A Closer Look
Lifting the Lid — Do You Know What Goes on Inside a Gelato?
Introduction
We now know that Gelato is ice cream done the Italian way, and what it takes for anything to be called Gelato with a capital G — i.e. the four cardinal virtues of Consistency, Mouthfeel, Visuals and Flavour.
But apart from being utterly delicious and gorgeous, gelato is a very complex thing. It may not seem so on the surface, but there is a lot going on ‘under the lid’ — even the plainest flavour is a combination of several substances interacting with each other, bonded together through different means, and cohabiting in different physical states.
In order to achieve predictable (in other words consistently delicious) results, we have to know what goes on inside Gelato. Of course you could just follow recipes and still make great creams. But if you want to go one step further and come up with your own creations, you will give yourself a great head-start if you understand these interactions.
This article will get you initiated in just that.
Read on!
Breaking Down
One of the great learnings from doing even the most elemental science is that it is possible to understand most things in the world a little better by breaking them down into parts (thankfully my two year-old didn't get to that stage yet!)
So in order to figure out how it is that Italians achieve the four cardinal virtues through artisan means, we could do well to have a closer look at a Gelato's constituent parts.
One cool thing about breaking things apart is that we can do it from different perspectives.
Say you have a toy car like my two year-old's fledging Lightning McQueen model. You can say it has four wheels, one engine, four exhausts, two (fake) head-lights, two rear-lights, etc. — and so break it down by its constituent mechanical parts.
But you could also say that it has a red bonnet, four black tyres, two yellow lightening bolts on the sides, etc. — now breaking it down by colours.
We will do the same with Gelato and, in this article, will break it down based on:
- Physical states
- Structure
- Ingredient groups
Hopefully, at the end of the article we will have a solid overview of what goes on under the hood and in the paddock, in order to come up with our own take on the dessert of the Gods.
Let's get started!
The Physical States
When you look at a Gelato you think of it as a cream: something cold, foamy — neither solid nor liquid — and, well, irresistible. The cold and delicious parts are correct, the neither solid nor liquid not so much.
Because you see, Gelato is such an amazing product that it actually contains elements in the three physical states that we can experience in our daily life (i.e. solid, liquid, and gas) at the same time.
I will dig a little deeper into the nuts and bolts of how this works in a future article. For now though, all I want is that you keep in mind that a Gelato will always contain the following:
- Water: It may sound counter-intuitive, but your Gelato will always contain liquid water, which works as the 'gel' binding everything else together. By the way, water is the most abundant element in a Gelato, usually ranging between 60 and 70% of the total weight.
- Air: You may not notice it, but there is a lot of air in your Gelato too — in fact anything between 25 and 40% of it. It is the cushion that will help create that soft, pliable consistency we all crave for;
- Solids: Everything else in a Gelato will be solids. They are the elements that will give its distinctive characteristics (flavour, aroma, colour and nutrients). Notice however, that some of the water in your Gelato will also be frozen solid.
It goes without saying, but I would like to remind you anyway, that solids can't freeze (since freezing means going from a liquid state to a solid one). This is an important thing to take note because it will have implications for when we are making our Gelato.
You might also be wondering how can it be that a Gelato contains both liquid and frozen water. I explain how this is possible in this article if you are curious, but essentially, not all water freezes at once in a complex system. And it is precisely due to the tension between frozen and liquid water (i.e. more frozen water = harder consistency) plus the cushioning from the air bubbles that the part-frozen creamy structure of a Gelato is achieved.
If it's still not clear, just have a look at the image above. It should help visualise how the elements are distributed in a mix. Finding the goldilocks balance between them while developing our recipe is one of the steps to achieve that legendary consistency that we want.
Understood? Great, we can now come to our first conclusion:
Gelato is born from the interplay between Air, Water and Solids. Take one of them out and there can be no Gelato.
Let's move on!
Structure
I mentioned above that solids dispersed in water are what gives our Gelato its distinctive characteristics. But do all solids work the same? The answer, as you can imagine, is no. Different solids will interact with water in different ways, each producing a different result.
Understanding how these interactions take place is crucial to enable us to actively control their outcome. We could write a book on the topic (actually there are many of them), but for this introductory article we will stick to the basics:
Mixtures
When we dissolve a substance in another we are creating a mixture. Mixtures can be homogeneous and heterogeneous. In a homogeneous mixture you can't tell the substances apart and they behave as if they were one (think sugar in water). In a heterogeneous mixture you can, and they will usually separate if left alone (think oil in water).
Solutions
There is only one type of homogeneous mixture and it is called a solution. The key thing about solutions is that the different substances bind together and cannot be taken apart through mechanical means (i.e. filtering).
Colloids, Emulsions, Suspensions
As for heterogeneous mixtures, they come in different types, depending on the size and state of the particles. So when the particles in a mixture are really really tiny, so tiny that you can't tell them apart, and they won't separate spontaneously, you have a colloid (think of milk). If the mixture is made of two liquid substances which normally don’t mix together but are mixed in a way that they won't separate, you have an emulsion (think of mayonnaise). And if it is made of bigger particles which may settle and are visible by the naked eye, you have a suspension (think of muddy water).
Now, if you have been thinking about what I just said and what goes into a Gelato (milk, cream, sugar…) and what they are composed of (water, fat, proteins…) you are probably coming to the conclusion that a Gelato is in fact a mixture — right?
Well done!
But you probably also noticed that in a Gelato you have mixtures of water (from the milk) and sugar; water and fat; water and proteins. And these substances yield different types of mixtures — right?
Right!
