Home > Beer Styles > Brewing an Oatmeal Stout
Mashing-in complete
Mashing-in complete

Brewing an Oatmeal Stout

Previously in this series of articles on How to brew different Styles of Beer? we covered Brewing an Irish Red Ale, this time the Beer Style comes from the ‘Dark British Beer’ category in the BJCP 2014 Guidelines and is the style of an Oatmeal Stout.

In the following sections we are going to examine different aspects of this style such as its background, the style guidelines, ingredients used, sample recipes, brewing process, and finally the outcome of brewing a batch of this beer.


Maris Otter & Rolled Oats
Maris Otter & Rolled Oats

An Oatmeal Stout originates from the late 19th century and is similar to a Sweet/Milk Stout but instead of using lactose the recipes include oatmeal in the malt bill. The oatmeal usually takes the form of rolled or flaked oats.

This style of beer was most popular in the first half of the 20th century and has had a resurgence in recent years due to the availability of exported versions and being adopted by the Craft Beer revolution in the USA.

Commercial examples of this style include Samuel Smith Oatmeal Stout, Young’s Oatmeal Stout, McAuslan Oatmeal Stout, Maclay’s Oat Malt
Stout, Broughton Kinmount Willie Oatmeal Stout, Anderson Valley Barney Flats Oatmeal Stout, Tröegs Oatmeal Stout, New Holland The Poet, Goose Island Oatmeal Stout, Wolaver’s Oatmeal Stout. Samuel Smith’s is widely available in 500ml bottles around the world.


In the BJCP 2008 Style Guidelines the Oatmeal Stout was grouped together with all other types of Stouts in the Stout category (see here), but now the category has been split with most of the Stout styles going into the Dark British Beer category and Dry Stout going into the Irish Beer category along with Irish Red Ale as follows:

BJCP 2014 BJCP 2008
Category 16: Dark British Beer 13: Stout
Styles 16A: Sweet Stout 13B: Sweet Stout
16B: Oatmeal Stout 13C: Oatmeal Stout
16C: Tropical Stout 13D: Foreign Extra Stout
16D: Foreign Export Stout 13D: Foreign Extra Stout

In the new guidelines the vital statistics of the Oatmeal Stout has only had one minor change and that is the raising of the lower range of the Starting Gravity by 3 points:

  • Original Gravity (OG) = 1.045 – 1.065
  • Final Gravity (FG) = 1.010 – 1.018
  • Alcohol By Volume (ABV) = 4.2 – 5.9%
  • Bitterness (IBUs) = 25 – 40
  • Color (SRM) = 22 – 40


Specialty grains
Specialty grains:
– Crystal 60L
– Chocolate Dark 6-row
– Roasted Barley
– Crystal 40L

According to the BJCP 2014 Guidelines the following are characteristic ingredients used in the brewing of an Oatmeal Stout:

  • Malts: Pale, caramel and dark roasted malts (often chocolate) and grains. Oatmeal (5-20%) used to enhance fullness of body and complexity of flavor.
  • Hops: Not specified but usually English varieties used primarily for bittering.
  • Yeast: An English Ale yeast.
  • Water: Not specified.
  • Additions: Can use brewing sugars or syrups.


Below are some sample recipes for 5 gallon batches of Oatmeal Stouts from leading authors in the homebrewing community together with some analysis on how they comply with the style guidelines:

– Barrel of Monkey’s Wheat-Oatmeal Nut Stout –

Mashing-in complete
Mashing-in complete

Source: The Homebrewer’s Companion
Author: Charlie Papazian

  • 5 Lbs Pale 2-row malt
  • 2 Lbs Wheat malt
  • 1 Lb Crystal/Caramel malt
  • 10 oz Quick Oatmeal
  • 8 oz Roasted Barley
  • 8 oz Roasted Black malt
  • 2.5 oz English Fuggles or Goldings hops (bittering)
  • 0.5 oz English Fuggles or Goldings hops (flavor)
  • 0.5 oz English Fuggles or Goldings hops (aroma)
  • Ale yeast


  • OG: 1.053 – 1.060
  • FG: 1.016 – 1.020
  • ABV: 4.3 – 5.8%
  • Bitterness: 56 IBUs
  • Color: > 50 SRM


  • Malts: the base and specialty malts in this recipe are mostly within style though the use of Wheat malt is not. The Wheat malt in conjunction with the use of Quick Oatmeal may lead to a stuck mash so it would be prudent to also add rice hulls to help avoid this. Note that the specific type of Crystal/Caramel malt is not specified.
  • Hops: these are traditional English varieties and the hopping regime is ‘old-school’ though the style guidelines only mention bittering with no flavoring or aroma additions. The resultant amount of IBUs are too high for the style guidelines.
  • Yeast: a yeast is not specified but some form of English Ale yeast would be the way to go.
  • Statistics: the Starting Gravity and alcohol content are in line with the style guidelines though the Finishing Gravity can be a little on the high side. The bitterness and color, however, are significantly higher.

