Learn the science behind:
Light brown, or almost black. Runny and oozy, or firm and chewy. Sweet, slightly salty, or with a hint of bitterness. Caramel comes in all shapes and sizes. You can easily tweak it to your liking, once you understand how it works. So let’s investigate the science of caramels!
You can make caramels with just a few simple ingredients and a stovetop. But, caramels can be finicky. They can crystallize when you don’t want to. Or, turn too hard – or soft. Luckily, most of these problems can be solved with some easy fixes, once you know what to do.
- What is caramel?
- How to make caramel
- Troubleshooting caramel
What is caramel?
That is a good question. What does make something a caramel? There isn’t a clear set definition for caramel, unlike there is for other confectionery such as chocolate. For instance, technically speaking, you could refer to dulce de leche as being caramel.
Others may refer to it as caramel candy, we’ll stick with caramel. It’s a sweet treat, you can eat them in individual pieces. Or, the caramel may be part of a bigger dish.
Here we’ll refer to caramel as a sweet type of candy, with sugar (or a sugar replacer) as its core ingredient. Common other ingredients are milk – plant- or animal-based, butter, margarine, cream, salt, and water. Also, the caramels we’re discussing have a color somewhere in between a light orange and a dark brown. Caramels are sweet but can have a complex flavor. Some are creamy, others grainy, whereas again others can be stretched long distances.
Caramels can be liquid and poured. In that case, you’d probably refer to them as caramel sauce. Since you might run into some specific challenges when making a pourable caramel, we’ve dedicated a separate post to the topic. That said, the core science discussed in this article still applies to most sauces.
Caramel color is an additive that manufacturers may add to foods to turn them (dark) brown. You can simulate making caramel colors on a small scale. Read how in our article on controlling color and flavor of sugar syrups.
How to make caramel
In its simplest form, you can make a caramel by heating the ingredients on the stovetop and subsequently cooling them down. However, most caramel recipes are slightly more complex, e.g. they might contain two different heating steps. We will discuss one of those, a caramel made through two subsequent heating steps (see also the recipe at the bottom of this article).
So why even have two heating steps?
To explain, we need to look at what you’re trying to achieve when making caramels. There are two things:
- Develop the flavor and color of caramel
- Create the correct consistency, e.g. firm, chewy, or slightly soft
You can influence both the flavor and color, as well as the consistency by choosing your ingredients wisely. But, the process you use has a big impact as well. When you’re using a two-step process, often that first step focuses on developing the flavor and color, whereas the second step determines the consistency.
Step 1: Developing the brown color
Unless you’re using brown sugar to make caramel, the ingredients you have at hand, are likely quite bland. Regular sugar, cream, milks, fats, they’re all white, or versions of off-white. However, you want your caramel to be brownish at least. What’s more, these ingredients are relatively bland in flavor. Mix these, and you’d mostly be left with a (very) sweet treat, due to all the sugar.
Without adding any extra ingredients, you can develop a lot of color and flavor for your caramel. All you need is heat!
Caramelizing sugar can add color & flavor
The first way to add color and flavor to a caramel is by caramelizing the sugar. When sugar is hot enough, it will start to turn brown and change flavor. This is called caramelization. Regular sugar, which consists of the molecule sucrose, starts to caramelize at about 160°C (320°F). At even high temperatures, it will only turn darker and more bitter, until it burns.
To caramelize sugar you have to heat just the sugar, maybe with some additional water. Adding almost any other ingredient will cause it to burn prematurely.
Caramel recipes using this ‘trick’ to add flavor and color therefore often start by caramelizing just sugar. Once the sugar has develop the color or flavor you need, cool it back down by adding some of the other ingredients, e.g. milk or cream into the sugar. If you don’t add any other ingredients, the sugar will continue to caramelize for a bit, even after the heat is turned off. So, add this in quickly.
The Maillard reaction is a faster, less hot, option
There is another way to develop color and flaovr, that doesn’t involve as high heats. It is through another very common chemical reaction in food: the Maillard reaction. During this reaction brown colors and plenty of flavor molecules are formed as well.
The Maillard reaction requires both proteins and sugars to occur and will happen at temperatures well below those of caramelization. It’s why you can’t heat a mix of sugar and milk as hot as just sugar. The proteins in the milk will react with the sugar and turn the mix brown, long before caramelization sets in.
Often a recipe might call for cooking all the sugar with some of the protein-containing ingredients until a nice brown color is reached. Then, other ingredients are added to cool it back down.
Or just add brown sugar
If your caramel recipe only consists of one step, there’s a good chance you need to add brown sugar. You can create a brown caramel without caramelizing sugar, or significantly triggering the Maillard reaction. Brown sugar contains molasses. This has a very dark, deep color that can color your caramel.