Amazed? I got more…
Foams
Let's not forget that in the middle of all these mixtures we will also throw in air bubbles (remember, there is no Gelato without air, water and solids). And when you trap pockets (i.e. bubbles) of air into a liquid or solid, you get what we call a foam.
I don't know about you, but I find all this amazing. Think about it — what this all means is that:
A Gelato is, at the same time, the four types of chemical mixtures — solution, colloid, emulsion and suspension — and also a foam.
Utterly pleasant on the outside (to the eye, the nose, and the palate), yet wildly complex within. How is that for a fantastic product?!
Now you tell me what is not to love in Gelato :)
Grouping Solid Ingredients
Now that we have an overview of what happens at a macro level within a Gelato, it’s time to have a closer look at the solids in a recipe.
Comprising everything in a cream that is neither air nor liquid water, the solids in a recipe are what effectively allows us to create different flavours, with their unique textures, colours and aromas.
Any ingredient that is not water or air will contain solids, and since Gelato is a food (an utterly delicious one at that, but still food), we will group the solids in a recipe in a way similar to nutritionists.
Unlike nutritionists though, we will focus on the function each of these group performs in our Gelato, instead of their nutritional value. In broad lines, every single ingredient that we add to our recipe will be broken down into the following groups:
1. Sugars: These are carbohydrates of the mono and disaccharide type, meaning they are composed of either one or two carbohydrate molecules bound together. There are several types of sugar, each with their individual characteristics. The one we normally refer to as table sugar is actually called Sucrose and is a disaccharide (i.e. it contains two carbohydrate molecules joined together due to condensation reaction). Other types are Fructose (a monosaccharide found in fruit) and Lactose (a disaccharide found in milk).
Sugars are crucial for Gelato-making, because they perform a number of functions. First and foremost they confer sweetness, but that’s not all. They are also responsible for lowering the freezing point of water and, by interacting with water molecules, helping produce a smoother texture.
2. Fats: These are complex molecules present in foods and can be found in ingredients of animal or vegetal origin (i.e. milk, cream, nuts, chocolate). In terms of nutrition, they provide energy (being the nutrients with the highest caloric index), but in a Gelato they do much more: because of their characteristics, fats are great carriers for other nutrients, which attach to them; they are responsible for creating the perception of creaminess; and they help enhance the perception of flavour in the mouth.
So not as crucial as sugars but a really nice add-on.
3. Proteins: The third type of so-called macro nutrient, proteins are the building blocks of cells. Being also complex molecules, they have a special characteristic — they tend to fold under certain circumstances. This comes in very handy for Gelato-making, because it makes them interact with fat globules, ice crystals and air bubbles in a way that helps creating a smoother texture which makes our tongues and palates really happy.
Like fats, not as crucial as sugars, but damn you want to have them in your Gelato!
4. Other solids: everything that is not sugar, fat, or protein, for Gelato-making purposes is classed as other solids. These can be: complex carbohydrates (i.e. polyols, alcohols, starches, fibre); minerals; salts; vitamins; you name it. Because it is a large group, their functions are varied. Salts make things salty but also lowers the frezing point of water; starches and fibres provide bulk, elasticity and volume; polyols provide sweetness and lower the freezing point of water.
Each of them is thus considered according to their function when working on the recipe.
But there is one particular type of other solids that is worth looking into in a little more detail. We will discuss them deep and wide in a future article, but they are so important for Gelato-making that we will ceremoniously introduce them now: Stabilisers. These are complex carbohydrate chains that interact with water molecules in a way that, well, stabilises a mixture. A classic example is corn starch: add it to water, heat it, and voilà, you have a tasteless, neutral coloured, thick homogeneous cream.
This cream (which happens to be a colloid) is the result of the stabiliser behaving a bit like a mesh holding other molecules into place, which brings great improvements in terms of consistency, melting and mouthfeel.
In sum, other solids are what makes Gelato delicious. Take them out and you have no flavours, no aromas, no volume and a pretty flat texture — and I don’t know about you but for me, nothing really worthy of tasting :)
So there you go, now you have an idea of what we mean by solids in a recipe, and how they allow us to assess how an ingredient will affect the final product.
As an example, take milk. White and homogeneous to the naked eye, it is actually a mixture containing fat, sugar (lactose), proteins and mineral salts diluted or suspended in water, at a specific proportion.
As the saying goes,
There is more to solids than meets the eye…
Connecting the Dots
At this stage you might be satisfied that you learned some interesting stuff but asking “how will all this help me with Gelato-making?”
And that is a very good question, with a very straight-forward answer:
In order to achieve the four cardinal Gelato virtues of Consistency, Mouthfeel, Visuals and Flavour, we will have to get the perfect balance of the elements (air, water and solids); combine our ingredients in a complex yet harmonious mixture that is at once a solution, a colloid, an emulsion and a suspension; and make sure that we have the right proportions of different solids.
I hope you get the picture. In an upcoming post in this series we will look into the effect each of them has in our Gelato, but for now, it is enough that you are aware of them.
Well done so far!
Wrapping Up
So there you go, we now know that underneath its veneer of simplicity, Gelato is an incredibly complex product that:
- Is composed of the three physical states: air, liquid water, and solids.
- Incorporates simultaneously the four types of chemical mixtures — solution, colloid, emulsion and suspension — and is also a foam.
- Contains solids that provide its taste, aroma and colour. These are grouped for practical purposes according to their function as: sugars, fats, proteins, and other solids.
- When carefully balanced so that the proportion between the different physical states, the different mixtures and the different solids groups is just right, can be produced in a consistent, predictable manner using a wide range of ingredients.
A presto!!
*Note: this story is part of a series of articles comprising an introduction to Gelato-making. You can access the full series here:
