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
Best brownies I ever made (including my mother’s go-to version). Very rich and creamy with a rich, bittersweet edge. I made them for a St. Patrick’s party and they were a crowd favorite.
This recipe was outstanding. I think the tip to boil down the stout is genious! BTW, quite by accident, I boiled down 14.5 OZ of stout, not the 12 OZ you called for. Might have intensified the flavor, but this was for the better! First time using your site, and will be following more of your recipes in the future.
Didn’t have a 9×9 so went with a 7×11 since it was only 3 extra square inches. Bake time was the same. These turned out perfectly, although I admit using regular stout by accident (forgot to check for extra stout). Mmmm. Great treat to kick off the St. Patrick’s Day weekend at work!
I bought a 22oz of Guinness. When I make the brownies, I will still have another 12 oz, I really don’t want it to go to waste. Do you think if I reduced the other half, do you think it would keep in the fridge? Or should I just keep the bottle in the fridge and reduce it another time?
Hi Madeline! You can store extra reduced beer in the refrigerator. Not exactly sure how long, but a few days would be fine!
Hi Sally! These are SO GOOD–they have replaced the Chocolate Stout Cupcakes from King Arthur Flour as my go-to recipe for a chocolate item that’s out of the ordinary. While I liked thos cupcakes I never felt that the chocolate flavor was very intense. I do still use the chocolate stout though instead of Guinness–sort of a specialty item, I guess, but I’ve always been able to get it at a regular liquor store–the brand I always find is Young’s Double Chocolate Stout. The cans are 14 ounces, so I just boil it down to the amount you say-even more flavor! And what a genius, genius idea to boil it down in the first place. Also, b/c I usually am making these for a reception or party, I make them in min-muffin tins, baking them for about 15 minutes. I doubled your recipe and that made 96. And the frosting is genius too!
Hey Sally,
I was hoping to make these for a St. Patrick’s Day party and wanted to double the recipe so I would have enough. I was thinking of using a 9″x13″ pan and increasing the baking time somewhat. Have you tried this before?
Yes, you can double them!
I have one question. Since the beer was reduced on the stove, would the frosting not be alcoholic? I want to send some of these with my husband to work, but I don’t want him sharing these with his coworkers and getting in trouble.
If you heat it long enough the alcohol will evaporate, but please do your research and make the best decision for you!
Good-morning Sally, I have a confession to make, have made so many of your recipes and have received rave reviews from family and friends; sometimes I think I should tell everyone it is thanks to Sally too LOL. My question – I have made these brownies countless times and they are the best. I prefer a « cakey » brownie, do you think I could add baking powder to the mix?
Hi Lucille! Thank you so much for baking and trusting my recipes. I appreciate it so much. Baking powder would certainly lift the crumb to yield a cakey Guinness brownie. Let me know how they turn out.
This might be a crazy question- but does the expresso powder have to instant or can I use the expresso powder I would put in my coffee pot?
Is stout or extra stout recommended? Thanks.
Hi Iris, you can use either.
Made these brownies for my coworker’s birthday this week and EVERYONE raved about them! The brownie part had me worried a bit because the batter looked thin after I mixed it up… and during baking it developed a weirdly cracked top but my oven sucks so it could be at fault. The icing definitely put it over the top! I had some left over so I made a couple of plain vanilla cupcakes (four, to be exact) and my fiance and I devoured them, lol. A keeper, without a doubt!
I just made theses brownies and they are really tasty for breakfast! My taster had to give his opinion on the frosting as I ran out of icing sugar after the stores were closed. They tasted fabulous naked. So unctuous and rich!! With this frosting, my colleagues are going to be in for a treat. You have set my reputation with the Irish car bomb cupcakes and this will really give me star power now. Thanks Sally.
You were right about needing to make two batches! I made these last night and they are already gone! My family was a little bit skeptical about them tasting too much like beer, but they LOVED them! These brownies are so moist, fluffy, AND fudgey! Didn’t know it was possible to have all of these textures at once, but it is! And it is fantastic. Definitely going to make them again- they are truly a unique and wonderful treat!
These brownies were fabulous! The tip to line the pan (I used foil) made it so easy to lift them out and divide in half – brought half to a friend’s home on St. Patrick’s day and the other half to lunch the next day at our daughter’s. Everyone loved them. Definitely a keeper
I have made these brownies twice and they are delicious. I made them once for a St. Patrick’s day event at work and one for a St. Patrick’s Day dinner.
I had one question though, the frosting after it sits for a bit gets white dots. I’ve made them twice and it happened both times. I thought maybe it was the salt but not sure. Have you run into this before? I use the recipe for the frosting exactly as stated.
Made these today… wow!! So fudgy and delicious. Will be making this again for sure!
Absolutely delicious! I made these yesterday for St. Pattys Day and my family loved them They are definitely a keeper!
Best brownie recipe I’ve ever made. Weighed all ingredients & followed your recipe to the letter. Also appreciated your link to an explanation of why careful measuring is key to successful baked goods. Again, these are fantastic! Thank you!
Made this for St Patrick’s Day. The frosting was to die for! Absolutely delicious the next day as well. Thanks for the great recipe, Sally!
Sally! Delicious brownies! We had them tonight after my Irish dinner (boiled corned beef..trick, press meat when it comes out of water), roasted potatoes and carrots, sautéed cabbage and leeks, and homemade whole wheat Irish Soda Bread! Yummy St. Patrick’s Day!
Oh my goodness these are AMAZING!
I am making these as we speak, they smell AMAZING! I’m making the frosting and it looks runny (however is tastes delicious!!), any idea what I did wrong?
Perhaps the butter is a little too soft? No worries there, it should still be great. How does it taste today?
OK, these are the BEST brownies I have ever had. My husband liked them so much that he took half the pan of brownies with him to share with a couple teachers at his school. The frosting was fabulous. I will bake these even when it’s not St. Patrick’s Day!
I just made these for a St Paddy’s Day party tomorrow. I want to just eat them all right now! So so good. Thank you Sally for all your great recipes! 🙂
Wow! I made these today and they are insanely good! I was one of the people who begged for a Guinness brownie recipe a few weeks back. This has definitely replaced my former one (as I thought it would). The texture of these brownies is unreal. What really set it apart for me was the Guinness buttercream. This will go on the St. Patrick’s Day tradition list for sure. Thank you so much for this recipe! Also (for people who read comments for tips) I used an 8×8 pan (it is all I have) and it took around 45 minutes. I started checking at 35. I like ultra thick brownies so this was perfect!
My daughter and I made these last night and the are wonderful! And the looked just like your photographs! Thanks!
Just finished making these. Amazing! I didn’t have espresso powder and these are still in the top brownies I’ve ever eaten. My coworkers are in for a treat tomorrow!
Hi Sally, is the espresso powder the instant type or just ground coffee powder? Thanks!
Hi Connie, it’s instant espresso powder.
HI Sally -What would you say is the baking time for an 8X8 brownie pan instead of 9X9? I’ve had great success with your recipes; this one is my agenda for tomorrow!!
Hi Shannon! They’ll take awhile in a smaller pan. I’m unsure of that exact time, but use a toothpick to test for doneness. A few moist crumbs are OK, but no wet batter.
I’m surely in the minority but I hate the taste of coffee.
No problem if I leave it out?
Hi Ems, yes, it’s optional.
What can I substitute beer with? Love the photos!!
I recommend the chewy fudge brownies 🙂
I made these last night, but dairy free and they still turned out great! The Guinness took longer to reduce also because I live above 7000 feet.
Sure can! The brownies will taste extra dark.