Why You Need Dark Chocolate For The Richest Mousse
Chocolate mousse is an odd duck of a dessert. It's got a distinctive, light texture which is fluffier than cake but thicker than ice cream. It's made by mixing chocolate with heavy cream and lots of eggs, and it's possible to accidentally scramble those egg yolks into chunks if you overmix your chocolate mousse. However, when it's made right, the best chocolate mousse recipes are velvety and rich and they come apart easily on your fork. Most importantly, a good chocolate mousse has a complicated, bittersweet flavor profile that's undeniably rich.
To pull that off successfully, though, you should be using dark chocolate. The idea is that dark chocolate is more bitter in flavor, and will provide a nice contrast with the eggs and sugar to give your mousse that gorgeously bittersweet taste. It's certainly possible to make a decent mousse with milk chocolate, but since it's already sweeter-tasting, it's easy to make the mousse overly sweet by accident.
Your best bet is to look for a bittersweet chocolate baking bar which has around 70% cocoa on the label (some bakers prefer 60% chocolate while others go slightly stronger than 70%). This means that at least 70% of the chocolate is made from cacao beans rather than other ingredients like sugar. A higher cocoa percentage in chocolate means that it'll have a stronger, bitterer taste, and 70% is generally considered a bittersweet dark chocolate. A bittersweet sweet spot, if you will.
Dark chocolate mousse is bittersweet, not too sweet
For the most part, the airy texture of mousse comes less from the chocolate and more from the air bubbles you create while whisking the eggs and heavy cream together. However, burning your chocolate can still mess up the mousse's texture, which is why you should always use chocolate that melts easily. Fancy restaurants typically opt for special bittersweet baking chocolate, which is higher quality than the grocery store variety and may be tougher to find as a result. Chocolate bars tend to melt easier than chocolate chips, although it does depend on the quality. That isn't to say you shouldn't use chips, since plenty of folks do so without issue. Just be very mindful of burning them during the melting process.
So, what is baking chocolate? Technically speaking, it's chocolate specially designed to melt more easily, but keep in mind that sometimes, when people say "baking chocolate," they're simply referring to unsweetened chocolate. This is a specific type of baking chocolate that is 100% cacao and is too bitter for eating, but it'll give your mousse an extremely intense flavor. It could be worth trying the 70% first and then deciding whether you want the flavor to be even richer. And always check for that all-important cocoa percentage when buying chocolate.