If there is one dessert that says “summer,” that dessert is (obviously) ice cream. And if you want to up the ante even more on the summertime-y-ness, make that homemade ice cream. Fresh-churned ice cream—strawberry, vanilla, peach, chocolate, or anything else—is a delicious and celebratory treat. Unfortunately, it is a treat that is far too rare. Much like the Thanksgiving turkey, homemade ice cream is often made only once per year by many people, and that on the Fourth of July. I see no reason why this should be the case. Yes, ice cream for the Fourth is amazing and right and proper, but why not for the fifth of July? The 13th? August first? Thanksgiving?

I think part of the reason we don’t make it at home as much is that it’s a little intimidating. It makes sense; we’ve all had homemade ice cream that was subpar—either runny or icy. But maybe if we all practiced more, our ice cream would be better. Of course, along with practice, we could use temperatures to help us make the best possible ice cream. Let’s take a look at how that works! And since we’re after the best ice cream, we’ll use a recipe from Rose Levy Beranbaum’s mouth-watering book Rose’s Ice Cream Bliss.

Ice cream: textures, ingredients, and temperatures

If we want a smooth, creamy ice cream—as opposed to a coarse, icy one—we need to take care with the ingredients and the temperatures.

Smooth, creamy ice cream is the result of having very small ice crystals that are kept apart. We’ll talk later about how to get small crystals, but first, let’s look at how we can keep those crystals from interacting with each other. This is accomplished mostly with our ingredients.

Harold McGee talks about ice cream texture and how it is a combination of ice crystals, concentrated cream, and air:

The ice crystals form from water molecules as the mix freezes, and give ice cream its solidity; they’re its backbone. And their size determines whether it is fine and smooth or coarse and grainy. But they account for only a fraction of its volume.

The concentrated cream is what is left of the mix when the ice crystals form. Thanks to all the dissolved sugar, about a fifth of the water in the mix remains unfrozen even at 0°F/-18°C. The result is a very thick fluid that’s about equal portions of liquid water, milk fat, milk proteins, and sugar. This fluid coats each of the many millions of ice crystals, and sticks them together—but not too strongly.

—Harold McGee, On Food and Cooking, pg. 40

To get rich ice cream, you need enough fat, enough milk protein, and enough sugar to keep the water in the ice cream from freezing solid. The super-premium brands of ice cream that you know and love from the store have about 16–20% milk fat, as opposed to only 12–14% for standard name brands. The standard name brands have a higher percentage of other milk solids than do the premium brands, which means they have more milk than cream.

Another ingredient that will deliver smoother, richer ice cream is egg yolks. Again, McGee:

The proteins and emulsifiers in egg yolk can help keep ice crystals small and the texture smooth even at relatively low milk-fat and high water levels[…] A mix that contains yolks must be cooked to disperse the proteins and emulsifiers (and kill any bacteria in the raw yolks), and the resulting thickened, custard-like mix makes an ice cream with a characteristic cooked, eggy flavor.

McGee, On Food and Cooking

In fact, most of the best ice cream is made with eggs and is, thus, technically frozen custard.
But putting egg yolks in a pan and cooking them with milk and/or cream is a recipe for weird chocolate scrambled eggs—not ice cream—if you overcook it. Enter Thermapen^® ONE and our first critical temperature!

According to Rose Levy Beranbaum, the egg mixture needs to be cooked to between 170°F and 180°F (77°C and 82°C). Using a fast and accurate instant-read thermometer like Thermapen ONE ensures that you hit the temperature mark right on the head. A few degrees too cool and you won’t get the thickening power you want, a few degrees too hot and it will curdle. Hitting it right down the middle wins the day.

Dealing with “ice” in ice cream

So much for the ingredients, now let’s turn to the “ice” of good ice cream. The smoothness of ice cream is in large part an inverse function of the size of the ice crystals in it. Small crystals are harder to detect with the tongue and therefore give you a smoother feel. We can achieve smaller crystals in two ways: agitation and cooling speed.

By moving the ice cream as it cools, the ice crystals get tumbled against each other like rocks rolling in the surf, polishing their rough edges. All modern ice cream machines incorporate some kind of dasher to move, flip, and shuffle the ice cream as it cools and congeals, thus keeping the crystals from growing into large ice shards.

(Those dashers also incorporate air as the ice cream dances around, making it lighter, fluffier. The amount that ice cream increases in volume as it freezes is called “overrun.” Premium ice creams have less overrun, and gelato is made with machines that produce the least overrun of all, giving it its characteristic dense texture.)

Then, of course, there is cooling speed. The longer it takes the ice cream base to freeze, the larger the crystals will be. We want maximum chill for smoother ice cream. (In fact, using liquid nitrogen to freeze your ice cream produces a finished product of exceptional smoothness!) If you have a frozen-bowl ice cream maker, make sure it is well frozen before you begin churning.

Chill before you churn

That need for a quick phase transition is one reason why it is very important that you chill your ice cream base before you churn it. I know it’s a bother, but getting the base down below 43°F (6°C) or lower—a temperature verified with your Thermapen—is essential, especially if you have a frozen-bowl ice cream machine. Those things can only suck so much heat out of your ice cream before they stop cooling, so you need to start much closer to freezing.

If you want to speed up the chill process, you can certainly use an ice bath. Set your bowl or pot of ice cream base in a much larger bowl of ice and water, and stir it as it cools. You can use your Thermapen to monitor the temp as you go so you know when you get to a low enough temperature. Just make sure that as you stir the ice cream you don’t agitate the water so much that it splashes up into the bowl with your base!

Freezing after churning

The motor on any given ice cream churn just can’t handle plowing through a finished product that is properly scoopable. Anyone who has worked at a scoop counter will tell you that ice cream doesn’t love moving! In order to get to the sit-on-a-cone consistency, you need to freeze the ice cream further. I know this kills some of the joy of it, but you really should make ice cream yesterday to eat it today, otherwise it will only be as thick as a good milkshake, at best.

As soon as it is churned to the proper thickness, move it to your freezer, covered with parchment or plastic wrap right on the surface so that it doesn’t develop a skin. Let it sit for several hours (overnight is best) before serving, and you’ll get that real scoop-shop texture that is classic “ice cream.”