that have been handled properly, and it is possible to overconch chocolate (one source I’ve seen claims that doing so will result in gummy chocolate; others say the chocolate will just taste flat).
But what does conching accomplish, that it has long been considered so vital a part of chocolate manufacturing? That depends upon your source of information. It is usually said that conching is important to the flavor development of chocolate. Art Pollard, of Amano Chocolate, notes that conching improves the flavor of chocolate by allowing “various volatile flavor components…present in the cocoa bean” to evaporate; these include acetic acid, as well as other acids, by-products of the fermentation of the cocoa bean. Pollard states that many of these components are harsh-tasting; once these are allowed to evaporate, the chocolate flavor can more fully express itself. It’s also been written that the agitation and aeration taking place during conching help to develop the chocolate flavor, perhaps in a manner suggested by Pollard, who believes that the flavor components of chocolate are infused into the cocoa butter and other ingredients during the conching process. Given that chocolate contains at least a few hundred flavor components, not all of which are known or understood well, he may have a point.
Conching may also reduce the size of particles in the chocolate mass (or alternatively, simply smooth the particles out). The importance of this cannot be overstated, as good chocolate should be perfectly smooth on the tongue. In theory, at least, conching accomplishes this via friction. Pollard asserts that the solid particles in the chocolate (including sugar grains and cocoa particles (cocoa particles are made partly out of cellulose, a naturally-occurring plant fiber)) “rub against each other”, causing “the edges on the particle to wear and the particles to become rounder and smoother”, not unlike rocks tumbled repeatedly in a stream. John Nanci, of Chocolate Alchemy, reports that your tongue can no longer determine texture when particles drop below about 50 micron in size, and writes that, ideally, the refining (reduction of particle size) that takes place during conching will reduce the vast majority of particles in the chocolate mass to roughly 18 to 20 micron ( just so we’re all on the same page, 50 micron is a little smaller than 0.002 inches!).
It has also been suggested that conching drives off any excess moisture in the chocolate, which may assist in the evaporation of volatiles. Although the amount of moisture remaining in the chocolate liquor is low (roasting the cocoa beans drives off most of it), conching may help reduce moisture content slightly.
So why the question mark in the title? If everyone knows that conching plays an essential role, what’s the need for speculation? Because not everyone agrees that conching is required for a good-quality product. In the January, 2003 issue of Food Processing Magazine, Managing Editor John Gregerson authored an article in which he questioned what really happens during the conching process. In that article, Gregerson quotes Dr. Gregory Ziegler, an associate professor of food science. Ziegler reported that, in a triangle taste test conducted at Penn State with a panel of twenty members of the confectionery industry, none could tell the difference between conched and unconched milk chocolate. The same thing happened at another taste test held in Munich; industry professionals couldn’t differentiate between conched and unconched chocolates. Over time, Ziegler’s studies have been unable to show a significant reduction in either acid or moisture levels during the conching process. Ziegler believes that chocolate may undergo minute changes during conching, depending upon methodology, temperature, ingredients, and other factors. Other sources have indicated that the addition of the emulsifier soy lecithin to the chocolate mass eliminates much of the need for conching, as that lecithin would coat any sugar/cocoa particles and reduce their rough edges on its own.
So what’s going on here? Have we been hoodwinked by chocolate manufacturers? Is the conching process just a long-term scam of enormous proportions? I don’t think so. My own belief is that conching was originally a necessity for better-quality chocolate. Manufacturing methods were crude, or at least not as sophisticated as they are now. Without conching, a chocolate bar in the late 1800’s or early 1900’s might well have been gritty and harsh in taste. These days, even with far more sophisticated equipment and much-improved knowledge of chocolate chemistry, I believe that what happens in conching might not be entirely understood. It’s possible that any alterations in the physical or chemical composition of chocolate during conching may indeed be subtle. But given chocolate’s sensitivity to its environment in general (chocolate is notorious for being affected by temperature, moisture, proximity to other foods, and more), even small changes may make a big difference in the finished product.
Food manufacturing is no less subject to trends than is any other aspect of life. Unconched chocolate may become all the rage at some point. But until it does, I’ll continue to enjoy my chocolate conched, thankful that a little mystery in its manufacture can help me enjoy it all the more.
