See the German-language version of this pieceatSpektrum der Wissenschaft.
People have been enjoying ice cream for hundreds of years.
But there have never before been as many flavors as we enjoy these days. From sweet to savory, the ice’s cream wondrous variety is all due to chemistry.
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Ice cream is a heterogeneous mixture of a liquid and finely dispersed solids. That is why it is called a complex colloidal system.
Each part in this system has an important function. Air bubbles typically make up about 30 to 50 percent of the mixture’s final volume. They alleviate the feeling of cold and provide suppleness.
If the air content is too low, the ice cream becomes hard. If it is too high, the treat becomes too frothy and loses its taste.
Fat droplets make ice cream creamy. Proteins from milk form around the fat, a combination that helps to separate the droplets and stabilize the mixture.
Liquid sugars surround the insoluble particles. They determine sweetness and softness. In food science, the sweetness is recorded using a scale called “potere dolcificante” (“sweetening power”), or POD. That part of sugar’s contribution is obvious.
Less obvious is the fact that sugar lowers the freezing point of water, reducing the amount of ice that forms in the mixture. It therefore has “antifreezing power,” which is also called “potere anticongelante,” or PAC.
The sugar sucrose sets the standard for PAC, which corresponds to how much the freezing point is depressed by, say, one pound of sucrose dissolved in 100 pounds of water. Ice cream manufacturers use many more sugars. The lower the serving temperature, the more sugar is needed for creamy ice cream.
Professionally produced ice cream has a serving temperature of 12.2 degrees Fahrenheit. This corresponds to a PAC value of approximately 270.
In gastronomy, the serving temperature of ice cream drops to 1.4 degrees Fahrenheit,so the PAC value must be higher to get the perfect softness. The recommended PAC is between 400 and 420, which essentially affects the sugar content.
For 2.5 pounds of ice cream, we recommend this recipe. The result is a PAC of 390 and a POD of 320 at serving temperature.
But there is more than just sugar, fat, ice and air in your scoops. In addition, there are neutral components, such as emulsifiers and stabilizers. They bind solid components or fats with water and thus influence the consistency.
Locust bean gum and xanthan gum are most commonly used. The latter is obtained during the fermentation of sugar-containing substrates and serves as a thickening and gelling agent.
For a long time, the ice cream industry expanded the palette of flavors. Now the focus is on less caloric and less sweet concoctions. To achieve this, sugars are replaced with polyols, and fats are replaced with inulins.
The production of these new ice cream varieties is limited so far, but it is expected that they will soon become established.
This means maximum joy!
FAQs
Ice cream is an emulsion—a combination of two liquids that don't normally mix together. Instead, one of the liquids is dispersed throughout the other. In ice cream, liquid particles of fat—called fat globules—are spread throughout a mixture of water, sugar, and ice, along with air bubbles (Fig.
How is science involved in ice cream? ›
If the air content is too low, the ice cream becomes hard. If it is too high, the treat becomes too frothy and loses its taste. Fat droplets make ice cream creamy. Proteins from milk form around the fat, a combination that helps to separate the droplets and stabilize the mixture.
What is the science behind creamy ice cream? ›
Air bubbles make ice cream soft and creamy. A large number of small air bubbles make ice cream smoother. Overrun is the amount of air included in ice cream and the percentage it increases the volume. Adding more air can make ice cream smoother, but it can also increase the size of the ice crystals.
What is the science behind melting ice cream? ›
TL;DR. Ice cream contains tiny ice crystals that are surrounded by air cells and fat globules. As temperatures rise, these ice crystals melt and the structure is destabilized, which we call melting. The warmer the temperature, the more quickly the ice crystals melt, and the more melting we see.
What is the science behind churning ice cream? ›
Ice cream makers (commercial or for home use) ensure small ice crystals by agitating or beating the liquid as it freezes. This keeps the water molecules moving and prevents the crystals from growing larger. The mixing process also incorporates air, which is the secret ingredient to give ice cream a lighter texture.
How is ice related to science? ›
The water molecule
Ice is the solid state of water, a normally liquid substance that freezes to the solid state at temperatures of 0 °C (32 °F) or lower and expands to the gaseous state at temperatures of 100 °C (212 °F) or higher.
What makes ice cream thick? ›
Egg Yolks: The most traditional thickening agent, egg yolks contain natural proteins and fats that contribute to a rich and luxurious texture in custard-based ice creams. Cornstarch: Often used in non-custard ice creams, cornstarch mixed with milk helps thicken the base and create a smooth mouthfeel.
What makes ice cream creamy and not icy? ›
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.
What is the secret to making ice cream very creamy? ›
As you churn ice cream, individual water molecules turn into ice-crystal seeds — which is what makes cream freeze. The higher the fat content, the more time you have to churn before these ice crystals congregate, resulting in creamier final texture.
Why does ice cream not freeze? ›
As the ice cream mixture is cooled down, some of the water freezes and forms ice crystals. The concentration of sugar increases in the rest of the water, lowering the freezing point of the sugar-water solution – just like the salt in the example above. As a result, the ice cream stays soft.
Similar to sugar, salt affects how water freezes and effectively lowers the freezing/melting point of water. Creating a saltwater slush and packing this around our ice cream base allows us to cool the base enough so that it starts to thicken and freeze before the ice melts completely.
Does sugar make ice cream freeze faster? ›
answer is that the more sugar added and dissolved into the cream base, the longer it takes to freeze. Sure, the ice cream will take more time, but it's for a good reason — you'll get a smoother, creamier scoop. Careful, though — excess sugar can have a negative effect; add too much and the ice cream won't set at all.
Does ice cream expire? ›
Ice cream does go bad, and it can make you sick. Now technically, ice cream will be safe to eat for up to three or four months. Note that we said ice cream would stay fresh for six weeks, not just edible. After the six-week marker, ice cream begins to lose its optimal taste.
What gives ice cream its creamy texture? ›
At its core ice cream is a successful emulsion of fat into water, sugar, and ice with air mixed into the batch. An emulsion is a mixture of two substances that typically separate (like oil and water). But, instead mix together to form the consistent creamy base used for ice cream. It's Science!
What makes commercial ice cream so creamy? ›
Simply put, stabilizers help keep commercial ice cream creamy-tasting under variable temperature conditions. If you're making ice cream at home, there are a few things you can do to encourage a creamy texture without stabilizers.
What scientific principle is used in the freezing of ice cream? ›
The decrease in freezing point that happens when salt is added to water is called freezing point depression. Pure water freezes at 0° Celsius (C), but water mixed with salt freezes at less than 0° C. Freezing point depression is not unique to water and salt; it happens with all solutions.
What is the science behind why we love ice cream? ›
Our earliest ancestors passed down that evolutionary sugar craving — researchers can actually see our brains rewarding us with the feel-good chemical dopamine when we eat ice cream. Eating sugar also cuts down on stress-inducing chemicals. That rich, creamy fat also works overtime in your mouth.
What is the science behind ice freezing? ›
Freezing is the process that causes a substance to change from a liquid to a solid. Freezing occurs when the molecules of a liquid slow down enough that their attractions cause them to arrange themselves into fixed positions as a solid.
What is the science behind dry ice ice cream? ›
This type of phase change is called sublimation, and we are going to put this phase change to work as a tool to perform rapid heat transfer. In this method, crushed dry ice very rapidly transfers the heat energy from the liquid ice cream base into the surrounding atmosphere as its phase changes from a solid to a gas.