– Lakeside Stout –

Wort pre-boil
Wort pre-boil

Source: Brewing Better Beer
Author: Gordon Strong

  • 12 Lbs Maris Otter malt
  • 1.5 Lbs Flaked oats
  • 1.0 Lb Crystal 80L
  • 4 oz Crystal 40L
  • 12 oz Chocolate malt
  • 8 oz Roasted Barley
  • 0.8 oz East Kent Goldings hops (60 min)
  • 0.6 oz East Kent Goldings hops (30 min)
  • London Ale III yeast (Wyeast 1318)


  • OG: 1.062
  • FG: 1.018
  • ABV: 5.8%
  • Bitterness: 25 IBUs
  • Color: not specified


  • Malts: the base and specialty malts in this recipe are completely within the style guidelines.
  • Hops: this is a traditional English variety that is used as two bittering additions with the second to help impart some degree of flavor as well.
  • Yeast: the Wyeast web site describes this as ‘originating from a traditional London brewery, this yeast has a wonderful malt and hop profile. It is a true top cropping strain with a fruity, very light and softly balanced palate. This strain will finish slightly sweet’.
  • Statistics: the Starting and Finishing Gravities, as well as the alcohol content, are all towards the top of the style ranges though the bitterness is at the bottom of the IBU range.

– Oatmeal Stout –

Overactive fermentation
Overactive fermentation

Source: Wisdom for Home Brewers
Author: Ted Bruning & Nigel Sadler

  • 9.25 Lbs Pale malt
  • 8.8 Rolled oats
  • 7 oz Crystal malt
  • 5.6 oz Chocolate malt
  • 2.5 oz Roasted Barley
  • 1.4 oz Challenger hops (60 min)
  • 0.5 oz Challenger hops (0 min)
  • 0.5 oz Golding hops (0 min)


  • OG: 1.049
  • FG: 1.014
  • ABV: 4.6%


  • Malts: the base malt in this recipe is not specified as a British variety but that would make most sense for authenticity purposes. The Crystal malt is also not specified so a combination of Crystal 40L and some 120L might help give a touch of caramel and some body plus maltiness though the Rolled oats will also contribute to both body and mouth-feel. For the remaining specialty malts the author has gone with both Chocolate and Roasted.
  • Hops: these are traditional English varieties.
  • Yeast: no yeast has been specified but some form of English Ale yeast would be appropriate.
  • Statistics: not all of the statistics are provided but the ones that are available are within style.


Steps in brewing process
Steps in brewing process

The recipe chosen for brewing this batch of Oatmeal Stout was the Lakeside Stout with the reason for this choice being a concern that the Barrel of Monkey’s Wheat-Oatmeal Nut Stout uses Wheat which is not to style and the use of breakfast cereal (Quick Oatmeal) seems an old approach given the availability of quality ingredients nowadays.

The last sample recipe did not appeal due to some vagueness over the ingredients e.g. which Lovibond of each specialty grain would be best to deliver the right finished beer. The Lakeside Stout provides plenty of specific guidance on which ingredients to use so looked a good choice to go with.

The recipe instructions specified that the dark grains should be added during vorlauf but given my system is BIAB (Brew In A Bag) and therefore constantly recirculates this is not feasible so under Gordon’s guidance I opted for adding them during the last 15 minutes of the mash.

An additional adjustment I had to make was substituting Crystal 60L for 80L as I only had the former and not the latter though I did adjust the quantity so that the same target color and gravity were within my recipe.

