My latest problem at work has been chocolate mousse, particularly the white chocolate kind. When we first started trying to make it – blithely assuming it would be simple – we were all over the shop. My efforts all turned out too firm; one of the other chefs kept producing something like a sort of softly whipped cream that didn’t hold its shape at all. Our third chef hung back, insisting that pastry wasn’t his thing. Only when it was clear that he couldn’t possibly do any worse than the rest of us, did he come forward with his own recipe. His turned out rock solid, and watching him struggling to pipe out little turds of chocolate mousse was – well, I haven’t laughed so much in a long time.
I’m not saying I’ve got it all sorted – because it still goes terribly wrong every so often – but I’ve made God knows how many batches of mousse since that first day, and I’m definitely in a better position now. So I wanted to write down some of the things that helped me, just in case anyone else is struggling with it.
A basic recipe for dark chocolate mousse
The recipe that eventually worked for me was Elizabeth David’s – 30g of chocolate per egg; no other ingredients. You separate the eggs; melt the chocolate in a bain marie, then remove from the heat; stir in the yolks; whip up the eggs whites – adding approximate 1 teaspoon of sugar per egg (as per Felicity Cloake); then fold them into the chocolate mixture.
It’s all about the cocoa content!
A white chocolate mousse – made using David’s recipe – won’t set at all. This is because the ‘setting agent’ in chocolate mousse is the cocoa in the chocolate itself. White chocolate has a very low cocoa content, so you need more than 30g per egg to get it to set.
At one point, we inadvertently bought a different brand of dark chocolate, with a cocoa content of 100% rather than the 54% of the previous brand, which really threw off my mousse-making! The answer is fairly obvious though: if the chocolate has a higher cocoa content, one needs less of it. So for 100% cocoa chocolate, I used just 23g of chocolate per egg. Also, 1.5 teaspoons of sugar when whipping the egg whites, to counteract the bitterness.
A partially-there recipe for white chocolate mousse
For the white chocolate mousse, I settled on 50g of chocolate per egg. I don’t use the yolks because they affect the colour, and I don’t add sugar to the egg whites because the white chocolate has so much sugar in it anyway. I still think the meringue needs stabilizing though, or else it will split – sometimes after it has been combined with the chocolate. So first, don’t over-whip the egg whites – stop just before you reach stiff peaks. Also a tiny bit of cream of tartar, just the tip of a teaspoon, seems to help. With white chocolate mousse, I also add cream to dilute the sweetness: 70ml per egg – and see the point below.
Watch the temperature
For the longest time, when I added the cream to the melted chocolate first, before the egg whites (as one is supposed to), the mixture took on a lumpy, appearance – not seized, but as if it were curdled. I resorted to adding the cream last and the egg whites first, which produced a smoother mixture, albeit without the lovely airy texture of a mousse.
I think these problems were down to temperature. To get over them, I tried Michel Roux’s approach of making additions to the chocolate progressively cooler. (Roux uses gelatin in his white chocolate mousse, which sounds like cheating to me.) I heat half of the cream in the microwave until it is just warm to the touch, and add this to the melted chocolate gradually. I then whip the other half of the cream to firm peaks and combine that with the chocolate mixture. Then I fold in the whipped egg whites.
It doesn’t sound so important, but there are lots of points during the making of mousse where it feels like you just need a moment to beat the lumps out of the mixture… and at this point, everything will start going south quickly. A really light hand is needed – not just when folding in the egg whites – but also, for example, when adding cream to the white chocolate, or yolks to the dark chocolate. As the liquid is stirred into the hot melted chocolate, it will start to thicken. The more it is beaten, the thicker, and stickier and lumpier it will become. So stir slowly and gently, and only enough to incorporate the liquid before moving on to the next stage.
Recipes in summary
Dark chocolate (54% cocoa): use 30g of chocolate per egg. Separate the eggs, and whip the whites to firm peaks, adding 1tsp of caster sugar per egg. Melt the chocolate over a bain marie, then remove from the heat. Stir in the yolks slowly, then fold in the beaten egg whites.
Dark chocolate (100% cocoa): as above, but use 23g of chocolate and 1.5 tsp sugar per egg.
White chocolate (very low cocoa percentage): use 50g of chocolate per egg (you will only need the whites), and 70ml of double cream. Divide the cream into two bowls. Melt the chocolate slowly and gently over a bain marie. Warm one bowl of cream and add gradually to the melted chocolate. Whip the other to firm peaks, and combine with the chocolate mixture. Beat the egg whites with a little cream of tartare to stabilize and fold through the chocolate mixture.