How to Brew a Black Forest Cake Pastry Stout

by Karl S Updated on September 2, 2023

Hello! Guess what? It’s pastry week! That’s right, it’s pastry week and around this time of year, pastry stouts are popping up everywhere. The cool weather calls for big ABV with a sweet finish, perfect to warm the bones.

Have you ever brewed one before?

I thought I’d give it a go, putting my own spin on it by infusing the flavors of chocolate and cherry in this black forest cake style. I’m Trent Musho and this is the Bru Sho. Let’s brew a Pastry Stout.

Pastry stout, if you’re not familiar, is a stout that’s high in ABV and heavy with adjuncts that are reminiscent of a dessert or can even be made with said dessert. In my eye, a pastry style has a thicker mouth feel, a sweet finish, and a strong alcohol content anywhere from 8% or higher.

These beers are not an official style of beer and are rather new, so there’s a lot of fudging with ingredients you can do. See what I did there?

Some people see pastry stouts as a way to throw in a buttload of their favorite dessert right into the mash and call it beer, but in my opinion, that really is enough to give the flavor you’re looking for. That’s why today, you won’t see me throw in a whole cake but instead use beer ingredients with a few select adjuncts to give the impression of a black forest cake.

A black forest cake is a traditional German dessert made from chocolate sponge that’s soaked with cherry liqueur or syrup, then layered with whipped cream and topped with more cherries. How could this not be made into a beer, right?

Well, that’s exactly what I set out to do. Let me show you how I did it.

First, a huge thank you to the partners that support this channel: Northern Brewer who supplied all the ingredients for this brew, and Claw Hammer Supply, which I’ll be brewing on their electric 120-volt system. I have links in the description for both of these if you’re interested in knowing more.

And don’t worry, if you don’t have an electric system, you can deliver the same recipe on a simple brewing bag setup like I’ve shown many times before.

Let’s start with the grain bill, which is one of the more complex ones I’ve done in this channel. 34% pale malt, 34% pilsner malt. These two will be our main fermentables, and I only mixed them up because I had both.

So, you could totally just pick one of these or mix at a different ratio. 21% flaked oats to really build up that body and mouth feel. 3% pale chocolate, this will give us a bit of color but also a good chocolate flavor. 2% Carafa, mainly just for the color. 1% Cara Munich for some added complexity and caramel sweetness.

And 1% roasted barley for that last bit of color boost and a roasty chocolatey goodness. The final 4% will come in the form of pure black cherry juice that I’ll add in later.

Before I even jumped in, I had a little bit of a hurdle to overcome. I designed this recipe to hit OG above 1.110, which means we’ll need a lot of grains, way more than I’ve used before and way more than I can fit in this 10-gallon kettle.

I think I had like 30 pounds of total grains here. So what I decided to do was break this into two mashes or what’s called a reiterated mash.

This is where I’ll take half of the grains and mash normally. Then, I’ll remove those grains from Mash 1 and add in the rest of the grains for a second mash using that wort as our strike water. This was a first for me, but to save some headache of removing the grains, I placed a brew bag inside the metal basket for Mash 1.

I added half the grains, excluding all the roasted grains, and used only half of the water. I mashed that at 158°F for 45 minutes.

This higher mash temperature should help promote more residual sweetness and a thicker body. After the 45 minutes, I lifted up the grain basket so I could rinse the grains with the remainder of the water.

I then lifted up and pulled out the bag, leaving behind just the wort and an empty basket, ready for the rest of the grains and Mash 2. The reason I’m saving the roasted grains until Mash 2 is because I don’t want to extract too much harshness, which can lead to ashy or acidic flavors in the beer. I want this to taste like chocolate, not like a cigar.

I let Mash 2 go for 45 minutes as well. After the timer went off, I pulled out the grains, and man, I got my workout this day!

To improve my chances of increased original gravity, I decided to boil this for 90 minutes to concentrate the wort.

At the top of the boil, I added 1.25 ounces of Warrior for about 53 IBU, and then let it rock for an hour and a half. This was probably one of the longest brew days I’ve ever had, but it was definitely worth it, since the OG was predicted to be so high.

I decided it would be best to plan this brew day the same day as I was taking up another batch so I could use the yeast from that beer to power this fermentation. This would ensure I had a strong yeast cell count to limit all flavors and make sure they could chew through all these sugars with ease.

