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The true hallmark of a perfect brownie is one that has that enviable shiny, glossy, crinkly, tissue thin crust on top. Not every recipe yields that gorgeous crust. And not every baker can produce that crust reliably.
At least, not until they read this article! I’m diving into the science behind that shiny thin crust we all love and want for our brownies.
I have a LOT of brownie recipes in the archives of this website. Deciding which one to bake can be a challenge. The good news is that you can apply the methods I detail below to pretty much any recipe. Some of my published recipes already use these methods, and others can be benefitted from them to all but guarantee that brownie crust.
The Key To Glossy Brownie Crust? Dissolve Your Sugar Properly!
Dissolving sugar into the brownie batter is the key to developing that shiny crust.
This is a challenge for a couple reasons, and is why that shiny, glossy, tissue thin crust can feel so elusive.
If you notice your brownie batter has lots of graininess to it from the sugar, it likely won’t develop a very pronounced brownie crust.
So what do we do?
There are a few methods to improve how much the sugar dissolves into the batter.
All the methods described below were tested on my most popular brownie recipe: Best Chewy Brownies. That’s the recipe you see photographed in all the comparison shots in this article.
How to Make Brownies with Shiny Thin Crust
Method 1: Add Sugar to Hot Butter
There’s an important caveat to understand regarding this method: sugar only dissolves in water. Not fat. In fact, you can dissolve a lot of sugar in water — twice the amount by weight of sugar in any amount of water as discussed by Dr. Pia Sorensen in Adam Ragusa’s video on investigating how brownie skin forms. If you’ve ever made simple syrup you know how sugar can dissolve completely into water. That same effect won’t happen if you heat oil and add sugar.
About twenty percent of butter is made of water. If that water content is hot from melting the butter when you add in the sugar, it will dissolve more readily into the water. This helps to create that shiny crust, not just on brownies but also chocolate cookies and even chocolate chip cookies using melted butter. I always add the sugar into the hot butter. Look what happens when you don’t:
It has the added benefit of cooling the butter more quickly so you can add your eggs sooner without scrambling them.
Method 2: Whipping Eggs + Sugar
I first experimented with this technique of whisking the sugar into the eggs back in 2012. It helps to agitate the sugar to better dissolve into the water content of the egg whites and for the sugar and egg proteins to form bonds.
I originally learned about it from ScientificallySweet.com, but this meringue technique can actually be traced back as far as 1929, as Stella Parks describes in her recipe book, BraveTart: Iconic American Desserts, when discussing how Swans Down changed the brownie game by publishing a brownie recipe in a mail order cookbooklet where the “directions called for whipping the eggs with sugar and for melting the butter and chocolate into a sort of ganache. This made brownies more fudgy than cakey…”
The goal is to aerate the eggs and sugar so much that they create a foam. The intensity and structure of this foam yields different results:
In my Ultimate Fudgy Brownie recipe, I call for whipping the eggs and sugar for 3 minutes. This creates kind of a meringue crackled crust on top.
In my Brown Butter Brownies (pictured above), heavily inspired by Stella Parks, I call for beating the eggs and sugar until they’re completely and totally foamed, which takes around 8 minutes. The time actually totally depends on your mixer power.
In my Best Easy Brownie recipe, I shortcut this foaming technique by calling for whisking the eggs, sugar, and butter together by hand for 1 minute. However, this is done after the sugar is added to the hot butter and melted chocolate mixture. The heat encourages dissolution of the sugar into the water content.
Method 3: Use powdered sugar instead
Powdered sugar is finely ground and will dissolve into the batter’s water content much more quickly and easily.
Swap in powdered sugar for granulated sugar using the following conversion:
1 cup granulated sugar = 1 ½ cups plus 2 tablespoons powdered sugar
Or, better yet, use a kitchen scale and just measure the same weight of total sugar.
Important sugar consideration: Your recipe must have ENOUGH sugar to develop a tissue thin crust. The sugar creates viscosity which is required to develop that crust. Well balanced brownie recipes have enough sugar to be fudgy and moist with the crust on top without becoming cloyingly sweet.
How MOISTURE Affects Brownies in Crazy Ways!
When it comes to dissolving sugar into brownie batter, it’s helpful to note there’s a small amount of water content in egg whites. There’s no real water content in melted chocolate. So basically, there’s not a lot of places the sugar can dissolve in a low moisture recipe like brownies! This is good, because as you’ll read below, too much water kills that shiny crust.
