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Melt into chocolate science

A delicious new encyclopedia, edited by world-renowned chef pâtissier Frédéric Bau, takes some of the mystery out of the dark stuff

At first sight, there is no difference between one bittersweet chocolate with 80% cocoa content and another bittersweet chocolate with the same cocoa content. Yet, there can be a world of difference. From one make to another, from one origin to another, from one manufacturing process to another, the aspect, aromas, texture, and melting quality vary radically. Where do these differences stem from?

The terroir

The concept of terroir in chocolate-making was unknown until the early 1990s. Chocolate comes from the cocoa pod, the fruit of the cocoa tree. Like all agricultural crops the beans are influenced by factors that together make up what we call terroir: origin, choice of varieties, environment, and expertise.

There are three main varieties of cocoa trees – Criollo, Forastero and Trinitario and each produces cocoa with different characteristics. Forastero, for example, is more bitter and astringent, while Criollo is mellower, with notes of berries, nuts, and honey.

These subtle differences underpin the construction of the taste of chocolate. In addition to the variety, environment is an important factor. Sunlight influences the polyphenol content, and rain plays a role in fermentation. And the work of the farmers can modify the aromas of the product. When the pods are cleaved open, and during the processes of fermentation and drying, the slightest bit of inattention might well produce an unwanted aroma, such as a taste of mould or smoke, or excess acidity.

These factors, which vary from one plantation to another and from one year to another, influence the final aroma. Yet they are not enough to guarantee the quality of a chocolate.

Just like a wine producer who makes optimal use of his terroir to imprint his signature on his wine, a master chocolatier who knows how to get the most out of his plantations will leave his mark on a good chocolate.

Terroirs and aromas

Unlike wine, it is difficult to link a terroir to a chocolate taste, because varieties of cocoa are less distinct than those of vines.

In the plantations, farmers have cultivated their own mixtures. In addition, research on cocoa plants has concentrated on increasing yields and combating disease rather than on defining aromatic profiles. But artisans and chocolate lovers have been increasingly emphasising the links between terroir and taste. Perhaps it will develop to the point where appellations of origin will be established.


The creation of a chocolate involves working to a recipe. Labels on mass-produced bars give the impression it is all very simple: a minimum cocoa percentage, indicating the presence of cocoa paste and cocoa butter; sugar, a little soy lecithin, natural extract of vanilla—and nothing else.

The adjectives to describe chocolate – intense, elegant, sleek, subtle, sublime – rarely give any indications of the provenance and the quality of the cocoas used. For good reason: all the information is based on the percentages of cocoa and sugar.

Although they do not talk about it, industrial chocolate producers must ensure that the aromas of a 60%, 70%, or 80% cocoa chocolate are always

uniform. To do so, they must determine a mixture of beans with identical or equivalent aromas.

Master chocolate makers are like cellar masters who have to guarantee the stability of a blend, in the same way the assembly of a single malt and single grains ensures a whisky remains identical over time.

Certain artisan chocolatiers and a few industrial producers, such as Valrhona and, more recently, Nespresso, go further, showcasing the characteristics of each terroir by defining an aromatic profile of the chocolate. They seek to establish a typical taste when they work on the composition.

‘Grand cru’

In 1987, Valrhona was the first to launch a grand cru chocolate, created entirely from Caribbean Criollo cocoas. In 1998, Valrhona went even further when it developed the first single-origin domain chocolate: Gran Couva 60% from Trinidad.

Blended grands crus combine cocoas of various plantations in various producing countries; terroir grands crus comprise cocoas from a single producing country, and single-origin chocolate comes from a single plantation. The mouth-feel of a 70% Andoa bittersweet (a blend of grands crus) is completely different from that of a 68% Nyangbo (a single-origin grand cru), not in terms of intensity, but in terms of aroma, texture, and “colour.”

The first has a little bitterness, with notes of citrus fruits and roasted coffee, while the second is more “chocolatey,” with notes of mild spices and roasted nuts. The work of master chocolatiers involves finding what proportion of chocolate and sugar, and which cocoa associated with another, will give the best result.

