Learning about science often means learning lots of new words. Don’t worry – you can use the glossary at the end of the story to help you understand them. There, you can also find lots of cool videos and websites that are related to the story, and some fun questions to help you learn more. Happy reading!
This is Dr Maya Warren. She’s a food scientist from Missouri in the United States of America.
A food scientist is a special type of scientist, who works on producing and testing different foods. Some food scientists focus on developing new flavours or textures, while others make sure that foods are safe for humans to eat. The work of food scientists goes into every bit of manufactured food that you eat.
Maya has one of the coolest and sweetest jobs around – she’s an expert in the science of ice cream!
To you, ice cream is probably just a delicious treat; something that you eat on hot days or for dessert in restaurants. While Maya loves to eat ice cream too, she sees it as something more. Her job is to understand all the tiny chemicals that make up ice cream and what it is that makes it taste so good.
In Britain, we eat around 337 million litres of ice cream every year – that’s more than 5 litres per person! We eat ice cream at home, in cafés and restaurants, from corner shops and vans, and are lucky enough to have an incredible number of brands and flavours to choose from.
All those types of ice cream are different because of their chemistry – and that’s something that Maya finds absolutely fascinating.
Maya knows that there’s much more to making good ice cream than just putting some cream in the freezer. It’s a complicated process, with lots of steps. The key ingredients – ice crystals, fat, sugar, and air – need to be put together in a very special way.
Think about what makes the perfect ice cream. Obviously, it needs to be delicious, but that’s not all. It needs to be solid but still soft, smooth and creamy. It needs to be frozen, but not at all icy. And it needs to melt as you eat it, but not so fast that it turns to liquid. Creating the perfect ice cream is quite a balancing act! The work of scientists like Maya makes sure that your ice cream ticks all of these boxes.
To understand how to make the best ice cream possible, Maya relies on two of the most important principles in chemistry: her knowledge of states of matter (solids, liquids, and gases), and her understanding of properties.
To make the perfect ice cream, Maya needed to know how each individual ingredient affects the final mixture. The properties and state of each ingredient makes a lot of difference!
Below, there is a table from her notebook, where she keeps track of everything that she knows about each ingredient.
Using what you’ve learnt about the chemistry of ice cream, try to fill in the “State of Matter” and “Properties” columns yourself!
What Maya didn’t know, is how these ingredients differed between brands of ice cream, and what effect that had. So, she set out on a scientific mission: to compare eighteen different brands of vanilla ice cream from the USA, and find out how each brand created their ice cream mixture.
First things first: good ice cream needs good ingredients. Maya knew that the quantity and quality of the ingredients which different ice cream brands used would make big difference to the end result.
Looking across all the different ice cream brands, Maya found that there was variation in the size of ice crystals and the amount of air that was in each one. The highest quality ice creams had the smallest ice crystals and air bubbles, making them deliciously dense and creamy.
“That makes sense”, Maya thought. “If the ice crystals are too large, they’ll interfere with the ice cream’s smooth texture – you’d have to crunch them as you eat!”
Maya likes her ice cream smooth, but she found that some brands of ice cream are a little bit icy. This is because they contained more water. Ice cream with a higher water content, and lower milk or cream content, is cheaper to produce. This is perfect for budget brands, but the trade-off is that ice cream with more water has larger ice crystals.
The process of making ice cream also makes a big difference to how it looks and tastes. Maya decided to investigate the process behind making each of the eighteen ice creams, including the equipment that different companies use to make it.
Making ice cream to sell is very different to making ice cream at home. It involves huge industrial ice cream makers, which can churn out over 100 litres of ice cream per hour!
Maya noticed that ice cream was frozen much more quickly in factories than in her freezer at home. It took the industrial freezers less than 10 minutes to freeze the ice cream – super speedy! Freezing the ice cream at lightning-fast speeds means that large ice crystals don’t have time to form, keeping the overall texture smooth and silky.
She was also amazed by how quickly the mixture was churned. A constant stream of air was introduced to the barrel, making sure that all of the mixture became aerated and soft. Without this, the ice cream would be very solid and difficult to eat – hard like ice, rather than fluffy like mousse.
Maya was fascinated by how many steps were important in creating the perfect ice cream texture. Without these complex scientific processes, industrially-produced ice cream would be very different.
“So”, Maya thought, “that’s the ingredients and process covered. But what about the ice cream itself?”. She wanted to know how all of the different ice cream brands differed in taste.
