Converting recipes for different % cocoa in chocolate

[Bojana]

Are there rules how to convert recipes if you change the type of chocolate you work with. Going from 66% cocoa to 55 or even 39%? I am mainly takling chocolate mousse, cremeux, ganache etc, not pure chocolate applications such as bonbons.

 

I can see adding extra gelatine or reducing liquids could work but how do you go about it?

[ElainaA]

Alice Medrich discusses this in her book  Bittersweet. The appendix, titled Chocolate by the Numbers, gives formulae for substituting one type of chocolate for another. However her main focus is on substituting chocolate with a higher percentage label for chocolate with a lower percentage. She does discuss issues with mousse, brownies and tortes as well as ganache.

Elaina

[ChrisZ]

I'm no expert but I thought the main issue is sweetness.  There is always variations between brands but generally the higher the % the less sweet / more bitter.  It can come down to personal preference but if you're using a very high % cocoa then always taste as you go in case you need more sugar.  And the opposite is true as well, if you're using a lower % cocoa - especially down below 50% - then depending on the brand of chocolate it may be sweeter than the recipe creator intended.

[ElainaA]

It is actually more complicated than that. Higher percentage chocolate has less cocoa butter than lower percentage chocolate so the fat content needs to be adjusted also. Medrich says " the effect of using a higher percentage chocolate is a little like adding cocoa powder to a recipe and subtracting sugar at the same time. That just begins to explain dry cake batter. dense gummy mousse and ganache that curdles." (Medrich, Bittersweet,2003, page 345) She (nor anyone else that I have read) does not discuss adjusting recipes to use lower percentage chocolate. However I would assume that you would need to adjust the fat content here also.

Elaina