Today, there are two trends in the chocolate industry: those who favour a return-to-childhood chocolate, and those who seek out authenticity, the raw nature of the original cocoa, and who are happy to bring out the bitterness of the beans in the final product.

Between these extremes, an infinite number of combinations is possible.



Quality depends on the cocoa percentage

False. The percentage indicates the proportion of cocoa (paste and butter), but gives no indication of the country of origin, the quality of the cocoa, or the expertise of the chocolate maker.

Higher cocoa percentage means a more bitter chocolate

False. When 70% cocoa is shown on the label of a bar, the remaining percentage indicates the sugar. One might think the more cocoa, the less sugar. But some beans produce a mellower, sweeter chocolate. Some 80% cocoa chocolates are inedible, while some 85% cocoa chocolates are powerful and aromatic without being bitter.

Cocoa butter is added to chocolate

True. The cocoa butter added at the end of the process forms a film of lipids that gives chocolate its unctuousness and facilitates the work of artisan chocolate makers. On average, about 10% cocoa butter is added to the chocolate paste, but the overall proportion of cocoa butter is higher as it is already present in the chocolate paste.

White chocolate contains no chocolate paste

True. To make white chocolate, only cocoa butter, sugar, and powdered milk are required. These components explain the absence of a chocolate colour and the sweetness of white chocolate, which contains only 20 to 30% cocoa butter in addition to 55% sugar.

Couverture chocolate is good-quality chocolate

True and false. It is the basis for all the chocolates bought by professionals. It is called couverture (from the French verb couvrir, to cover) because it is used to coat chocolate bonbons and to make moulds. There is only one difference, and that is in its presentation form: couverture chocolate may be sold in large chips or buttons, or in bars.

A chocolate that has whitened should be thrown out

False. Whitening, or streaking, is a change in appearance that has little influence on the taste. It is caused by inappropriate storage or inadequate tempering, but is not toxic. Chocolate that has whitened is perfectly edible.


Chocolate Soufflé



1 pastry brush

6 individual soufflé moulds or ramekins


Ingredients - serves 6

A little butter, melted, to grease the soufflé moulds

A little sugar to sprinkle over the greased moulds

5 ½ oz/150g bittersweet chocolate, 70% cocoa

4 eggs, separated

3 ½ oz/100g sugar

1 heaped teaspoon unsweetened cocoa powder

1 heaped teaspoon cornstarch

200ml whipping cream



1.  Using a pastry brush, butter the moulds lightly. Then sprinkle them all over with sugar. Turning upside down to remove any excess. Set aside in the refrigerator.

2. Chop the chocolate and melt it slowly in a bain-marie or in the microwave oven (on “defrost” or at 500W max, stirring from time to time).

3. Slowly whisk the egg whites, gradually adding sugar until they form soft peaks.

4. Sift the cocoa powder and cornstarch together. Pour the cold cream into a pan and add the sifted ingredients. Bring to the boil, stirring constantly. When it starts to thicken, remove from heat and slowly pour one-third over the melted chocolate.

5. Using a flexible spatula, mix it in energetically, drawing small circles to create an elastic, shiny ‘kernel’. Repeat twice more with the rest of the cream.

6. Add the egg yolks, whisking energetically until the texture is smooth and shiny. Carefully fold in one-third of the whisked egg whites with a spatula. When the consistency has been ‘lightened’, carefully fold in the remaining egg whites.

7. Fill the moulds to the top, cleaning the rim so that the batter does not stick to it and so the soufflés can rise straight up. Chill until they are to be baked.

8. About 30 minutes before serving, preheat oven to 425°F (210°C-220°C).

9. Remove the soufflés from the refrigerator and bake for 10 to 12 minutes, until well risen with a nicely done crust. Serve immediately.