The 5 gallon batch of beer was brewed following these steps:

  • Charcoal filtering the borough water and leaving it to stand overnight in order to vent off the chlorine.
  • Measuring out and milling the grains, also measuring out the hops and irish moss.
  • Sterilizing the fermentation equipment.
  • Heating the strike water to 155 deg F before mashing-in (adding the grist to the hot water).
  • Mashing for 45 mins at 153 deg F so the starches convert into sugars (pH 6.2).
  • Stop recirculation and add dark (specialty) grains.
  • Continue mashing for a further 15 mins at 153 deg F.
  • Raising the temperature to 168 deg F to mash-out and stop enzymatic activity i.e. halt the conversion of starches to sugars.
  • Boiling for 30 mins to allow time for the hot break to clear and volume to reduce.
  • Continue boiling for 30 mins with bittering hop addition.
  • Add second bittering/flavoring hops and continue boiling for 15 mins.
  • Adding Irish Moss at 15 mins to help clear the beer.
  • A yeast starter was prepared comprising of 8 oz of DME (Dry Malt Extract) in two liters of water and placed in a flask on a stir plate together with one packet of yeast.
  • Yeast nutrient was added to the wort once it had been cooled.
  • Wort was aerated with Oxygen (60 secs) via a diffusing stone connected to an O2 tank with a regulator.
  • Yeast starter was decanted prior to pitching into the wort so that most of the spent wort did not go into the beer.
  • Primary fermentation was at 68 deg F for one week in a temperature controlled freezer.
  • The beer was racked off the trub (sediment) into the secondary fermenter and held at 68 deg F for two weeks.
  • Beer was force carbonated to 2.3 volumes of CO2 after cooling the beer to 36 deg F.


Brewing temperature profile
Brewing temperature profile

According to the style guidelines an Oatmeal Stout should have the following characteristics:

  • Appearance: Medium brown to black in color. Thick, creamy, persistent tan- to brown-colored head. Can be opaque (if not, it should be clear).
  • Aroma: Mild roasted grain aromas, generally with a coffee-like character. A light malty sweetness can suggest a coffee-and-cream impression. Fruitiness should be low to medium-high. Diacetyl medium-low to none. Hop aroma medium-low to none, earthy or floral. A light grainy-nutty oatmeal aroma is optional.
  • Flavor: Similar to the aroma, with a mild roasted coffee to coffee-and-cream flavor, and low to moderately-high fruitiness. Oats and dark roasted grains provide some flavor complexity; the oats can add a nutty, grainy or earthy flavor. Dark grains can combine with malt sweetness to give the impression of milk chocolate or coffee with cream. Medium hop bitterness with the balance toward malt. Medium-sweet to medium-dry finish. Diacetyl medium-low to none. Hop flavor medium-low to none, typically earthy or floral.
  • Mouth-feel: Medium-full to full body, with a smooth, silky, velvety, sometimes an almost oily slickness from the oatmeal. Creamy. Medium to medium-high carbonation.
  • Overall: A very dark, full-bodied, roasty, malty ale with a complementary oatmeal flavor. The sweetness, balance, and oatmeal impression can vary considerably.
Carboy of aerated wort
Carboy of aerated wort

A common factor with these sample recipes is the use of a Pale base malt with some degree of Crystal, Roasted and Chocolate specialty malts and Oatmeal as you would expect. The choice of hops are English varieties and in the main an English Ale yeast is specified.

How did my batch of Oatmeal Stout turn out?

The Original Gravity fell short by 10 points which was disappointing and the only reason I can imagine is that it did not fully convert even though I performed an Iodine test on the mash. The fermentation also fell a little short by 2 points but the resultant alcohol percentage, Original and Final Gravities all remained within style.

Here are the actual vital statistics:

  • OG: 1.052
  • FG: 1.018
  • ABV: 4.46%
  • Bitterness: 24.9 IBUs
  • Color: 27.9 SRM
Oatmeal Stout sample
Oatmeal Stout sample

The tasting notes are as follows:

Dark red in color with a thin tan head. A slight roasty aroma. Flavor begins with a bit of sweetness and is then followed by roastiness. Low carbonation with a thin body and slight metallic and cocoa after-taste.

Overall the head retention is not very good and whilst the flavor is pleasant the mouth-feel is a bit too thin. If I were to brew this recipe again I would mash for longer to ensure proper conversion and a higher Starting Gravity with the hope that this would also contribute to better head retention.

What’s Next?

In my next article in this series I will be examining Brewing a Belgian Dubbel which is in the ‘Trappist Ale’ category so please check back for that article to be published.

Brew-BossThis article is made possible by Brew-Boss, to find out more about Electric Brewing systems and configuration options offered by Brew-Boss please click on their logo to check them out.

Comments or questions? If you have any comments or questions on this article please do not hesitate to leave them below.

Leave a Reply

Your email address will not be published. Required fields are marked *