If you love rich chocolate desserts, these Guinness brownies are about to become your new favorite. They’re deeply fudgy, intensely chocolatey, and topped with a creamy Guinness-infused frosting. I promise you don’t have to like beer to love these St. Patrick’s Day-perfect brownies!
I originally published this recipe in 2018, and I’ve since updated it with new photos and extra success tips for consistently excellent results.
Before you worry—these brownies do not taste like beer. Instead, Guinness stout enhances the chocolate flavor with roasted, coffee-like notes and a hint of caramel sweetness. It’s the same reason stout is often paired with chocolate desserts, such as this Guinness chocolate cake. The flavors naturally complement each other.
These Guinness brownies are decadent and deeply chocolatey, but not overly sweet. A chocolate dessert for a grownup palate!
- Texture: dense, moist, and fudgy
- Flavor: dark chocolate with roasted malt notes
- Frosting: creamy, with hints of espresso and caramel
Why You’ll Love These Guinness Brownies
These brownies stand out from typical chocolate brownies because of their deep, complex flavor and ultra-fudgy texture.
Here’s what makes them special:
- Complex chocolate flavor: Guinness stout intensifies the pure melted chocolate with its roasted, coffee-like notes.
- Ultra-fudgy texture: Close in texture to my seriously fudgy homemade brownies.
- Creamy Guinness frosting: Light, smooth, and slightly espresso-forward with subtle malty caramel notes.
- A wonderful dessert recipe for St. Patrick’s Day… or anytime you’re craving a rich chocolate dessert!
What Does Guinness Add to Brownies?
Dark, smooth, and creamy, Guinness stout contains roasted barley, which contributes flavors similar to roast coffee, cocoa, and caramel. Guinness is often used in baking and almost always paired with chocolate. The two work well together because Guinness, like coffee, intensifies chocolate’s natural flavor.
- Have you ever had this chocolate cake with hot coffee in the batter before? It’s just like that.
Truly, you don’t have to like beer to love desserts made with Guinness! Desserts like my Guinness cupcakes don’t taste like beer. Rather, they have a more complex chocolate flavor with a malty background.
Reducing the beer first intensifies these flavors while preventing excess liquid in the batter. We take that same first step in this recipe for Guinness chocolate cake. More on this below!
Other Ingredients You Need
Besides a bottle of Guinness, the rest of the ingredients are all pretty typical brownie staples:
- Butter: You can make brownies with butter, oil, or both; but in testing, we liked these brownies best with all butter.
- Chocolate: Use 8 ounces (2 standard baking bars) of semi-sweet or bittersweet chocolate. Since this is the only chocolate in these Guinness brownies, use a good-quality brand—I typically use Ghirardelli brand.
- Sugar: Sugar does more than sweeten brownies. As the batter bakes, it liquifies to create a softer center and rises to the top, forming that shiny, crackly surface.
- Eggs: Eggs bind, add richness, tenderize, and provide structure. This recipe uses 3 eggs for a tight crumb and melt-in-your-mouth texture.
- Flour: More flour makes cakier brownies. For dense, fudgy brownies, you only need 1 cup.
- Salt & Vanilla: To balance all the flavors.
- Espresso Powder: Optional, but I recommend it for a deeper chocolate flavor. It’s added to both the brownie batter and frosting. You can find espresso powder in the baking or coffee aisle at the grocery store or online.
- Confectioners’ Sugar: For sweetening the frosting.
Why is there no baking powder or baking soda in these brownies? Adding baking powder or baking soda lifts brownies up and creates a cakier result. But today, we want a brownie so dense and fudgy that it’s basically 1 step up from eating pure chocolate—just like these seriously fudgy homemade brownies.
The Key Step: Reduce the Guinness
The secret to bold Guinness flavor in your brownies without ruining their texture is reducing the beer first. Simmering the beer concentrates its flavor while preventing excess liquid in the batter, so the brownies stay dense, moist, and perfectly fudgy instead of cakey.
By reducing a full bottle of Guinness on the stovetop, the water evaporates while the flavor intensifies. The result: malty stout flavor without compromising the brownie texture.
Here’s the process:
- Pour one bottle (or can) of Guinness stout into a saucepan.
- Let it simmer until it reduces to about 2/3 cup (takes about 20 minutes, totally hands off). This is less than half the liquid we started with, but triple the flavor.
- Let it cool slightly. Or reduce the Guinness in advance, and refrigerate until you’re ready to make the brownies.
This technique is similar to reducing fruit or champagne for baking—less liquid, more flavor. We do the same thing to concentrate strawberry flavor for strawberry cake, apple cider flavor for apple cider donuts, and champagne for champagne cake roll.
