Learn the science behind:
Sometimes, I just want to share a recipe. No extensive science, just the food, just to make sure I store the recipe somewhere so I can make it again (I have a tendency to lose recipes I find online, for my cookbooks I have a Post-It system that makes me remember recipes, but digitally things just get lost). This post started out that way. The coffee chocolate caramel ice cream tasted so good I just had to share it.
But then, I noticed there’s more science to this ice cream than I realized. Adding chocolate chips to ice cream is not as straightforward as it, that is, if you don’t want to break your teeth when eating this ice cream!
Adjusting inclusions for ice cream
I’ve made ice cream before on this blog, both with and without eggs and I’ve writte about the science of ice cream (more specifically freezing point depression). This time however it’s not the ice cream itself that’s special or ‘scientific’. Instead, it’s the extra inclusions in the ice cream: the caramel & especially the chocolate.
Both the caramel and the chocolate are only mixed in at the end of ice cream making, after the ice cream comes out the churner, or after it has been frozen mid way. Since we’re mixing these into something cold and partly frozen and since we’ll be eating these frozen, we’ll have to make sure the caramel and chocolate are palatable when frozen!
Inclusion 1: Caramel
We’ve discussed what happens to caramel upon freezing before. Caramel contains a lot of sugar and as we know, adding sugar will lower the freezing point of the sugar + water mixture. This makes the caramel softer at lower temperatures. Using a caramel in an ice cream will thereforo not tend to give any problems. It will tend to stay soft enough (sometimes even too soft and sticky) to still eat well.
Inclusion 2: Chocolate
Chocolate is a different story though. Chocolate consists of sugar, cocoa powder and mostly fats (cocoa butter). These fats are liquid at body temperature (which is why chocolate melts in your mouth) and solid at room temperature (20°C). However, even at room temperature not all fats are solid, some are still soft. Upon cooling the chocolate, more and more fats will solidify. As a result, the chocolate becomes harder.
Did you ever place chocolate in a fridge? You probably noticed it became a lot harder. Now imagine freezing a solid chocolate to -18°C. It will become even harder and if large chunks are used, it might be impossible to bite through. When mixing in this chocolate in an ice cream, it’s an important question to ponder upon a little.
Making chocolate suitable for ice cream
Thus we have to find a way to make chocolate softer in ice cream. There are roughly three ways to do this:
- Change the recipe of the chocolate: you will see this being used by food manufacturers. Adding more fats or softer fats (e.g. milk fat or certain vegetable fats) will soften the chocolate.
- Change the size & shape of the chocolate: a large chunk of chocolate will always be harder to bite through than a thin strip of chocolate. It’s for a reason that Magnum ice cream only have a thin chocolate outer layer!
- Soften chocolate by changing the processing: the way chocolate is processed influences the hardness of chocolate, for this we have to dive a little deeper into the concept of ‘tempering’ chocolate.
As mentioned, chocolate contains a significant amount of fats, mostly cocoa butter fats. These fats can solidify in various crystal types in the chocolate. When making a chocolate bar you’re looking for one specific crystal type. This chocolate type will make the bar very glossy and give it a snap. Without the crystal type the chocolate tends to be softer, not glossy and it will create so called ‘bloom’ (white marks) on the chocolate.
Chocolate is tempered by properly controlling the temperature of the chocolate since the desired fat crystals are formed at a specific temperature range. By not doing this proper temperature control we can create those normally undesired crystals. But in ice cream we might want them since they make the chocolate softer!
Making chocolate for adding into ice cream
As a home chef it’s hard to adjust the recipe of your chocolate, so options 2 and 3 are more common. In the ice cream mentioned below, we’ve used a combination of the two to make a good chocolate inclusion. We’ll discuss two methods. Both involve getting rid of the temper of chocolate by melting the chocolate (thus removing all those stable crystals) and cooling it uncontrolled (or at least such that not the good crystals are formed). The way the chocolate is ‘shaped’ differs.
Method 1: Melt & cool into pieces
Melt the chocolate completely (for example, in a micro wave, 30s at a time, mixing in between) and spread out on a countertop or parchment paper. Leave to cool. You will notice it will take quite a while and it will never become very snappy. Break the chocolate in small pieces and mix in with the freshly made ice cream.
This method will give you control over the size of your chocolate pieces and how they’re mixed in.
Method 2: Melt & pour
Melt the chocolate completely (same as you’ve done above) and pour the liquid chocolate into the ice cream just before putting it in the freezer. If you’ve churned your ice cream, it will be cold and the chocolate will become solid pretty much immediately. If your ice cream mixture is still warm though, you run the risk of not making chips, but making a chocolate ice cream with chocolate everywhere.
Coffee chocolate caramel ice cream
So now that we know how to make chocolate pieces for your ice cream, it’s time to use it. In the ice cream below method 1 was used to make the chocolate ‘chips’. It gave a great snappy texture and the chocolate broke easily upon eating.
The recipe I used as a starting point came from the blog by David Lebovitz. The original recipe is inspired on a Mexican ice cream, mine is again inspired by that one, but changed about a little more.