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 don’t have espresso powder, I’ve looked in my local grocery stores and can’t find it there either. Can I use instant coffee instead? If so, should I maybe make it more like powder? Looking forward to making them for St. Patrick’s day tomorrow, along with Guinness infused Irish lamb stew and soda bread!
Hi Bobbi, If you have instant coffee you could use that instead, but it isn’t quite as strong as espresso powder. You can increase the amount or simply expect a milder flavor. Or you can simply leave it out. Let us know how they go for you!
I ended up using 1 1/2 tsp instant coffee in the batter and 1/2 tsp in the icing. Turns out my reduction didn’t yield quite enough for the icing, so I put a splash of the Guinness from the can in, and OEMGEE! It’s fabulous! Thanks for the recipe!
To cut down on time, how would this recipe change if I used a pre-made brownie mix? I wouldn’t change the frosting, and I would want to use the espresso powder and Guinness in the mix. Thanks!
Hi Alexis, we’re unsure of the exact amount of Guinness reduction you’d need to add to a box mix. You could try replacing the liquid called for with the reduced Guinness, and then add espresso powder.
Best brownies ever! I used dark chocolate chips and they came out great. Decide to skip the frosting, though it might be too sweet. This will be my go to recipe for brownies!
I made these brownies a few days ago for my mother in law’s birthday. She loves chocolate and Guinness is the only beer she drinks. Omg these were such a hit! The best brownies I’ve ever had and brownies are my favorite dessert. The frosting is perfect, light and fluffy and not too sugary. I was going to make them again today for my husband to take to his fire station but I only have 1 Ghirardelli chocolate bar. I have nestle chocolate chips but I am not sure if they would work. Has anyone tried using them?
Hi Catherine, you can use 8 ounces (heaping 1 and 1/3 cups) of quality chocolate chips instead, such as Ghirardelli brand. We haven’t tested Nestle to know how well they will work. We’re glad to hear the brownies were a hit!
Never underestimate the capacity of readers to make a mistake—I reduced the Guinness to 2/3 cup snd then put the whole amount into the brownies instead of saving 1/3 cup for the icing. They took extra time to cook, needless yo say, which was my hint. I haven’t tried them yet—fingers crossed they will be great anyway.
Any tips on how to cut the brownies in the beautiful squares without being crumbly?
Hi Karla, using a super sharp knife and wiping it clean between cuts will help!
I can’t wait to try this recipe! Would this work using vegan butter and chocolate? Preparing for a group that includes dairy free folks!
Hi Isabella, we haven’t tried those swaps so we’re unsure of the results, but let us know if you do!
This will be year 3 or 4 of making these to celebrate St Patricks day in our house. I look forward to it, they are 2 thumbs up. Thank you for this jem Sally
Hi! Can I add more than 1 tsp of espresso powder? If so, how many more tsp can I add without ruining this dessert? Thanks!
Hi Cathy! You can add espresso powder to taste, we probably wouldn’t recommend more than 1 Tbs, but let us know what you try!
I’ve always loved this recipe, and I make it all the time in fact I now use it for Brookies. I was wondering if I could swap the Guinness for Baileys? would I use the same 1/2 cup or less e.g. 1/3 cup instead.
Hi Abby, because Guinness and Baileys are so different in consistency, we aren’t sure how these brownies would turn out, or what amount you’d need to use. Better to try searching for a specific Baileys brownie recipe. But we will keep this request in mind and may develop a recipe for Baileys brownies in the future!
Looks delicious! I want to make these for a St Patricks’ work event. Does the alcohol in the Guinness cook off while it reduces?
Hi Cameron, the alcohol is cooked out when the Guinness is reduced on the stove, but feel free to make the best decision based on who you are serving these to. Hope they’re a hit!
Can I use finely ground espresso instead of espresso powder?
Hi Tracy! No, they are not the same. Best to stick with instant espresso, or instant coffee in a pinch (or you can leave it out!).
I’ve been dying to make this recipe, plan to do so this weekend. One question – for me, a brownie needs nuts; don’t want to spoil them and none of the comments mentioned adding them…but I’m sure tempted. Any issues?
Hi Jenny! You can definitely add chopped nuts if you would like.
Can I use semisweet chocolate chips/mini chips instead?
Hi Mel, you can use 8 ounces (heaping 1 and 1/3 cups) of quality chocolate chips instead, such as Ghirardelli brand, instead of the baking chocolate bars.
I use freshly ground espresso in lots of baking recipes, and it’s always delicious.
Adjust your grind depending on the application. For cupcakes, I use a slightly coarser grind. For frostings, creme brulee and angel food cake, I grind very fine, to where the flecks from the vanilla bean paste and the ground espresso look somewhat similar.
Experiment and enjoy! You can’t really go wrong with any combination of espresso and chocolate!
I was definitely skeptical about the taste of the Guinness, but you have to trust the process with this one. SO delicious, they taste like bars of fudge. Thanks for the recipe : )
Hey there! I wanna make these but all I have is cocoa powder. What would be the best ratio for that?
Hi Meg, you really need pure chocolate for this brownies recipe – it yields the best flavor!
I made these brownies a week ago and they were great. Has anyone had experience with bake time if you double the recipe, and use a 9 x 13″ pan?
