How to Brew Oatmeal Stout

by Steve Thanos | Updated: November 28, 2020

Oatmeal Stout, much like all other stout, derived from the porter heritage. It is said that oats were part of ancient brew kettles in Switzerland during the Bronze Age.

As other grains became more popular, oats became less and less favorable.

Seeing how well oats grew in England and Scotland, it seems fitting that reemerged in brewing recipes. 

During the mid to late 1800s, it was believed that adding oats to beer made it healthier. It was offered as a table beer commonly and even prescribed to nursing mothers and even ailing children. It was even believed to be a common remedy for sickness in general.

For many decades the oatmeal stout was lost. It was brought back into the spotlight in 1980 by the collaboration between Charles Finkel of Merchant Du Vin (an importer of foreign beer) and Samuel Smith Old Brewery in Tadcaster, England.

Also, homebrewers in the 70s and 80s, who grabbed onto anything English, gave the oatmeal stout a real boost. Famous beer writer, Michael Jackson in 1977 published his book, World Guide to Beer. This led Samuel Smith to revitalize the style. This gave the beer a new life and is now part of this styles’ history.

The simple addition of oats makes the oatmeal stout a truly wonderful beer style. With only five percent of the total grist made up of oats, this makes for a nice sweetness and smoothness. This helps tremendously considering oatmeal stouts are usually only 4-5% beers.

Adding more oats does make it possibly difficult due to its thick consistency when hydrated. The roasted grains counter balance the sweetness, along of course with the hop additions. 

Style Profile for Oatmeal Stouts 

Appearance

The color should be very deep brown to black..  A creamy-soft, long-lasting tan to brown head is expected for this style. Clarity should also be good. 

Aroma

Aroma often has a sweetness to it, almost cream-like. A malt aroma that is filled with roast and coffee notes is common. A nuttiness from the oatmeal can be recognized. 

Hop aroma, if present at all, should be earthy. Fruity aromas are common in the mild to medium-high range. Diacetyl in low quantities are acceptable. 

Mouthfeel

Body is medium-full to full. Medium to somewhat high carbonation. Mouthfeel should be smooth and velvety on the palate. The oatmeal may also contribute to an oli-like slickness. 

Taste

The oats can add an earthy, nutty, and  grainy quality. Dark grains balance the sweetness from the malts and may present itself as milk chocolate or creamed coffee. Hop bitterness is medium. Low to high fruity esters are acceptable, as is diacetyl. 

Food Pairing

Sweet stouts can be paired best with desserts. Anything chocolate will work; fudge brownies, German chocolate cake, pudding. It is perfect when making beer floats with ice cream and possibly some vanilla and coffee.

As for cheese pairings, thnk aged cheddar, Swiss, Brie, or Chevre. As a main course pairing, any game meats will pair well. Also, sweet stouts are great with gravies, hardy soups, roasts, barbeque, Mexican, or Asian dishes. 

Tips for Brewing your own Oatmeal Stouts 

Grain

Since the style is a traditional English style, British pale malt would be appropriate. Add anywhere from 60-80% of the grain to the grist. Like any stout, the specialty malts used are very important to a good recipe.

Munich malt, as much as 13% of the grist, will add nutty qualities to your beer along with adding character. A amalgamation of darker crystal, caramel, and/or cara-malts will provide caramel sweetness along with body to the beer.

The Cara malts will not contribute color like the crystal and caramel malts will. Keep these at a total of 10-15% of the grist. 5% of roasted barley is common, since there is less coffee character than say an Irish Stout. Chocolate and/or black patent can be added up to 5-10% of the grain bill. 

Hops

English hops, such as Fuggle and Styrian Goldings, and East Kent Goldings,  should be considered when brewing an oatmeal stout, with Fuggles at bittering and EKG for aroma and flavor. If American hops are your thing, then Cascade, Columbus and Willamette are commonly used in sweet stouts. 

Yeast

An English yeast is traditionally used in this style. Look for a yeast with a slight ester production. This will give the beer a mouthfeel and body you are looking for from this beer style. White Labs WLP002 English Ale, Wyeast 1318 London III or Danstar Winsor dry yeast are all good choices. Follow the temperature recommendations with any yeast that you pick. 

Mash 

If you are using less than 10% oats, you should not run into problems with your first runnings. The sparge will be longer than usual due to the oats. Anything over 10%, you will want to add at least a pound of rice hulls. The beta-glucans make the oatmeal a gummy consistency.