However, these caramels might lack some of the complexity in flavor. Both during the Maillard reaction as well as caramelization, a lot of flavor molecules are formed. These can help offset the just sweet flavor of a caramel.
Step 2: Controlling caramel consistency
After this initial heating step, most caramel processes contain a second step. During this step the mix doesn’t become as hot, but it may be reheated again. It’s at this stage that the texture and consistency of caramel are determined.
So how does that work?
The concentration of sugar impacts texture
Let’s have a look at sugar again. Sugar and water have some pretty special interactions. First off, you can dissolve a lot of sugar in water. The warmer the water, the more sugar can be dissolved within. When you’ve truly dissolved a lot of sugar in the water, the sugar solution will start to behave differently.
At first, it will just be thicker. If you pour it, you will notice it’s a bit more like honey than pure water. The more concentrated the sugar solution, the thicker it becomes. At some point you can literally ‘pull’ the solution. Concentrate it even further and it literally becomes as hard as glass.
Removing just enough water
After the first heating step you’re often told to add back in cream, milk, or butter. All of these ingredients cool down the sugar, but they also dilute it, by adding in moisture. As a result, the caramel becomes thinner again. By bringing it back to the boil, you can evaporate moisture, to increase the concentration again. The longer you boil, the thicker and thus harder the caramel becomes.
Make a softer caramel by adding more moisture. Make a harder caramel by cooking off more moisture (or adding less back in).
Recipes often call for measuring the temperature at this point. The temperature of a boiling sugar solution is a good measure for the concentration and thus consistency of the solution. Try to stick to temperatures given in instructions. It will help you achieve the correct texture. If you do think the caramel is too soft, simply cook it to a higher temperature next time. If it’s too hard, decrease the target temperature next time around.
Caramel may sound simple. Heat some sugar, to turn it brown. Then whisk in a few other ingredients to get the texture you’re after. Unfortunately, caramel has a tendency to not behave as desired. It might develop crystals on top, be too soft, turn grainy, or even separate. Luckily, there’s a way to fix (or prevent) most of these! Let’s have a look.
How to fix crystallized caramel?
Fixing crystallized sugar during caramelization
Your caramel can crystallize at two different points in time. First of all, it can do so when you try to caramelize it. It’s actually quite common. If it happens, just add a little extra water, redissolve the sugar and continue going.
Fixing crystalline caramel
But, your caramel can also crystallize after you’ve made it. Maybe a thin white layer has formed on top? If you’d look closely at this white layer, you will see tiny crystals. As little water easily dissolves these crystals since they’re sugar crystals.
Unfortunately, once your caramel has started to crystallize there is not much you can do without reheating it. Fortunately, crystallized caramel is perfectly fine to eat.
Preventing crystallized caramel
You can prevent sugar from crystallizing a next time. Again, to explain, we need to have a closer look at sugar. Sugar, or more specifically, sucrose loves to crystallize. If there’s not enough water, it will crystallize. To prevent it from crystallizing in your caramel you have a few options:
- Add a crystallization inhibitor. This is an ingredient that prevents, or slows down the crystallization of sugar. The most common one? Corn syrup! Corn syrup contains a lot of large long molecules that interfer with sugar molecules finding each other and forming a crystal.
- Break down some of the sugar. Sucrose is the one that’s crystallizing. If you break down some of the sugar into invert sugar, you can prevent crystallization. You can do so by adding a little acid to sugar while you’re cooking it.
Fixing a grainy caramel
A grainy caramel has turned grainy due to the crystallization of sugars. The only way to truly fix it is by reheating the caramel to redissolve the sugars. If that’s not an option, make a new batch, focusing on preventing it from happening next time.
To prevent a grainy caramel, follow the same steps as above. Add some extra crystallization inhibitors and control the moisture well.
How to fix a separated caramel
A caramel can split if there’s fat in the caramel (e.g. from butter or cream). Often, a split caramel can be saved by gently reheating the caramel and stirring continuously. Adding some extra water can also help here to mix everything again before boiling off that extra water one more time. Last but not least, do not heat or cool down the caramel too rapidly. The fat might melt or solidify at a different rate than the caramel, causing the split.
Why caramel becomes (too) hard
No worries here! Just add some extra moisture, reheat and you will turn out with a thinner and softer caramel.
Can you freeze caramel?
Yes, you can, no problem. Take care to pack it airtight though. When you want to use or eat it take care to defrost it will in time. The caramel may become hard, though it depends on the recipe, so be patient before eating. Read more here on freezing caramel and its freezing point.