Experiment #1: Making Vanilla Ice Cream without a Machine

In my previous post, I discussed some of the basic scientific properties of ice cream, as well as the reasons that ice cream machines make the stuff so well. Here’s a quick-and-dirty recap (you can probably skip over this if you’ve already read and mastered the material presented in my previous post):

  • Making ice cream is mostly about controlling 3 components (among others): ice crystals, air cells, and fat/sugar cells
  • Without ice crystals, your ice cream would just be liquid cream, but ice crystals that are too large result in ice cream that is super icy; ice crystals can be managed during the churning process, and machines are really good at this
  • Without air cells, your ice cream would just be a frozen block of cream; air provides insulation that keeps large ice crystals at bay
  • Fat and sugar cells not only make the ice cream delicious, but they also play a significant role in maintaining the creamy texture of ice cream by placing themselves between ice crystals

In this post, I’ll take you through my first experiment with making ice cream from scratch without a machine! Will I succeed, or will I fail: the answer to both of these questions is YES! Read on to see some pictures of the process and find out all the details.

So wait…why do you want to make ice cream by hand?

Since I started scooping ice cream at a locally-owned, gourmet ice cream shop a few weeks ago, I’ve had a strong desire to attempt to make the stuff myself. When I first started work, the whole process of making ice cream seemed so mystical – everyone was always so amazed by the quality of the product that the shop produced, always wondering how ice cream could possibly be so good. A few weeks in, I began to think that maybe I can give this a try for myself. But the major caveat is that, being broke, I don’t have any of the major kitchen tools that the shop has, such as an ice cream machine. However, I then remembered that people have been making ice cream by hand for many years, since long before the invention of the ice cream machine – so there must be plenty of information online about how to do so.

We learned in my previous post that ice cream machines are really good at controlling ice crystallization and introducing air into the mix, but how could one sufficiently do these things by hand? I decided to do some searching online about methods for making ice cream without the use of a fancy ice cream machine. The results were plentiful, so I began to sift through them to find the one or two that I thought would work best for me.

The ice cream recipe that I settled on was from an amazing cooking blog called TheKitchn. There are actually two recipes, one for making the ice cream mix, and another for making ice cream without a machine. Basically you follow the first recipe until the point where it says to “put the mix in your ice cream maker”, and then you follow the second recipe.

Finally, the time has come to actually see how I made the ice cream! Maybe after reading this, you’ll want to attempt to make your own?

Here’s how my ice cream experiment went (stepwise descriptions are below the pictures):

Please follow along with the recipes that I linked to in the previous paragraph while referring to the pictures below.

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First step in making the ice cream mix is to cook milk, eggs, sugar, and vanilla in a pot until it reaches a temperature of 170˚F.
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You’ll want to whisk this mixture constantly as it cooks. And you never want it to boil because that would cook the eggs (you don’t want solid egg pieces in your ice cream, do you?).
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Cook this initial mixture until it lightly coats the back of a wooden spoon
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Once the mixture has thickened enough to coat the back of a wooden spoon, slowly add the cream.
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Once the cream has been mixed in, pour your mixture through a fine sieve in order to filter out any solid particles in the mix.
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You’ll probably see stuff like this leftover in your sieve. This would have made for some pretty chunky ice cream. This stuff tasted a little bit like tapioca 🙂
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Now you’ll want to cool this mixture for a while in the refrigerator for 3-12 hours (I cooled mine for 12). Also the plastic wrap should be touching the surface of the mix, as this helps to prevent a undesirable layer of skin from forming.
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Once the mix has chilled for a while (I chilled mine for 12 hours in the fridge), a layer that is the consistency of loose pudding will form on top. This mix is now ready to be made into delicious ice cream.

Now, it was time to actually make the ice cream using this recipe from TheKitchn. FYI, I didn’t take many pictures of this part because the above link provides excellent pictures (next time, I will take my own though). In any case, here are some of my observations.

The Results

First off, I admittedly made a few mistakes while following this recipe.

For one thing, this recipe calls for 1 pint of ice cream mix, but the recipe I used to make the mix actually made 2 pints. So I was working with twice the amount of mix, which is theoretically twice as difficult to cool/freeze.

Second, I neglected to put salt in the ice bowl while churning the ice cream. This is because I didn’t fully understand the importance of using the salt. I have since come to learn that adding salt to ice produces a scientific phenomena called freezing-point depression, actually lowering the freezing point of ice (and making it much colder than 32ºF).

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Here’s one way to think about freezing point depression

Here’s a nifty scientific explanation of freezing point depression. In the following video, the scientist demonstrates that as you add salt to ice, the measured temperature decreases:

Essentially, by not using salt to lower the temperature of the ice cream mix, the tiny ice crystals that you want to form while you’re churning the ice cream never actually formed in my mix. After churning the ice cream in the ice bowl for the second time (after 45 mins of initial freezer-time), the recipe says that the ice cream should be the consistency of soft-serve, but mine was still totally liquid. Therefore, the lack of small ice crystal formation in this step allowed gigantic ice crystals to form when I stuck the ice cream in the freezer overnight, resulting in super icy ice cream.

What’s Next?

Even though I ended up with an overly-icy ice cream by failing to follow simple directions…

¯\_(ツ)_/¯

…I still felt that this was a very interesting learning process for me (and the ice cream was still damn-tasty). I had never even contemplated making ice cream myself before, even though I’ve loved ice cream my whole life. This has opened up a new world of possibilities for me. I now find myself waking up in the middle of the night in a cold sweat from intense dreams about whacky flavor combinations, giant ice crystal monsters, devastating vanilla bean shortages, AAAHHHH. I can’t wait to try out another recipe and do some more experimenting!

For my next ice cream experiment, I plan to make mint chocolate chip ice cream using two different approaches: steeping fresh mint leaves directly into the ice cream base vs using peppermint extract to provide the mint flavor. The ice cream world is split on these two approaches to making mint chocolate chip ice cream, so I plan on making ice cream both ways to be able to make a fair, side-by-side comparison. Which one will come out better? I have no idea, but I’ll let you know in the next post!

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