What’s the science behind flavor and viscosity in sipping chocolate?

At Flowstate, we have experimented with lots of sipping chocolate in the kitchen. A key lesson: you need heat to unlock the potential for flavor and mouthfeel of sipping chocolate. What’s the science behind this?

The same thing happened earlier today at 5g Coffee House. I brought the owner, Ricardo, a couple of single origin cacao liquor, to see if he would like to serve it in his cafe. The goal was to use the espresso machine to create sipping chocolate, similar to what I saw in Singapore (see video).

We first tried melting the cacao liquor with the hot water spout, then added steamed milk. It failed to bring out the flavor.

I’ve encountered crazy serendipities in this journey multiple times. It happened again today. It just so happened that one of Ricardo’s mentors, Tido, was hanging out in the cafe. It turns out Tido is a food pro and have tried single-origin sipping chocolate in several countries.

Tido placed the cacao liquor, sugar and milk in a frothing pitcher, then steamed the entire mixture. The result was the same as the best we have made in the kitchen and what I’ve tried in Singapore. I don’t have footage but the procedure is the same as what I’ve seen at The Dark Gallery.

What’s the science behind this? Here’s my guess. Cacao liquor and chocolate, whether tempered or not, is a mixture of cacao butter and cacao solids.

When mixed with milk without applying enough heat, a lot of the flavor is trapped in “microclumps” of cacao butter and solids swimming in a sea of milk. The taste buds could only sense the outer surface of these clumps.

If heat is applied, the clumps of cacao butter and solids are dispersed, allowing the taste buds to sense more of the butter and more of the solids, giving that silky and more complex flavor.

The one on the left is simply a suspension. While there may be stronger bonds between water molecules of the milk and some solids, most of the interactions are the weak bonds between water molecules, thus producing an inviscid liquid.

On the right, the cacao solids or the casein in milk may act as an emulsifier between the water molecules in milk and the fat molecules of the cacao butter. The water-to-emulsifier and fat-to-emulsifier bonds are stronger than water-to-water bonds, thus the greater viscosity of the resulting fluid.

In the past I thought that viscosity may have some primal nutritional signal in human taste. After writing this, I think it may be just correlation. When cacao butter and solids are dispersed through high heat, more of the flavor can reach the taste buds. At the same time, this same process just happens to produce viscosity.

Conclusion: use the steam wand.

Conclusion: coffee art is for coffee, chocolate art is for chocolate.