70% chocolate shows total content of ingredients made from cocoa beans (cocoa butter and cocoa liquor). For example, 100 g of 70% chocolate can contain 30 g of sugar (30%), 60 g of cocoa liquor (60%) and 10 g of cocoa butter (10%).
The percentage of cocoa butter (the percentage of fat) is usually showed on the label of a wrapper of the chocolate. Let’s introduce a concept “factor – the percentage of cocoa butter per 100 g”. So if there is 70% chocolate (28% of cocoa liquor and 42% of cocoa butter) in a recipe:
- 1000 g heavy cream (35%)
- 890 g chocolate A (70%)
- 100 g invert sugar
- 200 g fresh butter
and you have only chocolate B which contains 64% of total content of ingredients made from cocoa beans (cocoa butter and cocoa liquor) and you know that it contains 38% of cocoa butter. You have to calculate how many grams of couverture chocolate B you will need to take instead of 70% chocolate (used in the recipe).
- factor A (70% chocolate) = 42% (cocoa butter) / 100 = 0.42
- factor B (64% chocolate) = 38% (cocoa butter) / 100 = 0.38
In order to re-calculate the amount of chocolate we need let’s use the followng formula:
The weight of chocolate B = (the weight of chocolate A * factor A) / factor B
In our particular case the weight of chocolate B = 890 * 0.42 / 0.38 = 983.6 g, i.e. we need to take 984 g of 64% chocolate (with 38% of cocoa butter) for this recipe.
Taking into account the re-calculated amount of chocolate the recipe will look like this:
- 1000 g heavy cream
- 984 g chocolate (64%)
- 100 g invert sugar
- 200 g butter