So here’s the fermenter from the Ube beer that I made for Halloween. I did my best to keep things sanitary and keep the lid closed until it was ready. I didn’t rinse or wash the yeast. I just opened it up and then added in one of these jugs of black cherry juice.

Once the wort of the stout was cooled, I transferred it, splashing as much as I could to incorporate some oxygen, since we know big ABV beers need lots of oxygen.

I wasn’t too worried about the flavor carryover from the Ube. I mean, the main flavor profile of Ube is vanilla, which could totally work here, but I’m not sure how much of that will come through.

Speaking of big, the original gravity came in at 1.120. Whoo! I just closed the lid and let it ferment at 67 degrees for two weeks. While that fermented, I prepped a little tincture to boost those cherry and vanilla flavors that are iconic in Black Forest.

To do this, I bought a very expensive vanilla bean (I think this was like $15). Hey, I never said this was going to be cheap. And I also grabbed some cherry vodka, although I don’t know how much that flavor will carry over from the vodka, but I figured it wouldn’t hurt.

I split the bean lengthwise and then scraped out all the bits, adding it to a mason jar. I also chopped up the bean into smaller chunks and added them for good measure. I then covered it with some cherry vodka and let it infuse for the remainder of the fermentation.

By the two-week mark, all signs of fermentation had stopped and the tincture was looking nice and ready.

The final gravity came in at 1.053, which sounds super high, but is actually completely normal for high ABV beers, especially ones that are mashed at a high temperature like I did. This all means this pastry stout came in at 9.2 percent.

Taking a sample, it was dark, rich, and chocolatey. I was pumped to get into the keg. First, I strained my tincture, removing the vanilla bean bits, and then poured it into the keg. I then closed it up, purged with CO2, and transferred the beer.

You could totally bottle this and age it, which is what a lot of people do with their big stouts, but I was too excited to try it out.

Pouring the spirit, it looked absolutely apart: a deep, dark brown with a frothy tan head. The aroma had an assertive roasted cocoa with a sweet finish, and the cherry just barely poked through. When you take a sip, the thickness is immediately apparent, but not too thick, just the right amount of chewiness that lets you know that you should take this slow.

The chocolate is the hero here, but there’s cherry on the back end, especially when you exhale after a sip. To round it all out, there’s a bit of alcohol bite reminding you that this is almost 10 percent.

I’d be very curious to bottle some of this up and age it to see how the flavors might change over time. Overall, I’m super pleased with this one. I served it at a holiday party of the week and it was a major hit, especially as a sweet dessert treat.

I’d love to hear what kind of pastry stout you would make. Let me know in the comments with some ideas you have. And if you want to try an easy-sipping chocolate beer, then check out this s’mores lager I did. It’s the perfect combo of smoky chocolate with a crisp finish.

Frequently Asked Questions

What is a Pastry Stout?

A pastry stout is a type of stout beer that is high in alcohol by volume (ABV) and often includes adjuncts that give it flavors reminiscent of a dessert. These stouts typically have a thicker mouthfeel, a sweet finish, and a strong alcohol content, usually 8% or higher.

How is a Pastry Stout Recipe Different from a Traditional Stout Recipe?

In a pastry stout recipe, you’ll often find additional ingredients that are not usually present in a traditional stout recipe. These can include things like chocolate, cherry juice, or even vanilla. The aim is to mimic the flavors of a specific dessert, like a black forest cake in this case.

How Do You Brew a Pastry Stout with High ABV?

To achieve a high original gravity (OG), which leads to higher ABV, you may need to use a large amount of grains. The article describes a method called “reiterated mash,” where the grains are divided into two batches and mashed separately to fit into the brewing kettle.

What Does KBS Stand For in the Context of Stout Beers?

KBS stands for “Kentucky Breakfast Stout,” which is a type of stout beer that is often aged in bourbon barrels and may include flavors like coffee and chocolate. It’s not directly related to pastry stouts, but it’s another example of a stout with unique flavor profiles.

Can You Age a Pastry Stout?

Yes, you can age a pastry stout to see how its flavors develop over time. Many people bottle their high-ABV stouts and let them age to allow the flavors to meld and mature. Aging can be particularly interesting for pastry stouts, which have complex flavor profiles due to the various adjuncts used.