Cakey vs. Gooey Brownies – The Science Behind A Brownie’s Texture

Deceptively simple to make, yet, so many ways to make them: brownies.

There must be thousands of recipes for making brownies. And most of them will probably make a delicious brownie. But, you might be looking for one that’s a little more gooey. Or do you prefer yours slightly more cakey? Sure, you can test countless recipes, until you find your perfect one. But, by using a little bit of science, you can also tweak almost any brownie recipe to make it just the way you like it!

Gooey vs. Cakey Brownies

There are countless ways to tweak brownies, but, one of the most common basic distinctions is that between a gooey or cakey brownie. Should it be moist, slightly sticky, dense and soft? That is, should it be gooey, or fudgy? Or, should it be fluffy, a little dry, and crumble apart more easily, that is: cakey?

It’s a sliding scale, and you can make just about any brownie texture from very gooey, to very cakey. Some might call brownies that fall in the middle chewy, however, we’ll just call them slightly gooey, or slightly cakey. And, since we all have different personal preferences there’s not one ‘perfect’ brownie recipe out there. It’s up to you to make your own ‘perfect’.

In creating that ideal brownie, there are two main levers you can pull and we’ll have a look at both:

• The ingredients: which and in which quantities
• The process: how you make the batter, and, most importantly, bake them

Looking for a brownie with a crispy top specifically? Then read our guide on crispy top brownies.

Tweaking ingredients to change the consistency

To evaluate the impact of ingredients on the consistency of brownies, we will use one basic recipe. There are countless more variations (black bean brownies anyone?), but, the science behind the types of ingredients will be similar for all. Our simple brownie recipe uses the following ingredients:

• Chocolate: milk, dark or extra dark
• Cocoa powder
• Butter: or (plant-based) margarine
• White wheat flour: e.g. all purpose flour
• Sugar: white or brown, not a syrup
• Eggs
• Baking powder

By increasing, or decreasing the quantities of each ingredient, you can tweak the final consistency. Of course, tweaking quantities also impacts flavor, but, for now, we’ll focus on the gooey- vs cakeyness.

Butter & Chocolate (the fats) increase gooeyness

Generally speaking, the best way to increase the gooeyness of your brownie is to increase the fatty ingredients. Fats are a group of molecules that make food taste creamy and rich. As such, they contribute to the gooeyness of a brownie. In our brownies, the main fatty ingredients are chocolate and butter. Butter contains over 80% of fat whereas most chocolates will contain up from 30-35% fat. As such, increasing the amount of chocolate and butter in your recipe will increase the gooeyness of your brownie.

But, there is such a thing as too much gooeyness! At high temperatures most fats melt, at lower temperatures, they set. Molten fats especially can form, or hold onto sturdy structures. Molten fat simply forms a puddle. So, if a brownie contains too much fat it will simply collapse. It’s a matter of balance.

Can you use oil instead butter?

Instead of butter (or margarine), brownie recipes may call for oil. Chemically speaking, oils and the fats in butter are very similar. The main distinction is the point at which they turn solid. Butter fats are semi-solid at room temperature, whereas oils are liquid at room temperature. When a brownie that was made with butter cools down after baking part of the fat will turn solid again. However, the oil will remain liquid. As such, brownies made with oils tend to be a little softer than those made with equal amounts of butter. And, they’re also a bit more prone to oil leaking out. Butter on the other hand contributes more to the overall flavor of a brownie.

Researchers have been doing a lot of work on trying to find fat replacers since they do contain a lot of calories. However, this hasn’t been easy. One unexpected successful replacement for fats seems to be beans! They can help create that creamy, rich structure.

Cocoa powder helps make a more cakey brownie

Chocolate is made of mostly cocoa butter, sugar, cocoa powder, and possibly some milk. Most of the chocolatey flavor comes from just one ingredient: the cocoa powder. Most of the fat on the other hand comes from the cocoa butter. As such, if you want to reduce the amount of fat, but keep the strong chocolate flavor, you’ll need to use unsweetened cocoa powder. Most cocoa powders contain anywhere from 10-20% fat, a lot less than chocolate! It’s why using cocoa powder will make a more cakey brownie.

Cocoa powder also helps to thicken and firm up a brownie because it is so dry. It will hold on to some moisture (though not as much as flour does) and bind the brownie as a whole. That also results in a less fudgy brownie.

Flour increases cakeyness

You can’t make brownies with just fats. You’d end up with a puddle. You need other ingredients to bring it together. One of those is flour. You can make brownies without flour (or other starch), but they’ll be on the gooey side of the spectrum. Flour helps to create that cakey texture. Wheat flour is made up of mostly starch. The starch absorbs water, swells and sets in the oven through a process called gelatinization. This process creates the structure of bread, thickens sauces, and enables cakey brownies.

Again, too much is not good either. A brownie that contains too much flour will slowly turn into a chocolate cake instead of a brownie. It will lose some of that richness and depend more and more on the flour for overall texture, instead of the fats and other ingredients.

Using (corn) starch instead of flour

Some brownie recipes may (also) call for using a pure starch such as corn or potato starch. They play a similar role to wheat flour and also make a brownie more cakey. The resulting textures might be slightly different, but won’t vary hugely from that of flour.

Sugar contributes crispiness

Next up is sugar. The role of sugar in cakey and gooey brownies is a little more nuanced than that of flour and fat. Sugar does impact the overall texture, but it’s effect is less pronounced. First of, the amount of sugar is often greatly determined by the desired flavor profile. Sugar makes the brownie sweeter.