It’s not enough for Maya to try all the ice creams herself – for one thing, she’d get very bored of vanilla ice cream by the end! To get meaningful results, she needed a more scientific approach.
Maya used a special kind of test, which measures the sensory attributes of food. She recruited 17 people to take the test, and each person had about 20 hours of training beforehand to make sure they were able to explain their responses clearly. Serious stuff!
The testers had to describe six properties of the ice cream they ate:
- how fast it melted in their mouth
- how much force they had to use to break up the ice cream in their mouth
- the size of ice crystals in the ice cream
- how dense it was
- how greasy it was
- its overall creaminess
They measured each of these properties with a different test. For most tests, the tester put a small cube of ice cream in their mouth, and then gave it a score based on the property they were assessing. The score ranged from 1 to 10. So, for example, if a tester was scoring “creaminess”, a score of 1 would be very icy, whereas a score of 10 would be incredibly smooth and creamy.
Maya worked hard to make sure that all of the ice cream tasting trials were fair tests. All the ice cream was vanilla-flavoured, bought at the same time, cut into cubes of the same size, and kept frozen at the same temperature. Maya kept track of what brand each one was by giving them random 3-digit numbers, which only she knew. That meant that the testers had no idea what brand each ice cream was, so they couldn’t be biased.
Each tester also tasted the same kind of ice cream multiple times, to allow Maya to assess the reliability of their responses. By repeating each taste test, Maya could see if the testers reported the same score for a particular type of ice cream over multiple trials. If they did, she could be reasonably sure that the results were reliable.
There was a large amount of variation in properties across all the tested ice creams. There are a lot of reasons why this could be, from the different types of freezer different brands used, to the way the ice cream was churned, or the quality of milk. These were factors which Maya had not been able to control, that were likely to have had an impact on the final product.
With all her results gathered, Maya was able to rank all eighteen of the ice-cream brands. She could order them by fat content, or by time taken to freeze, or even by how greasy the ice cream tasted. Whichever way she ranked them; different ice creams came out on top each time. For each aspect of ice cream, a different ice cream brand was the ‘best’.
Maya supposed that this was a good thing – we all have a favourite ice cream after all, and it’d be a shame if they were all the same.
Maya may have not been able to find an ‘overall best ice cream’, but what she had found instead was that the complicated science of ice cream making has given us an amazing variety of ice cream. All of the ice cream products she studied were unique, and each had different advantages!
And while there may be an ice cream out there for everyone, Maya knows the properties she prefers: creamy, smooth, and delicious. This research earned her a doctorate in food science, and after all that work, she definitely deserves a frozen treat!
Now, Maya works as the Head of Research and Development (also known as “Tastemaster”!) at Cold Stone Creamery, an American chain of ice cream stores. That means that she is paid to create and eat ice creams – what an amazing job!
More importantly, Maya gets to use her scientific training every day to create the best ice cream possible. She designs new flavours, creates recipes, and works hard to come up with exciting ice cream ideas that use the best quality ingredients she can find.
Maya’s love for ice cream also takes her all over the world! She’s tried tea-flavoured ice cream in Taiwan, ketchup-flavoured ice cream in Canada, and even chicken and waffle-flavoured ice cream in her home state, Missouri. Maya’s company send her to lots of different countries because they want her to experience the ice cream culture there and bring back inspiring ideas.
While Maya admits her job may have some low points – like the time she had to try garlic ice cream – she can’t think of anything she’d rather do. She’s taken her life-long loves of ice cream and chemistry, and found a career where she gets to think about both every single day!
So next time you eat an ice cream, think about Maya, and how much science has gone into your scoop.
Thank you for reading!
This story was written as part of a Masters in Science Communication project, investigating whether storytelling is an effective way to teach children about science and scientists. As a result, I would really appreciate some feedback, which you can give by answering a short survey. The survey takes less than 5 minutes to complete, and I will use the results to develop even better science stories in the future. To help, just click on the button below.
Maya’s research paper: Warren, M., Hartel, R. (2014). Structural, compositional, and sensorial properties of United States commercial ice cream products. Journal of Food Science. 79 (10): E2005-E2013.
More information about ice cream and how it’s made:
Video: Make your own ice cream (follows the same method as the Scientific American activity above)
More information about Maya and food science:
More information about states of matter:
More information about material properties:
Maya did not produce this research alone; she was supported by Dr Richard Hartel. He too deserves credit for this discovery – good science is often best done as a team.
This story would not be nearly so good without its illustrations by the wonderful Sofya Tamarina, and the advice and support of Dr. Nicola Hemmings.