Special thanks to Art Pollard of Amano Chocolate, John Nanci of Chocolate Alchemy, Mott of Grenada Chocolate, and Donald Scott of Precinct 13.
A brownie base, a layer of marshmallow, a dark chocolate glaze, and a topping of toasted almonds; what could be bad? This is a somewhat more adult version of rocky road brownies, but they retain a bit of childhood nostalgia, too. They have great color contrast and look appealing on a plate. Make sure the miniature marshmallows you use are soft and fresh; you’ll need about half of a 10.5 ounce bag to make these brownies. Use whole almonds (with the skins on) here and chop them fairly coarsely. Other nuts can be substituted for almonds, if you prefer; try dry-roasted, unsalted peanuts or use pecans or even hazelnuts.
These are not difficult to make, but they take a little time. You’ll need very good quality chocolates, especially for the glaze. Store these in the fridge, where they’ll last for at least five days if in airtight container. These freeze very well, at least in the short-term. (Defrost them, still in wrappings, in the fridge.) Allow the bars to stand at room temperature, lightly covered, for about 20 minutes before serving, as they’ll have much more flavor with the chill off. Note that these must stand at least 6 to 8 hours before they are cut into bars, or the marshmallows will be too sticky.
3/4 cup coarsely chopped, skin-on almonds
7 Tbsp. unsalted butter, cut into thin pats
3 ounces semisweet chocolate, finely chopped
1 ounce unsweetened chocolate, finely chopped
3/4 cup plus 1 Tbsp. granulated sugar
Pinch of salt
1 tsp. vanilla
2 eggs, graded “large”, preferably at room temperature
1/2 cup unbleached, all-purpose flour, fluffed with a fork before measuring
3 cups soft, fresh, miniature marshmallows
4-1/2 ounces semisweet chocolate, finely chopped
1-1/2 ounces unsweetened chocolate, finely chopped
Few grains of salt
6 Tbsp. unsalted butter, cut into thin pats
1 Tbsp. light corn syrup
1 tsp. vanilla
Adjust rack to center of oven. With aluminum foil, line a shallow baking pan large enough to hold the chopped almonds in a single layer. Place the almonds into the foil-lined pan and set aside. Using heavyweight aluminum foil (or two lengths of regular weight foil), line a 7 by 11 inch baking pan (the pan MUST be at least 1-3/4 inches tall) so that the foil is shiny side up. Press out as many creases on the inside of the pan as possible, and fold the overhang back against the outer edges of the pan. Measure the marshmallows (I use a 4 cup liquid measure for that), then cover tightly with plastic wrap and let stand at room temperature until needed (covering them prevents them from drying out).
Make the brownies: In a two quart, nonaluminum, heavy-bottom saucepan, combine butter slices and both chocolates. With small whisk or slotted spoon, stir over very low heat until almost melted. Remove from heat; stir until melted and smooth. Allow to stand at room temperature 10 to 15 minutes, or until bottom of pan is only slightly warm. Meanwhile, preheat oven to 350 degrees F.
When pan bottom is only slightly warm, add to melted chocolate mixture the sugar, salt, and vanilla. Stir in well. Beat eggs with a fork until blended. Add half of egg mixture at a time, beating in after each addition to incorporate. Scrape down bottom and sides of pan with rubber spatula. Stir in flour just until incorporated. Turn batter into foil-lined 7 by 11 inch pan and spread level; it will be a thin layer.
Bake in preheated oven 14 to 17 minutes, turning back-to-front once about halfway during baking time. Test for doneness by inserting a toothpick diagonally near the center of the brownies; if it emerges with only a few moist crumbs clinging to it, brownies are done. Do not overbake. Remove to cooling rack, but leave oven on.
Immediately scatter miniature marshmallows all over the top of the brownie layer. With your hand and fingers, move marshmallows as necessary so they form a single layer all over the top of the brownie layer, right to the edge of the pan. (Be careful here! The pan is still hot!) With your palm and fingers or the back of your hand and fingers, press marshmallows gently into brownie layer. You’ll see a few spaces where the brownie layer shows through, but there shouldn’t be many of them and they should be small. Allow to stand on cooling rack until cooled completely.