Secondly, sugar can play a major role in creating a crispy outside layer of the brownie. Without sugar, brownies will have a harder time crisping up. But, sugar also plays a role in the inner texture of a brownie. Sugar holds on to water. By holding onto the water, it doesn’t become available for the flour, limiting the gelatinization process. As such, sugar increase gooeyness.

Eggs enable gooeyness

Brownies are made with a lot of fat and little flour. It’s what sets them apart from most other cakes. A risk of using such a large amount of fat is that is may seep out and split. This is where eggs come in. Eggs contain lecithin. This is an emulsifier meaning it ensures fat and water remain mixed. As such, it reduces the chances of the fat escaping from the brownies. By adding eggs, you can add more fat, enabling a more gooey brownie.

Egg proteins stabilize

The emulsifying property is a common reason for using eggs, but not the only one. So far, we’ve barely added any water to the brownie, apart from some of the butter. Eggs though are mostly water. This moisture is crucial for the flour to do its job and gelatinize. But if it were just for the moisture we might have also added water or another liquid. Instead eggs also serve another crucial role: helping the brownie set. Eggs contain a lot of proteins. It’s what makes an egg set when you boil or bake it. These same proteins also help a brownie to set by forming a sturdy network that holds the ingredients, including the fats, together.

You may notice that most flourless gooey brownie recipes do contain eggs. The eggs take over the stabilizing role of the flour. Vegan flourless brownies will often contain some sort of an egg replacer to help take over this role as well.

Again, too much does more harm than good. Brownies can taste very eggy if they contain too many eggs and aren’t baked for long enough. Also, overbaking the brownie can cause the proteins to push out water instead of hold on to it, resulting in a drier brownie.

Baking powder is quite useless in gooey brownies

By now, we know that gooey brownies contain more fat than cakey brownies and have less of a solid structure. It is why they are denser as well. In order for a brownie to be light and airy it needs to be able to hold onto air bubbles. However, if the structure is not strong enough to hold onto these air bubbles, there’s not much use creating them. It will simply collapse back onto itself once it’s come out of the oven.

It is why baking powder is quite useless in (very) gooey brownies. Baking powder creates pockets of gas within a brownie (or cake for that matter). However, in order for those pockets of gas to remain standing, the surrounding structure needs to be quite sturdy. In a (very) gooey brownie that’s often not the case. The sides may hold up, but the center may well collapse again.

Ingredients that do NOT influence consistency

So how do you know whether you can freely add or change an ingredient without it impacting the brownie’s consistency? It’s a matter of experience. But, there are a few types of ingredients you can play around with without any cakey/gooey consequences.

Salt

Brownie recipes may contain a little bit of salt. However, the salt is just there for flavor. It can strengthen the flavor of a brownie, or bring out some of the more complex flavor profiles. But, it will not impact the consistency of your brownie.

Flavors

The most frequently used flavoring in brownie is probably vanilla extract. But, you can add other flavors, such as almond extract or instant coffee powder. If you’re using concentrated flavors such as these, they won’t impact a brownie’s consistency. The amount you’re using is too low.

Toppings

Most toppings will not impact the consistency of your brownie. However, that is not true for all. Toppings that simply sit in or on top of the batter, without interacting with it are your best bet. Nuts and dried fruits work well most of the time, without impacting the brownie’s consistency. However, fresh or frozen fruits can impact the consistency of the brownie, since they might impact (a lot of) moisture. The same goes for chocolate chips which may release a lot of fat that can interact with the brownie. If used in moderation, the impact will be limited, but a lot of them will impact the overall eating experience.

Impact of process on consistency

Even though tweaking the recipe will have a tremendous impact on the final brownie outcome, it’s not the only thing you can do. Many gooey recipes can still turn out cakey and vice versa, depending on how they’ve been made.

Longer baking makes a brownie more cakey

First and foremost, the baking time (and temperature) impact gooeyness. Keep in mind that in order for a brownie to be gooey it’s structure shouldn’t be too strong (not too much flour) and it should contain enough water and especially fat to maintain a moist consistency. The longer you bake a brownie the more moisture evaporates and the sturdier the structure becomes. In other words, it becomes more cakey. Many gooey recipes will still become cakey if left in the oven for (way) too long. It is why many recipes call for pulling a brownie out of the oven before a tester comes out clean.

Pan sizes matter

The size of your pan as well as the amount of brownie you’re making both impact the final consistency. The thinner the layer of batter, the shorter it needs to bake, so the more likely it is to set more fully. Also keep in mind that gooey fudgy brownies aren’t as good at holding onto their own weight, so it’s best to make those a little thinner.

Storage in the fridge increases cakeyness

Keep in mind that fats make a brownie creamy and gooey. A brownie is softer and more gooey if the fats are (at least partially) liquid. It is why a brownie stored in the fridge will be denser than one that’s been heated up just slightly before serving. It may seem like the cold brownie is more cakey, simply because it is firmer, but it’s actually the temperature that is to blame here.

Because of its high fat content, brownies can be stored for quite some time without them turning stale. However, over time they will turn stale and storing them in the fridge does accelerate this process.

References

The Science Behind the Perfect Brownie – Kitchen Conundrums with Thomas Joseph, March 7, 2015, video on YouTube, link