Super delicious – was nervous at first. My beer reduced down too much within 12 minutes, so I only had 1/2 cup. I used an oatmeal stout from Trader Joe’s. Since I didn’t have beer for the frosting, I used Bailey’s Irish Cream. I will note, I halved the frosting and felt that was enough for the pan. Especially since we got a lotttttta buttttah in the batter.
Would certainly make these again, maybe omit the espresso powder from the frosting and add a bit more to the batter.
Do I keep these in the fridge?
Hi Kate, We are so happy you enjoyed these! We usually cover the brownies and store them at room temperature for up to a week but you can certainly store them in the refrigerator also.
I made these for St. Patrick’s Day this year and they were a huge hit with my family. We have some beloved brownie recipes already, but judging from the response I got, these brownies will be at the top of the list. I doubled the recipe and it worked out great. The espresso powder really added to the flavor. Thanks Sally!
Made these for St Patrick’s Day & everyone loved them! Guinness flavour was subtle, complementing the dark chocolate I used perfectly (I prefer ‘less sweet’ so dark chocolate was perfect). Didn’t have espresso powder so substituted Kahlua liqueur for a bit of the condensed Guinness in both the batter & icing to give that coffee flavour. Worked perfectly! Thank you for the recipe
What would the quantities be for a 9 x 13 pan?
Hi Stacey! You can double this recipe for a 9×13 inch pan. I’m unsure of the exact bake time.
These brownies were easy to throw together and were very delicious, BUT…I took them out of the oven after 36 minutes—when the toothpick came out with crumbs as described, and the top seemed done. No settling occurred after they cooled so I went ahead and frosted them. The first three pieces were perfect (though for my taste, there was too much frosting—we loved the taste of the frosting), but beyond the first row, the brownies looked like raw brownie dough. It was the strangest thing. I was going to toss the whole pan, but then thought, what do I have to loose? I scraped most of the frosting off, and baked them for 30 more minutes and they were finally done. I tossed the frosting and the frosting that I couldn’t scrape off baked and looks like of cool and added a tasty sweet topping. I dont think I will make these again unless I add more flour and bake at a higher temperature.
Made these for my St. Patrick’s day ladies bridge party. I never expected them to be so good since I am not a beer drinker. Huge success. I made several days ago and froze, and they tasted better than the day I made them. Definitely 5 stars!
I just made these for St. Patrick’s Day and they are delicious. I don’t normally like frosting, but the frosting was a nice addition to the brownie. They are equally as delicious without the frosting. This recipe is a keeper and not just for St. Patricks Day! 😉
Really great recipe- including the frosting which I don’t normally bother with. Half the frosting was perfect for a lighter frosting contingent. Don’t skip the espresso powder in the brownies or frosting!
Oh my gosh! Just made these for St Patrick’s Day, the best brownies ever♥️
These are delish! How do you freeze a frosted brownie without smashing the frosting? And if I wait to frost, can the frosting stay in the fridge and for how long?
Thanks!
Hi Alyssa, We are happy you enjoy them! You can either freeze them in a container where the frosting isn’t right against the lid. Or you can freeze them uncovered for 15-30 minutes until the frosting is “set” and then wrap them for a longer freezing time.
Everyone who tasted these loved them! Great recipe!
Never expected to love these as much as I do! “Inherited” two bottles of Guiness and this was the best use ever. Fudgy but not goopy, great texture, reduced Guiness and espresso powder add great depth of flavor. I halved the frosting as I wanted more of a sweet glaze rather than full out frosting. Thank you for another great keeper!
Best brownies I ever made … EVER … seriously! These are phenomenal. I don’t drink beer let alone Guinness, but something made me grab a six pack of Guinness Extra Stout, and I’m sure glad I did. The combination of the reduced Guinness and the espresso powder is an unbelievable combination. I made no adjustments in ingredients or baking time. These baked up exactly as shown in the recipe. The best part … my husband won’t touch the Guinness, so it is ALL mine for more baking! Thank you, Sally, for the perfect recipe.
These were svery delicious. My hisbnd said they are a winner, I never had had Guiness before so I will either have to drink 5 bottles or make 5 more pans of brownies. I used an 8 x 8 pan and they took about 40 minutes.
I made these for my Guiness loving BF. He ate 3 brownies in one sitting. He commented that the frosting is the same color as the head on top of the Guiness when poured in a glass. My brownies were done in 30 minutes and were cakey, not like fudgy, so I was happy. Not very sweet so the frosting enhanced the brownie. BF said he’s going to eat the next piece with a glass of Guiness instead of milk.
Great recipe!! I was lazy and used my favorite box brownies adding melted butter (instead of veg. oil), 1 tsp. espresso powder, and 1/4 c. reduced Guinness (since my box only needed that much liquid. I made the frosting per your instructions.. OMG…these were delish! Thank you!
I live at 5300 ft elevation. Is there an altitude adjustment to the recipe? Thank you
Hi Lori, I wish we could help, but have no experience baking at high altitude. Some readers have found this chart helpful: https://www.kingarthurflour.com/learn/high-altitude-baking.html
I made the recipe with great success with these small alterations. I added 1 tablespoon of flour and 12 minutes to cooking time. It’s possible that a higher temperature would also have made the recipe come out right.
Thanks for the tip, Lori. I’m making these right now at 5280 elevation and I will follow your instruction.