I know this seems counterintuitive since we need some water content for the sugar to dissolve into, but too much will create a looser consistency (instead of that thicker viscosity we need). This prevents the surface of the brownies from drying out enough to form that ‘skin.’
That’s why you’ll see me use whole eggs + egg yolks in my recipes. Too many egg whites adds too much water which creates brownies that have lots of holes on top instead of a nice crust.
This is also why my Browned Butter Brownie recipe has such a brilliant crust – the butter’s twenty percent water content has been evaporated in the browning process. Same goes with my Chewy Brownie recipe, which uses part butter, part oil. Oil contains no water.
The moisture conundrum is also why using brown sugar in a brownie recipe can negatively impact that glossy skin.
If you live in a very humid climate, it can be extremely difficult to achieve the brownie crust. Just like it’s difficult to create meringue-based desserts in humid climates, the moisture prevents the top of the brownie batter from drying out enough to create that skin.
Method 4: Use chocolate chips
Most brownie recipes that yield that crinkly crust involve solid chocolate in one form or another. Either you’re melting chocolate into your batter and/or adding chocolate chips.
One thought is that the melted chocolate contains more fat and less moisture than butter. So if a large portion of the fat in the recipe comes from chocolate, there will be less water to prevent that crust from forming.
My Best Chewy Brownie recipe contradicts this as it’s made with only cocoa powder and almost always yields a shiny crust. So I decided to do some testing.
What I discovered was that the chocolate chips can make a significant contribution to the development of that brownie skin. When I’ve made the same brownie recipes with and without chocolate chips, the chips enhance the shiny crust on brownies:
I’m not 100% sure why, but I have two thoughts on this. One is that the soy lecithin and milk solids in chocolate chips aid in the development of that crust. It could also be that chocolate chips include dissolved sugar already, and that’s what helps the crust to develop.
How to Add Chocolate Chips to Brownies:
For an 8 by 8-inch pan of brownies, add around ¾ cup (128 grams) chocolate chips. For a 9 by 13-inch pan of brownies, add 1 ½ cups (256 grams) of chocolate chips. Gently fold the chips in to the brownie batter as the final ingredient.
Bonus Tip: Chill Your Brownie Batter Overnight!
Allowing the brownie batter to sit for an extended period gives the sugar time to dissolve into the water content of the batter. This also thickens the batter.
Alice Medrich, author of Seriously Bitter Sweet: The Ultimate Dessert Maker’s Guide to Chocolate, writes that “refrigerating the brownie batter in the pan for several hours, or as long as two days before baking, wreaks enormous transformations: it improves the top gloss and crustiness, and it also blends the flavors so that the brownies taste much richer — and the texture is chewier too.”
Here are some final side-by-side looks at the SHOCKING differences between all these brownie made from the SAME recipe!!
Photos by Ashley McLaughlin.
Hi, loved the recipe except that it was a little too bitter for my liking. Can I reduce the amount of cocoa powder to 1/2 cup without affecting the outcome?
Hi Cristina! Altering the cocoa powder will change the texture of the brownies, so I wouldn’t recommend that. Feel free to adjust the sugar content, which will, of course, help the brownies be sweeter – but it will also change the texture of the brownies (learn more about sugar’s role in baking here). I would recommend instead adding a sweeter chocolate chip inside the brownies (milk chocolate is great for that), to make the overall flavor of the brownies sweeter without messing with the chemistry of the recipe. You could also add a buttercream on top! I hope something here helps! Happy baking 🙂
Thank you very much,l hope to follow your recipe make the brownie the best,because before l only used the box mix.Thank you Sr. Mary John in Michigan
Will the brownie batter dry out in the fridge? I do that for my chocolate chip cookies but they always end up drying out in the fridge.
Hi Kassie! As long as you cover the brownie batter well with plastic wrap, it definitely shouldn’t dry out in the fridge. Same goes for your cookie dough – be sure to keep it well wrapped in plastic wrap, and then place it inside a freezer bag or an airtight container, if your fridge is extra dry. Happy baking! 🙂
Thank you for sharing this! I adore brownies! They’re my favorite dessert. I am low-key hoping for an ultimate brownie handbook to go with my copy of your cookie handbook.
Can u guide little about eggless brownies ,I generally use thick curd n mux powdered sugar with curd then add melted butter n chocolate then dry ingredients
Hi Ujval! Unfortunately, we don’t have any experience using egg substitutes in baking, but you’re welcome to experiment and see if you can find a replacement that works for you!