Meanwhile, place the shallow pan with the almonds in it into the heated oven. Toast the almonds for 9 to 12 minutes, stirring frequently, until they take on a light golden color (watch carefully; nuts can burn quickly). Remove from oven. Stir in pan for a few minutes to cool slightly, then allow to stand at room temperature until cooled completely. (You can toast the almonds before you make the brownies, if you prefer.)
When the marshmallow-topped brownie and almonds are cooled to room temperature, make the glaze: In a medium microwaveable bowl, combine finely chopped chocolates, salt, and butter. Microwave at 50% (medium) power for 1 minute; stir thoroughly. Microwave at 50% (medium) power for further, shorter intervals, stirring well after each, until almost melted, then stir until melted and smooth. Stir in corn syrup and vanilla.
In a fine stream, pour glaze all over top of marshmallows. Quickly spread glaze evenly over top (a small offset spatula is very helpful here; you can also shake the pan gently to level the top). Immediately, before glaze has a chance to set, sprinkle cooled, toasted almonds evenly all over the top of the glaze. With the back of a tablespoon, gently push the almonds into the glaze.
Allow to stand at room temperature until glaze is set. Cover tightly; allow to stand at room temperature at least 6 to 8 hours (overnight is just fine) before cutting into bars. To cut, remove block of brownies, still in foil lining, from pan; place on large cutting board. Gently peel back foil from edges (some marshmallow may stick to the foil, but that’s OK). Use a large, very sharp, straight-edged knife, cutting down with the full length of the blade, to cut the block into 24 bars.
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I favor substance over style. While nobody is more pleased to open a box of beautiful chocolates than am I, nobody is more disappointed when they turn out to be all about appearance, without good flavor to match. And it’s great to find a chocolatier who thinks along similar lines, as does William Poole, head chocolatier of Wen Chocolates. Mr. Poole has an interesting background, one that includes working for the largest caterer in Slovenia as well as a stint as Pastry Chef on the American Orient Express, a luxury private train. With experience like that, he understands that food has to look good, but in his chocolates, those good looks don’t come at the expense of taste. If I had to use one word to describe these chocolates, it would be “honest”. They are obviously turned out by a professional, though they are less flashy in appearance than some others. But, unlike those others, Wen Chocolates have genuine, and genuinely delicious, flavor.
What to try? Go for the “One of” Collection, which includes one of each of the truffles. Even if you think you’re not a caramel fan, try the Prazen Sladkor Truffle, with the mysterious “William’s Wicked Caramel” covered in dark chocolate. Try the Troika Truffle---dark chocolate with accents of black teas and citrus. Or go for the Mint Julep Truffle, with a center of bourbon-and mint-infused milk chocolate, crowned with candied mint leaves. If you want a change of pace, Wen Chocolates offers chocolate “tiles”, toffee, and even Marzipan z Marelica, a raspberry-cured marzipan covered in milk chocolate and decorated with lustre dust. Because this is a very young company, the packaging is not as elaborate as that you’ll find elsewhere. More sophisticated packaging will likely come along a bit later, and the current rabbit logo sealed onto each box is very charming and truly distinctive (in ancient Egypt, the rabbit symbolized the word “wen”, which meant “to exist”, and very appropriate, too; would we really want to exist without chocolate?). Seasonal specialties, as well, but order early; this is a small business. Order online at www.wenchocolates.com, call them at (720) 891-4622, or visit the shop at 1801 Wynkoop Street in Denver, CO, in the Mise en Place Cooking School. Check ‘em out!
Stephanie (email@example.com) has had a strong affinity for chocolate from a very early age. Family members claim that, as a child, she was able to hear chocolate being opened in the kitchen no matter where she was in the house. Stephanie was baking by the time she was 6 and ran a short-lived baking business out of her parents’ kitchen when she was in high school. She has a Master’s Degree in Foods from Virginia Tech but no formal training in cooking or baking. Consequently, she is a home cook, not a chef. Prior to beginning this column, she had written about chocolate for some 8 years.