We’ll use 1/2 cup (120g/ml) of reduced Guinness in the brownie batter, and the remaining 2 and 1/2 Tablespoons (40g/ml) in the frosting.
How to Make the Best Guinness Brownies
Once you’ve reduced the Guinness, the batter comes together quickly.
Melt the butter and chocolate together to create a smooth base for these dense, fudgy brownies. It helps to cut the butter into pieces so it melts evenly. You can use the microwave or stovetop. Whisk in the sugar and the reduced Guinness, then the eggs and vanilla, and finally the dry ingredients. The batter will be thick and shiny.
Spread it into a lined 9-inch square metal baking pan (not glass or ceramic) so the brownies bake evenly.
Guinness Frosting
The brownies are fantastic on their own, but their decadent nature begs for something creamy. While you could enjoy a creamy pint of Guinness alongside these brownies, I prefer topping them with this Guinness frosting instead!
It’s creamy, lightly sweet, and flavored with more of the reduced Guinness, espresso powder, and vanilla.
The flavor is hard to describe but completely delicious—espresso-like with subtle malty, caramelized notes from the stout.
These Guinness brownies would also be fantastic topped with vanilla ice cream, homemade whipped cream, or the mocha whipped cream from my flourless chocolate cake recipe.
No. Guinness brownies do not taste strongly like beer. Instead, the stout enhances the chocolate flavor with subtle roasted notes similar to coffee or dark caramel. The result is a richer, deeper chocolate brownie rather than a beer-flavored dessert.
Classic Guinness Draught stout works best for baking brownies. It has a smooth, slightly roasted flavor that complements chocolate. Extra stout or other dark stouts can also work, but they may produce a slightly stronger malt flavor.
No. Reducing Guinness concentrates its flavor while removing excess liquid. Brownie batter can easily become too thin if extra liquid is added, which can lead to cakey or gummy brownies. Simmering the stout first ensures the brownies stay dense, moist, and fudgy.
Yes. Although the brownies contain Guinness, the alcohol content is reduced during simmering and baking. If you prefer an alcohol-free version, you can substitute a stout-style nonalcoholic beer for a similar flavor.
Brownies are done when a toothpick inserted in the center comes out with a few moist crumbs—not coated in wet batter (underbaked), and not completely clean (overbaked). Overbaking can make brownies dry, so it’s best to remove them from the oven when the center is just set.
Guinness Brownies
- Prep Time: 45 minutes
- Cook Time: 35 minutes
- Total Time: 3 hours
- Yield: 16-20 brownies
- Category: Brownies
- Method: Baking
- Cuisine: American
Description
These Guinness brownies are made from reduced Guinness Stout. They’re fudgy, rich, and topped with espresso- and Guinness-infused frosting!
Ingredients
- one (11.2–12-ounce (330–355ml) bottle Guinness Draught Stout beer
- 3/4 cup (12 Tbsp; 170g) unsalted butter
- two 4-ounce bars (226g) semi-sweet chocolate, coarsely chopped*
- 1 and 1/4 cups (250g) granulated sugar
- 3 large eggs, at room temperature
- 1 teaspoon pure vanilla extract
- 1 cup (125g) all-purpose flour (spooned & leveled)
- 1/2 teaspoon salt
- optional: 1/2 teaspoon espresso powder
Guinness Frosting
- 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
- 2 cups (240g) confectioners’ sugar
- 2–3 Tablespoons reduced Guinness (from step 1)
- 1 teaspoon espresso powder
- 1/2 teaspoon pure vanilla extract
- 1/4 teaspoon salt
Instructions
- In a small saucepan, bring the Guinness to a boil over medium-high heat. Once boiling, reduce to medium heat and allow to simmer until reduced down to 2/3 cup (160g/ml), about 12–15 minutes. Set aside to cool for at least 10 minutes. You will use 1/2 cup (120g/ml) in the brownies and the rest in the frosting.
- Preheat the oven to 350°F (177°C) and grease a 9-inch square baking pan or line with aluminum foil or parchment paper, leaving an overhang on the sides to lift the finished brownies out (makes cutting easier!). Set aside.
- Place the butter and chopped chocolate in a large microwave-safe bowl. Melt in 30-second increments, whisking after each, until completely smooth. Whisk in the sugar and 1/2 cup (120g/ml) of reduced Guinness until completely combined. Whisk in the eggs and vanilla extract. Finally, whisk in the flour, salt, and espresso powder (if using). The batter will be thick and shiny. Pour/spread evenly into prepared pan.
