taking a scoop out of a creme brulee

The Science of Creme Brulée (+ Recipe)

It’s the contrast between its soft and silky inside and crackly brown top which makes a creme brulee such a great dessert. Yet it’s simple to make. No long list of ingredients, nor complex processes are required. Instead, making a creme brulee is all about getting the most out of two simple, but extremely powerful ingredients: eggs and sugar. Use eggs to thicken, sugar to caramelize.

What is creme brulee?

Creme brulee, or crème brûlée as it’s originally called in France, is what its name says it is: burnt cream.

The bottom of a creme brulee is made up of a rich and creamy mass of cream which has been set by egg yolks. This is covered in a thin, crackly layer of caramelized sugar. So no, the cream isn’t actually burned, but, the thin top layer (almost) is!

finished creme brulee
Creme brulee

Creme brulee requires just 3 ingredients

A creme brulee is a great example of a dessert that gets the most out of just a few ingredients. To make one, you only need 3 ingredients:

  • Cream: provides richness & creaminess
  • Egg yolks: thicken the cream
  • Sugar: for sweetness and the crunchy brown layer on top

You can add a few other ingredients, but they aren’t crucial. Most just add flavor.

Each of these three ingredients plays a crucial role in making creme brulee. Let’s have a quick look at each of them.

Cream – for creaminess

Cream, or heavy cream, or whipping cream, contains over 30% fat, milk fat to be precise. Milk fat is solid at room temperature, but it melts at temperatures just below body temperature. As such, it can melt in your mouth. The fat makes the creme brulee creamy and rich in texture.

lemon custard pies
These lemon custard tarts also use egg yolks to firm up.

Egg yolks – for thickening

We’re just using the yolks from the egg here, no egg whites. The yolks of an egg contain a considerable amount of fats, about 35%. These add creaminess to the creme brulee, just like the fat in the cream. But, egg yolks contain two other crucial ingredients.

First of all, egg yolks contain lecithin. Lecithin helps water and fat to mix. It’s an emulsifier. It’s not crucial for a creme brulee to work, but it sure helps.

The other, most crucial components of egg yolks, are the proteins. About 15% of egg yolks is made of these proteins. Proteins in egg yolks are sensitive to heat. When heated, they denature. In other words, they unravel. Unraveled egg yolk proteins are great at holding onto moisture and thickening liquids. If you’ve even cooked or baked an egg, you’ve seen the proteins at work. A cooked egg has turned solid. It’s the proteins that make it turn solid.

Egg yolks are true power tools. You can use them to make a range of custards and creamy desserts.

What about the egg whites?

You can make creme brulee without any egg whites. However, you could add some, they wouldn’t immediately fail. But, a creme brulee with egg whites will be less creamy. Egg white doesn’t contain fat, so doesn’t add that creaminess.

Also, adding egg white does increase the chance for the creme brulee to become ‘eggy’, especially if you don’t fully whisk in the egg whites. You can end up with local pieces of cooked egg white.

Don’t throw away the egg whites though! Use them to make a meringue, or maybe some royal icing? Or, use them in just about any pancake recipe.

creme brulee with few scoops taken out
Creamy creme brulee

Sugar – for crunch

So far, a custard, made with just cream and eggs isn’t particularly special. It’s the addition of the top crackly layer that sets a creme brulee apart from the ‘competition’! It provides for some textural contrast: creamy inside + crackly top.

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Sugar can some very unique properties and one of them is that it can caramelize when you heat it to very high temperatures. During caramelization, the sucrose molecules in sugar react into new brown and flavor molecules. Caramelized sugar isn’t as sweet anymore. Instead, it may even taste a little bitter.

Which type of sugar?

For sugar to caramelize properly into a hard disk you should use ‘regular’ sugar. That is, sugar that is made from sugarcane or beet. This sugar is made up of the molecule sucrose and caramelizes well.

