Solid + solid = liquid: Chocolate shell topping for ice cream

When I was growing up, one summer treat I really looked forward to was visits to Dairy Queen. I favoured Blizzards (to this day, I prefer ice cream with mix-ins), but I thought dipped cones were fascinating, even though I never ordered them. How did they put ice cream – upside-down, no less – into melted chocolate without turning it into a puddle?

It wasn’t until I started learning more about chocolate that I began to understand just how impressive a trick it was. The melting temperature of cocoa butter is around 34°C, about the same as a hot summer’s day. We all know just how quickly ice cream melts under those conditions.

The answer, of course, is that it isn’t chocolate… or, at least, it isn’t just chocolate. Instead, the dip is a mixture of chocolate with another type of fat (often coconut oil) that takes advantage of a phenomenon called eutectics. The melting point of a eutectic mixture is lower than that of the individual components, much like salt is used to lower the freezing point of ice in winter.

Both cocoa butter and coconut oil are solids, but when you melt them together, the resulting mixture is a liquid at (or just above) room temperature. At ice cream temperature, though, it’s a solid, which is what makes the hard shell. Because the dip’s initial temperature is so much cooler than melted chocolate, it doesn’t melt the ice cream as quickly. Plus, it’s more fluid than chocolate, which helps produce a thinner shell.

Conveniently, coconut oil is easily found at health food stores these days, so you can even make your own chocolate shell mix. With the summery weather we’ve been having lately, I decided to give it a try, using this recipe; I made the plain version, but she also offers directions for flavoured versions.

Rather than just pouring it over my ice cream, though, I assembled the tartufi shown above. (Equipment nut that I am, I can’t help but think they’d look a lot better if I had large hemispheric moulds.) Vanilla ice cream with cherry preserves in the centre, a chocolate shell and a bed of peanuts… it tastes just like a sundae!

What role did chocolate shell topping play in your childhood?

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6 Responses to “Solid + solid = liquid: Chocolate shell topping for ice cream”

  1. Dairy Queen IS a medium dipped cone. I am going to try this this weekend.

  2. Let me know how it goes, PatG!

  3. I had wanted to try the topping as part of a quiet dinner with friends. I looked for coconut oil in three or four stores without success. I finally located some in a health food store at a price that would have supplied the four of us with organic filet mignon from the butcher shop across the street. It didn’t say the oil was extracted by pressing the nuts between the thighs of virgins but at the price, I wondered.

    On Monday, I went down to an Ottawa store – The Grace which stocks Caribbean, South American and Asian foods. There I found refined coconut oil for a fraction of the price. Standard quality but if the project failed no great loss. That night I gave the oil to youngest daughter along with a package of milk chocolate chips and the recipe. We had a very nice discussion on unit conversions, the difference between volume and weight, how to set tare weight on a scale and other such kitchen fun.

    The result was amazing – just like DQ. We will be making another batch to take to a friend who has just finished chemo.

    The only downside is it is almost pure fat. Oh well small quantities on weekends only.

  4. Glad to hear you liked it, PatG! Yes, the refined coconut oil (not virgin) is the way to go, in terms of both price and flavour. Grace in Ottawa is a great store for interesting finds. And it is pretty much pure fat – though really, chocolate is never a low-fat food – but you don’t need much of it in a portion.

  5. A little update: I made a second batch and had 2oz of oil left over. I remembered I had a packet of Abuelita hot chocolate tablets left over from last winter. See:

    As it happens, 2 tablets were exactly right for 2oz of oil. The result was interesting in that the sugar stayed granular and settled to the bottom. I added a little cream and heated slightly which help dissolve some of the sugar. The result is a bittersweet chili-chocolate flavour with a hint of cinnamon. I should be great on vanilla ice cream. Next time though, I would get bittersweet chunks to start with, then add chili and cinnamon to taste.

  6. Yeah, sugar doesn’t dissolve in oil: in most chocolate, it’s just ground fine enough that your tongue can’t feel the crystals, but if there are crystals visible to the naked eye, they would just sink to the bottom of an all-oil system like magic shell. Chilli-and-cinnamon magic shell would be delicious, though!