- Bake for 32 minutes, then test the brownies with a toothpick. Insert it into the center of the pan. If it comes out coated with wet batter, the brownies need more time. If there are only a few moist crumbs, the brownies are done. Keep checking every 2 minutes until you have moist crumbs. My brownies take about 35 minutes.
- Remove from the oven and place on a cooling rack to cool completely in the pan before frosting or cutting.
- Make the frosting: In a large bowl using a handheld or stand mixer fitted with a whisk attachment, beat the butter on high speed until completely smooth and creamy, about 2–3 minutes. Add the confectioners’ sugar, beating on low at first then increasing to high speed. Once creamy and combined, beat in 2 Tablespoons of reduced Guinness, the espresso powder, vanilla extract, and salt. Taste. Add the remaining reduced Guinness if needed. If you want the frosting a little thinner, beat in a splash of milk.
- When cool, lift the brownies out by gripping the parchment overhangs and transfer to a cutting board. Spread frosting over cooled brownies. Use a sharp knife to cut into squares.
- Cover and store leftover brownies at room temperature for up to 1 week.
Notes
- Make Ahead Instructions: Freeze frosted or unfrosted brownies up to 3 months. Thaw overnight in the refrigerator then bring to room temperature before serving.
- Special Tools (affiliate links): Electric Mixer (Handheld or Stand) | Glass Mixing Bowls | Whisk | Saucepan | 9-inch Square Baking Pan | Icing Spatula
- Chocolate: You can find 4 ounce chocolate baking bars in the baking aisle. I like using Ghirardelli brand or Baker’s brand. You can use 8 ounces (heaping 1 and 1/3 cups) of quality chocolate chips instead, such as Ghirardelli brand.
Reader Comments and Reviews
I had my doubts when I thought I may have undercooked this and the frosting was not like any frosting I’d made before but these were SO good! It’s pretty easy and quick to throw together. I’ll definitely be making these again.
Loved the texture and bitterness of the brownie! My only adjustment was melting the butter in the baking pan till very lightly browned and then pouring that over the chopped chocolate (I used 65% Cordillera – look them up, much better choice for the environment and working conditions!)
For me though, the frosting was just not needed. It was sooooooo sweet, and I did add a Tbls of cocoa to try to counteract it, but who needs the frosting really? The brownies are just fantastic as is.
Go raibh maith agat!
Hey there, do you think these would do alright if I made them in a muffin tin with a shorter cooking time?
Hi Katherine, we can’t see why not!
I have a bag of Ghirardelli melting chips on hand…can I use those for the chocolate part? Just trying to avoid a trip to the store. Thanks.
Yes, those should work. Enjoy!
I want to bake today and frost tomorrow, can the reduced guinness sit overnight before going into the frosting?
Definitely! We would refrigerate overnight and bring back to room temperature before using in the brownies and frosting.
Am I the only one having trouble “Saving the Recipe”? Not a problem with saving your other recipes. Just wondering.
Hi Elaine, We tested it and it seems to be working for us. Let us know if you are still having problems!
I love this brownie recipe! I’m a bit of a chocolate freak, so I was wondering if I could make a chocolate version of this frosting. I was thinking about adding unsweetened cocoa powder to it. What do you think
Hi Niki, you can certainly try adding some cocoa powder to the frosting. You’ll likely need to tinker with the confectioners’ sugar amount a bit. Let us know what you try!
I love the taste but I made a bit of a mess when trying to slice into squares. Do you have any tips on how to get clean cuts for a pretty presentation? Thank you!
Hi Nicole, Using a super sharp knife and wiping it clean between cuts will help!
My sister-in-law told me to cut brownies with a plastic knife … don’t know why, but it works like a charm every time!!
Forgot to leave a five star rating in my review!!!
The brownies turned out fantastic! Not too sweet with the right hint of tasty Guinness. My icing turned out grainy no matter how long I beat it. Is there another way to fix or avoid grainy icing? Thanks for the recipe!!!!
Hi Tracey, we’re so glad they were a hit! For smooth frosting, first make sure to beat the butter until creamy before adding the rest of the ingredients. Second, sifting your confectioner’s sugar can prevent the frosting from being grainy. Hope this helps for next time!
No matter what I try, glass, metal, aluminum foil, parchment paper, no lining, I can’t cook these brownies. The outside will burn but the inside will be raw and they are in the oven for 3 hours. I made them once and they were amazing but I can’t get the recipe to work again and am very disappointed. Any advice?
