If you love rich chocolate desserts, these Guinness brownies are about to become your new favorite. Theyโre 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!
Before you worryโthese brownies do not taste like beer. Instead, Guinness stout enhances the chocolate flavor with roasted, coffee-like notes and a hint of caramel sweetness. Itโs 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 brownies.
- Creamy Guinness frosting: Light, smooth, and slightly espresso-forward with subtle malty caramel notes.
- A wonderful dessert recipe for St. Patrickโs 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 brandโI 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. Itโs 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 chocolateโjust like these seriously fudgy 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.
Hereโs 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 bakingโless 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 youโve 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!
Itโs creamy, lightly sweet, and flavored with more of the reduced Guinness, espresso powder, and vanilla.
The flavor is hard to describe but completely deliciousโespresso-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 crumbsโnot coated in wet batter (underbaked), and not completely clean (overbaked). Overbaking can make brownies dry, so itโs 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 (11.2โ12-ounce (330โ355ml) 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
- 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 12โ15 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 350ยฐF (177ยฐC) 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:ย 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 2โ3 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:ย 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
These took an extra 20 minutes to approach being set enough to take out of the oven. I am a Guinness snob, so I used Guinness stout. The drought stout. Then I see a photo of the Guinness EXTRA stout. Thatโs a whole other animal. If that was what was to be used it needs to be specifically said the EXTRA STOUT. Not the drought with the nitrous, which is the original Guinness. This is the only thing I can imagine that made my brownies all wet.
Hi Carey, any Guinness is fine here. Did you reduce the Guinness? (see step 1). If you didn’t reduce the Guinness, that would add too much liquid to the batter.
I donโt have espresso powder – could instant coffee be used instead? That is what I usually keep on hand for baking.
Yes!
Hi Sally & Team, can this recipe be doubled using 9×13 pan? Thank you
Hi GayLynn, you can absolutely try doubling this recipe for a 9ร13 pan. Weโre unsure of the exact bake time โ use a toothpick to test for doneness. If there are only a few moist crumbs, the brownies are done.
I made these in a mini muffin pan, and omg are they delicious! The frosting was definitely coffee forward due to the espresso powder, and now I’m thinking of different things I can put the leftover frosting on. So good!
We love these brownies and have had them for the last five St Paddyโs day – this year Iโve had to cut out both wheat and eggs and Iโm trying to find substitutes for both to still have these this year! Iโm planning for King Arthur gluten free all purpose and then a flax seed egg substitute, but do you think thereโs a better alternative?
Thanks!!
We haven’t tested those substitutes ourselves, Caitie, but let us know if you do!
Hi Sally! I have loved many of your recipes and am excited to make these brownies for an event on Saturday. I have two questions for you:
(1) I do not have a 9 inch square pan, but have a glass pan that is 8 in x 8 in x 2 in. How should I adjust the baking time?
(2) Will these brownies stay fresh if I make them on Thursday night and refrigerate them after cooling? Or would you suggest making them closer to the event (Friday night or Saturday morning)?
Hi Elizabeth, an 8-inch pan is a bit too small. The brownies would be extremely thick and have a difficult time baking through. You could fill your pan about half way and then discard the extra batter, or make some mini brownies in a muffin tin. You can store the brownies at room temperature for up to a week, so they should be fine if baking two days in advance.
Made these and they were so delicious and fudgy!
I’ve been making this recipe for a good year now and they are still a crowd pleaser! Every birthday so far everyone wants the guinness brownies!
First time making brownies from scratch. Not sure if user error but I used an 8×8 instead of a 9×9 baking pan because that was all I had. It didn’t seem like a big difference to me, but my brownies even after 35+ mins in the oven are still suuuper fudgy texture bordering on not done all the way through, but then crumbly on the edges. The flavor is amazing and really rich especially loved the frosting recipe. But not sure if I went wrong w pan size or what, they are so fudgy and dense that you can’t have more than a bite or two and the corners were falling apart.
Hi Len, the smaller pan size is likely the culprit here. By using a smaller pan, there was too much batter for the brownies to bake through properly which caused the dense, unbaked texture you mention. Thank you for giving these a try!
Made these for a party of beer brewers using home brewed Irish stout instead of Guinness.
These brownies are so rich and delicious! Our beer community highly approved!
I was originally going to skip the frosting but glad I didn’t. That mocha maple-y flavor added so much. Will definitely be making these again! Thank you!
Everyone loves this brownie!! Rich and decadent so small pieces are perfect. I have tried recipe 4 times and everyone loves them. I have tried different dark chocolates from Trader Joes including one with nuts. One with coffee beans all chopped up. Think I prefer without nuts but worth a try. Thanks!
Was really impressed with this recipe. Very easy and tasty. I didnโt bother with the frosting. I used a 72 percent dark chocolate.
I made these for St Patricks Day and everyone loved them. My husband still can’t stop talking about how great they are and keeps dropping hints for me to make them again. If you love brownies and want to elevate your game this is the perfect recipe. Will definately be making again. Thank you for all the delicious recipes. They are always a giant hit!!
They didn’t set! 40+ minutes in the oven and still runny. I triple checked the ingredients and everything. What happened!?
Hi Helen, Are you making any changes to the ingredients by chance? Itโs 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!
Long time baker โ these were awful. Horrible flavor and aftertaste. After two bites, they went in the garbage.
Winner. The brownie with the frosting is a good combination. The beer and espresso are interesting components. It was a popular at our neighborhood party!