You can also impart a two-step mash with a 20 minute rest between 98°F and 113°F (36°C – 45°C). This will help with the beta-glucanase enzymes that break down the beta-glucans. After this, raise your temperature to a scarification temperature at around 153°F (67°C) and hold for 60 minutes.

After the 60 minutes are up, raise the mash temperature to 168°F (75°C) to stop enzyme activity. 

Oatmeal Stout the By the Numbers

  • Color Range: 22 – 40 SRM
  • Original Gravity: 1.045 – 1.065 OG
  • Final Gravity: 1.010 – 1.018 FG
  • IBU Range: 20 – 40
  • ABV Range: 4.2 – 5.9%

Martin Keen’s Oatmeal Stout Recipe

Grain

64%        7 lbs        Maris Otter

14%        1lb 8 oz   Flaked Oats  

  9%        1 lb          Pale Chocolate

  9%        1 lb          Crystal 45  

  4%        8 oz         Roasted Barley

 Hops

1.5 oz          Fuggles – Boil 60 min

  .5 oz           Fuggles – Boil 10 min

Yeast

1.0 pkg   Whitehead Ale Yeast Wyeast 1099

Directions

Mash at 152°F (66°C) for 60 mins

Boil for 60 mins 

Transcript: Oatmeal stout might sound like a drink best consumed with a spoon, but it’s actually a light, easy drinking stout suitable for sipping on a hot day, I’m going to attempt to brew one. Then carbonate the beer and perform a fully closed transfer of it without any assistance from my CO2 tank.

I’m Martin Keen taking the Homebrew challenge to brew 99 beers in 99 weeks. If I had to come up with one descriptor for a good oatmeal stout, that would be smooth. This is a beer, it should be roasty and grainy without any trace of coffee, but very easy drinking.

And we’re going to build a beer here that is an original gravity of 10 56, that will give us a 5.3% ABV. And this is an English stout. So English stout recipe rules apply here. We’re going to use a lot of English, grains, roasted body, that sort of thing.

So for the base malt, 64% of the crest is Maris Otter. Then it will probably come as no surprise that the next ingredient in an oatmeal stout is oats. I’m using flaked oats, and these will contribute to both the grainy taste of the beer, but also to that smooth mouth feel. So I’m going to use 14% flaked oats. In addition to that, I have 9% paler chocolate malt and 9% crystal 45, and then 4% roasted barley.

Mashing in at 152 Fahrenheit or 67 Celsius. All right, I’ve been putting this off, but it’s time to say goodbye to an old friend.

Fuggle hops for this beer, both the bittering hop and the flavor and aroma hop. So at the start of a boil, I’m going to add in enough fuggle hops to get to 25 IBU. So if you bring a five gallon batch, that will be one and a half ounces of fuggle hops, and then 10 minutes from the end going to add another charge of fuggle hops, uh, that will contribute about three IBU. And that in a five gallon batch is going to be a half ounce.

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I’ve really come to like these fermzilla’s specifically this one, the fermzilla’s all rounder because it allows me to perform a closed transfer from the fermenter into the keg without exposing the beer to any oxygen.

And I was chatting with my buddy Brian, over at short-circuited brewers about this. And he also has the same setup and he’s put together for me a cool little tutorial to illustrate exactly how to do it. So Brian, over to you.

Thanks Martin. If you want to preserve the flavor and integrity of your beer, one of the things you want to avoid is oxygen exposure. One of the effects of that is you can have your beer turnout tasting like cardboard or a darkens in color. And so what I’m going to show you today is the closed loop transfer, which means that I’m going to transfer from the fermzilla’s all rounder down into a keg and then fill the space that’s in the all-rounder with the CO2 that is in the keg. And what we’ll be using for the transfer is going to be the keg land five millimeter ID, Eva barrier hose, along with four duo type fittings and four MFL ball lock fittings to liquid and to gas to prepare for the transfer. I wanted to make sure that the oxygen was completely purged from the keg.

So I filled it with a mild solution of starsan and water, and I filled it all the way to the top until it was overflowing. You’ll have to do that with some of the foam coming out of the top. You can’t really see where the water level is until it gets to the top. So after I did that, I put the lid on the keg and then hooked up my CO2 tank and purged any Headspace with any oxygen and all that might’ve been in there. After that, I took off one of the fittings of the jumper hoses and actually used it to drain the keg. And I swapped hoses midway through to make sure that both of them were sanitized. I purged both of the transfer lines by hooking them up to the keg that was pressurized with CO2. And then re-installed the sanitized ball lock fittings.