Extraordinarily Chocolate Tart



1 tart mould

1 kitchen thermometer

2 sheets food-safe acetate or parchment paper

1 pastry brush


Ingredients - serves 6 - 8

Almond shortcrust pastry:

4 oz/120g butter, room temperature

½ teaspoon (2g) salt

3¼ oz/90g confectioners’ sugar

½oz/15g ground blanched almonds

1 egg

Self-raising flour, divided: (2 oz/60 g) plus (6 oz/180 g)


Bittersweet chocolate ganache: 12oz/350g bittersweet chocolate, 70% cocoa

250 ml/250g whipping cream

15ml acacia honey

3 tablespoons plus 1 teaspoon (1¾ oz/50g) butter, diced

A little melted chocolate to brush the tart shell



1. Prepare the almond shortcrust pastry. Soften the butter and combine with the salt, confectioners’ sugar, ground almonds, egg, and 2 oz/60 g cake flour. As soon as the ingredients are mixed, add the remaining flour, and mix quickly, until just combined

2. Roll out the dough to a thickness of 3 mm between two sheets of acetate or parchment paper. Place it, flat, in the freezer for 30 minutes

3. When the dough has hardened, peel off the sheets and cut to the desired shape. Line your tart mould or pan with the dough and return it to the refrigerator for 30 minutes  so it retains its shape during baking, then preheat the oven to 300°F-325°F          (150°C-160°C) and bake for about 15 minutes, until it turns golden. Leave to cool

4. Prepare the chocolate ganache. Chop the chocolate and melt it slowly in a bain-marie or in the microwave (on “defrost” or 500W max, stirring occasionally).

5. Bring the cream to the boil with the honey.

6. Gradually pour one-third of the cream over the melted chocolate. Using a flexible spatula, mix energetically, drawing small circles to create an elastic, shiny ‘kernel’. Repeat this step twice more with the rest of the cream.

7. When the temperature cools to 95°F-104°F (35°C-40°C), stir in the diced butter. Process for a few seconds using an immersion blender so that the mixture is smooth.

8. Brush a fine layer of melted chocolate over the cooled tart shell to seal. As soon as it hardens, pour in the ganache and chill for two hours. Serve at room temperature.


Chocolate-Vanilla Marble Loaf


1 loaf tin (8 cm×30cm×8cm)

2 piping bags


Ingredients - serves 6 - 8

Vanilla batter: 8 egg yolks

8oz/220g granulated sugar

120 ml whipping cream

1 vanilla bean

3 g baking powder

2 ⅓ oz/65 g butter, melted and cooled

1 cup plus generous ¾ cup (5 ¾ oz/165 g) self-raising flour

Chocolate batter: 2½oz/70 g bittersweet chocolate, 70% cocoa

4 egg yolks

4 ¼ oz/120 g sugar

70 ml whipping cream

2 ¾oz/80 g cake flour

5g unsweetened cocoa powder

2g baking powder

20 g grape-seed oil



1. Prepare the vanilla batter. In a mixing bowl, combine the egg yolks with the sugar. Add  the cream. Slit the vanilla bean lengthways and scrape out the seeds into the mixture. Sift in the flour and baking powder and incorporate them into the batter, then stir in the melted butter. Set aside.

2. Prepare the chocolate batter. Chop the chocolate and melt slowly in a bain-marie or in the microwave oven (see above).

3. In a mixing bowl, combine the egg yolks with the sugar, then stir in the cream. Sift the flour, cocoa powder, and baking powder together into the mixture and stir in. Then stir in the melted chocolate and grape-seed oil until just blended.

4. Preheat the oven to 300°F (150°C). Line the loaf pan with parchment paper. For an attractive marbled pattern, pipe out one-third of the vanilla batter over the bottom of the pan. Then pipe out half of the chocolate batter lengthways through the centre.

Cover this with one-third of the vanilla batter and pipe the remaining half of the chocolate batter lengthways through the centre.

Cover it with the remaining vanilla batter. Bake for 50 minutes to 1 hour, until the tip of a knife comes out clean.

5. Turn the cake out onto a cake rack and leave it for about 10 minutes on its side so that it retains its shape.

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