Don’t use sugars with added molasses, or sugar syrups. These tend to make a sticky brown layer on top, instead of a nice crackly one.

You can use white sugar, but you can also use slightly unrefined cane sugar. This sugar is light brown in color, but isn’t sticky. Don’t use powdered sugar, it’s tricky to caramelize, even though it’s also made from the same chemical molecule. The very fine powder is more prone to burning and dissolving.

What about the custard layer?

Note, the type of sugar you use for the caramel layer on top is more important than the one you use in the custard below. In the custard, you can use powdered sugar. Keep in mind that using brown sugar will change the color of the custard!

granulated white beet sugar crystals
Regular sugar, made from sugar beets, works great to go on top of a creme brulee.
Sugar in the custard

Most creme brulee recipes will also contain some sugar in the cream + egg yolk custard at the bottom. The sugar adds a little bit of sweetness, but also supports the egg yolks in creating that creamy texture.

How to make creme brulee

Making creme brulee consists of three steps:

  1. Dissolve sugar in cream – to make it smooth and without any grittiness
  2. Thicken the cream – by denaturing the egg yolks
  3. Caramelize the sugar – to make a crispy layer

None are particularly complicated. However, they do rely on a delicate balance between time and temperature. Heat the egg yolks too much, and you’ll end up with scrambled eggs. Heat the sugar for too long, and your creme brulee is (too) burnt.

Step 1 – Dissolve sugar

Creme brulee should be very smooth. You don’t want any grittiness or clumps in the bottom layer. As such, you want to make sure that the sugar in the bottom layer has dissolved completely.

Sugar dissolves well in water, and cream contains a lot of water. It dissolves even better – and faster – in warm water. It’s one reason why most recipes start by (slightly) heating the cream with sugar.

There’s another reason you may heat the cream: to add flavor. There are different ways to add flavor. You can directly add the flavor, e.g. a vanilla extract, into the cream. This is the quick and easy way. However, you can also decide to infuse flavor. Add the flavorants, e.g. spices or coffee beans, to the cream and let them steep. Flavor molecules are extracted during this time and will sit in the cream. This goes a lot faster if you heat the cream. Hence, the heating step.

coffee soaking in creme brulee cream sugar mixture
Infusing coffee flavor into cream. This goes faster if the cream is warm.

Step 2 – Cook yolks

The power of egg yolks is what will set the cream + sugar + yolk mixture. Undercook the creme brulee and it will still be liquid. Overcook it, and it might curdle.

It’s why during this step you carefully cook the egg yolks. In a creme brulee you want the entire filling to be set, smooth and firm. You achieve this by not whisking the mix during heating. By whisking you can disturb the formation of some of those protein networks.

Use an oven

So, creme brulees are generally cooked in the oven. More specifically, they are cooked within a water bath in the oven. The water bath ensures that the cream doesn’t become too hot. It serves as an insulator. If you’d cook the creme brulee without the protection of the water bath the outside could be overcooked before the inside is cooked.

You can cook a creme brulee without the water bath. But, the temperature of the oven should be turn down a lot lower.

Or, use a pressure cooker!

Instead of placing the trays in hot water in the oven, you could also use a pressure cooker for similar results, just as you would for a cheesecake.

Step 3 – Caramelize sugar

Before you proceed to step 3, you need a little patience. For best results, it’s best to cool the center down completely first. In this step you’ll be applying a lot of additional heat to the top of the creme brulee, to caramelize the sugar. If the center is still hot, it is very easy to overheat it and still curdle that egg. However, if it’s cold it will merely warm-up, not overcook.

Once the set cream has cooled down completely it’s time to sprinkle some sugar on top (see also video above). Aim for a thin layer of sugar. Too thick, and it will be hard to caramelize all. Too thin and you can’t get one complete disk of caramelized sugar on top.