Hi Sara, we’re happy to help troubleshoot. Are you making any changes to the ingredients by chance? It’s normal for the edges of brownies to bake quicker and be a bit different in texture from the middles, but if you find them baking too quickly then you can tent the edges of the pan with aluminum foil while keeping the middle exposed. This will allow it to continue baking through. Hope this helps!
Great recipe! I subbed 26 grams of the semi-sweet for unsweetened chocolate. FYI to the team, as with many products, Guinness has “shrunk” their bottles of stout to 11.2 ounces instead of the old 12 ounces. You may want to adjust your recipe accordingly.
Omg! Best brownies ever!
These are fantastic! Everyone I’ve shared them with LOVES them and wants more. I doubled the last batch I made and put in a 9×13. But, in my opinion, it really needs to go into a 10×15. The brownies were really thick and became more cake like in the 9×13. Technically, the math works out for that. FYI to anyone who wants to double the recipe.
This turned out just ok, I followed the recipe exactly including espresso powder, and used ghirardelli chocolate. The brownie texture is semi-cakey, lacks crisp edges, and doesn’t have an intense chocolate flavor. The frosting is aggressively sweet. Overall it’s not bad but not one I’d make again.
Made these after a friend shared the recipe. Definitely recommend using really good chocolate – you will taste the difference. I also used non-alcoholic Guinness and it was great. Made into a giant brownie for a bday cake. And made some for a party and people asked to take them home. Really good! The frosting recipe made way too much frosting but it’s delicious. Can I freeze frosting?
Sally’s I loved the brownie recipe & it tasted great! I was not keen on the smell of Guinness in the icing. Don’t know why, it just got to me! I’ve used Guinness in cupcakes, too & love it. Anyway, I am going to substitute Bailey’s next time in the icing.
Best Brownies ever! Made these for St.Patrick’s Day for a festive treat (love me some Guinness too) and these may be my new go to brownie recipe. I couldn’t stop eating them. Don’t hesitate to try these anytime of the year! Thanks Sally!
Yummmmmm! Slightly cakey, but more fudgy, deep chocolate flavor, very rich. Frosting was perfection.
I made the Guinness brownies twice around St Patrick’s Day. My husband finally begged for mercy (trying to control his weight). They are absolutely amazing! Gave some to several friends; everyone said they were the best brownies ever. Thank you!
These are delicious, and the house smells wonderful while they are baking. What is the best way to freeze some of the unfrosted brownies?
Hi Rita, You can freeze frosted or unfrosted brownies up to 3 months. Thaw overnight in the refrigerator then bring to room temperature before serving.
Thank you – I almost forgot to leave my 5 star rating!
Can’t wait to try this recipe!! Could I sub black cocoa powder for chopped chocolate? If so how much should I use? Love all your recipes!!!
Hi Tracy, you really need pure chocolate for this brownies recipe – swapping for cocoa powder would require a bit of recipe testing. Hope you enjoy the brownies!
These were delicious! Somewhere between fudge and cakey. Mine were done at 30 minutes. I cut the frosting recipe in half – that was perfect for us. Highly recommend!
Very good! I used 72% dark chocolate from Trader Joe’s and Chocolate Stout, as that is what I had in the house. Not overly sweet but very rich!
Happy St. Patrick’s Day…Guinness Brownies for dessert tonight. I snuck a little corner and they are delicious. Frosting is especially good. I did add toasted pecans to the batter.
The best Brownies I’ve ever had. The Guinness and Espresso truly complement the chocolate in this recipe. We will be making these over and over again. A perfect treat for this St. Paddy’s Day dessert.
Love this recipe! Made these brownies a year ago St.Patricks Day, now have people clamoring for it this year…move over Irish soda bread, got a new family favorite!
Brownies are in the oven now! They smells amazing!! Can I add cocoa powder to the frosting for a chocolate frosting? If so, do you know how much?
Absolutely! I’m sure 2 Tablespoons would be plenty.
These are always a hit with my friends and family on St. Patrick’s Day! They are perfect! And if you’re worried about them being overly sweet with the frosting, don’t be! Thanks for an amazing and easy recipe.
I’ve just made your Guinness Brownies for my TWO St. Patrick’s Day parties…doubled the recipe… doubled the icing! No matter the errors/tweaks I made, these were to die for. I’ve found a new proven baking friend! Thank you! (And, my Guiness was the new O% alcohol…bought by mistake…{should have searched for a single bottle of Guiness STOUT, instead of the DRAGHT, but sure doesn’t seem to have made too much of a difference…next time I’ll use the real STOUT to taste the difference}. Who knew delicious velvety Guinness could simmered down to a pot ‘o’ gold!!!