This is so so informative! Thank You so much for sharing your expert information! I crave brownies sometimes when I least expect it then after reading this article I know why! I love a perfect brownie and I don’t always get a perfect brownie. But I will definitely try thieve new procedures! Hopefully I will accomplish a true gourmet brownie! But I actually was hoping to put a peanut butter topping on one layer then a thin ganache on top of the peanut butter layer so can that be done with your recipe?
Thank you for your knowledge and for sharing!
Hi Rosita! So glad Tessa’s information was so helpful! We haven’t tried the layered brownies you’re describing, but you could absolutely experiment and see how it goes! Alternatively, I recommend giving these Peanut Butter Stuffed Brownies a try, and you could always add a layer of ganache on top of the cooled brownies if you like! Happy baking 🙂
I’m a brownie mix fan, not just because it’s easier but usually cheaper than from scratch. I just wanted to add my recent experience. I was in a hurry to get to brownies and put the pan in the oven before it had reached temperature. My brownies came out looking like cake. No crust whatsoever. Even had air bubbles on the surface. Still tasted fine, but visually disappointing. I have to say ALL of your brownies have a lovely crust, just some are a little better. I will definitely take a few ideas from this to make my brownie mix work better, like adding chips and letting the batter rest. Thank you
Hi Kathy! Correct oven temperature is definitely important when it comes to baking. It’s tough to say for sure what went wrong with your brownies as you weren’t using a recipe of ours, but hopefully our tips help with your future bakes! Happy baking 🙂
I usually skip over what I call the yada yada when I’m looking for a recipe. But I’m also a science wonk, in fact, my husband has bought me two food science books over the last few years knowing that it will entice me to start baking something he likes LOL. You made an excellent case based on scientific experimentation with a hypothesis and then show the results. This science/baker nerd is very impressed! It is so interesting that just last night I searched for an ‘easy’ brownie recipe that of course, I improved based on my sci/baking experience and intuition. I changed out 1/2 the oil to butter (what effect would the approx dif in water % in unsalted make), melted dark, not semisweet, chips in the fats, and sugar. It came out really well for a 1 bowl recipe but alas little to no shiny crust. So I googled and found your blog. I will now be sure to have sugar dissolve completely, as to placing the batter in the fridge for a few hours or overnight? I am not strong enough for that (maybe make a double batch?) Just like there is no way that this household could wait like an hour before cutting and eating. I just stick it in the outside fridge (AKA front porch metal shelving) and deal with some sticky crumbs. Today it is even better.
Welcome to Handle the Heat, Elizabeth! So happy to have you following along 🙂 Check out our other Baking Science articles HERE, so happy that you loved this article! We have quite a few (40+!) brownie recipes on our site, but I’d like to share a couple of our most popular recipes, which use some of the tips from this article: Chewy Brownies and Ultimate Fudgy Brownies. Be sure to read through the pink tip box above each recipe as Tessa details the importance of each ingredient and the process to achieve that shiny thin crust. I hope that helps!
I am a brownie fanatic. This is the best explanation of brownie science I have seen in several decades of baking.
Thank you.
That’s so great to hear! I’ll be sure to pass this along to Tessa, it’ll make her day! Thanks so much for taking the time to comment 🙂
Hey Tessa,
I’m a newbie for your baking recipes. I did try your brown butter brownie it came out perfect in my 1st two trials but after onwards it came out with a crust top with no shiny crinkle top? Am I doing anything wrong? I followed your recipe again again for more 10 times now. But I’m not getting the same shiny top anymore. Please help me out there!
And for your powdered sugar recipe. How does it work should we add powder sugar instead of granulated sugar and beat with eggs? Do we get the same consistency with tissue thin shiny crust.
Hi Zeenath! I’m sorry to hear you’re having issues! Did you change anything between the first two batches and the rest? Any ingredients, brands of ingredients, pan…etc.? Did your kitchen environment or your mixer change at all? It’s hard to say for sure what happened without having baked along with you as your first two batches turned out perfectly!
For the powdered sugar, yes, as discussed in this article, you would swap in powdered sugar for granulated sugar and follow the recipe as written. We include a conversion in the article as well as detail the difference between the two and include pictures of each batch 🙂 I hope that helps! Please let me know how your next batch goes!