All right. So what I’m gonna do is I’m gonna hook up the liquid side of the jumper hose to the liquid side of the all-rounder good and hook that up. And I’ve got the all-rounder pressurized with about 12 PSI and the keg is pressurized to about the same and you can kind of see that some of the liquid is already in there.

So I’m actually going to put this on the liquid outpost of the keg and snap that on. And as you see, there was a little bit of transfer there, but the pressure will equalize pretty quickly in both of the vessels. So what we’re going to want to do is we’re actually going to want to purge a little bit of the CO2 pressure in the keg, and that will actually start our transfer going. And then once we do that, once we know the transfer is started, I’m going to snap on the CO2 line fitting and then connect it to the, in on the all-rounder. Now what will happen is as the beer fills the keg, it will push out the CO2 and the CO2 will actually fill the space in the all-rounder.

Thanks, Brian. Now he has an extra tip for me to enable me to perform a closed transfer without any assistance from CO2, from this guy. And I’m going to show you how to do that, but we need to get some beer in here. First

Beer has come in at 10 52. I’m adding WYEast 1099. That’s whitbread Ale yeast to the beer. Okay. Let’s talk about this cool little tip for closed transfers. So Brian, back over to you.

Here’s what we’re going to do with an all-rounder. It is a pressurized fermentation vessel. So what we can do is we can actually put the gas line or gas fitting on our Eva barrier hose with a dual type fitting. And then on the other end, put the liquid ball lock. And then depending on whether you’re doing pressure fermentation, or if you’re doing just a regular standard fermentation, if you’re doing a pressurized fermentation, like I’ve done, you would want a spuding valve and you put that on the gas side of your keg. And then as your fermentation occurs, you’re going to be pushing CO2 through the line to the bottom of the dip tube. And that’s important because CO2 is actually heavier than oxygen.

So as your fermentation occurs, it’s going to push CO2 into the keg and then it’s going to fill from the bottom up, forcing out any oxygen. Now, if you’re not doing a pressure fermentation, just want to use this like, like that without doing a pressure fermentation or a spunding valve, you can just simply crack the pressure relief valve on the keg and let it fill up and basically use your keg as an air lock, back to you, Martin.

So I really like this suggestion and here’s what I’ve done. I have hooked up the gas out from the fermzilla’s to the liquid in on my keg. And then on my keg, I’ve added a spunding valve.

Now I’m not going to ferment this beer under pressure per se. So what I’ve done is I’ve set the spunding valve to five PSI, which means if we get above five PSI, the gas is just going to come out of here. So the beer is not going to be under any significant pressure during fermentation. That is until fermentation is nearly complete. And what I’m going to do then is I’m going to bump up this spending valve to 15 PSI. So we’ll get 15 PSI of pressure built in the fermentor and in the keg. And the advantage of that is it will force carbonate my beer. So that will save me doing it myself later with my CO2 tank.

Then when fermentation is complete, I should be left with a keg, full of CO2, ready for a close transfer at a fermenter full of already fizzy beer.

So it is now time to taste the oatmeal stout. No, no, no, no, no. Bye bye. See you on the next milk stout review. Okay.

Well Lauren, welcome to this with your lovely new haircut. Now the, uh, the process actually worked brilliantly, the whole transferring in kegs thing and it, it, it made itself fizzy. So I didn’t have to do any force carbonation. Uh, so let’s take a look at what you think of this oatmeal stout in terms of its appearance.

They’re always so dark. Yeah, Yeah, yeah. It’s a dark stout. So

Like yeah, really dark. Okay.So let’s see if we get anything on the nose smell wise. It does smell quite smooth. Um, I want us to say, are there some caramel under notes on this? Yeah, possibly that’s nice, smell smells like it’s going to be kind of sweet. That’s good. Okay. Okay.

So is this a beer you drink for breakfast?

Um, maybe I definitely have to say like, after all these dark beers we would do in, like I’m getting a taste for them and I’m actually like learning this one has. Yeah, it definitely, I’d say it’s a little bit like caramel.

With the sort of the flaked ingredients here. This should add to sort of quite a creamy mouthfeel, even though it’s not a nitro served beer. Tastes a bit like chocolate, dark chocolate. So I’m definitely getting a bit of the chocolate sort of characteristic as well. I would say a little bit more milk chocolate than dark chocolate for me.

We are sticking with Stouts next week with a stout that I don’t think either of us had ever tried.

I am the former President of my homebrew club, Plainfield Ale and Lager Enthusiasts (PALE) in the western suburbs of Chicago, IL. I brew on my BIAB system with my incredibly patient and understanding wife, adorable 9 year old daughter, and 12 year old brew dog.