Next, use a very strong source of heat. A blowtorch works best, but you could also use the grill function of an oven. Slowly, but steadily, heat the complete top layer of sugar until all of the sugar has turned brown, it has caramelized!

The caramelized sugar will cool down quickly and form a hard, snappy disk on top of the creme brulee. Ready to be eaten!

Do it last minute

A good creme brulee has a soft creamy center and a crackly brown top. To ensure the best results, it’s best to caramelize the sugar right at the last minute. Over time, the sugar layer can re-absorb moisture and become soggy again. When the disk on top loses its crackliness, the creme brulee will lose its charm…

taking a scoop out of a creme brulee

Creme brulee

Prep Time: 15 minutes
Cook Time: 30 minutes
Additional Time: 2 hours
Total Time: 2 hours 45 minutes

The recipe is based on a recipe from America's Test Kitchen (The Complete America's Test Kitchen Cookbook 2001-2016). We made a few tweaks.

You need ramekins or other small oven-proof dishes, as well as a large heat-proof tray that will fit all four comfortably.

Keep in mind that the creme center needs to cool before you caramelize the sugar! This will take a couple of hours.

Ingredients

  • 290g whipping cream (high fat content)
  • 30g sugar
  • 4 egg yolks**

Top layer

  • 4 tsp of granulated sugar

Optional (for flavor)

  • 25g roasted coffee beans OR
  • spices to taste OR
  • 1 tsp instant coffee OR
  • 1/2 tsp vanilla extract

Instructions

  1. Add the cream and sugar for the center to a pot. Gently heat to dissolve all the sugar.

Flavoring, steeping

  1. If making a flavored creme brulee using whole spices or coffee beans:
  2. Add the whole spices to the cream directly.
  3. If using coffee beans, crush them into smaller pieces, e.g. using a mortar and pestle. Add to the cream.
  4. Gently bring the cream, flavorants and sugar to a boil. Turn off the heat and leave to steep for at least 30 minutes. Longer steeping will increase the strength of the flavor*.
  5. Pour the cream through a sieve to remove the spices/beans.

Cooking the creme brulee

  1. Pre-heat the oven at 160°C (325°F).
  2. Whisk the egg yolks into the cream + sugar mixture. Ensure the eggs are whisked in well. Note, the cream should be at room temperature! If the cream is too hot, it will cook and scramble the eggs.
  3. Pour the mixture into 4 separate ramekins/oven dishes. Ensure they are all filled equally to ensure even cooking.
  4. Take a large oven dish that comfortably fits your four ramekins. Place the ramekins in the tray.
  5. Pour in hot, boiling water to surround the ramekins. !! Ensure your oven dish can handle these types of sudden temperature changes!
  6. Place in the oven and bake for approx. 25 minutes. The creme should be slightly firm to the touch and wobbly. Keep in mind, if you're making a thicker layer, it will need longer to cook and vice versa.

Caramelizing sugar

  1. Take the ramekins out of the oven and leave them to cool down, preferably in the fridge once they've lost most of their heat.
  2. Sprinkle approx. 1 tsp of sugar over each ramekin. It should cover the surface, without being a thick layer.
  3. Turn on the grill of your oven or use a blowtorch to caramelize the sugar on top. You want to sugar to turn brown, not black.
  4. Serve and enjoy!

Notes

*If steeping for longer periods of time, do so in the fridge to prevent spoilage of the cream.

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2 Comments

    • Hi Tina!

      Curious to know a bit more about your creme brulee to help you answer the question. Was the texture fine? If the texture isn’t as smooth as it is supposed to be you might have added the hot liquid too quickly to your egg (yolks). That may cause the eggs to scramble and you’ll end up with more pronounced areas of egg taste.
      Creme brulee will always taste a little like eggs, since you’re using eggs, but if it’s too much to your taste and if the texture is quite firm, you could consider slightly reducing the amount of egg (though that will definitely impact the texture as well, so don’t remove too much at once).

      Hope that helps!

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