Oatmeal Stout: The Proper Recipe

As you’ll know if you’re a regular follower of this blog, I recently designed an oatmeal stout recipe using the BJCP style guide. I wanted to see where pure numerical analysis of ingredients would get me.

While the beer came out fine, there was plenty of room for improvement. Here’s my updated recipe, which works much better.

oatmeal stout recipe beer

Although the previous brew turned out OK, it fell short in terms of what I expect from a stout.

For a start, it wasn’t really a stout.

oatmeal stout that came out like a porter

The beer looked and tasted like a porter. A couple of bottles even came out like a passable bitter (see photo).

I’m not sure how this happened. I’ve rechecked the recipe and the beer should have been much darker.

However, it’s not just the colour that I think could be improved.

With a fairly malty aroma, rather than the toasty roasty flavours that are more typical of stouts, it tasted good but not in the way I’d hoped.

The oats worked as planned and gave the beer a decent body, but there was not really any discernible oat flavour.

These issues were my starting point for honing in on a more pleasing recipe.

The Revised Oatmeal Stout Recipe

The changes I’ve made are all to the grain bill:

  • Increase crystal 120L and black malt
  • Toast oats and increase quantity
  • Add chocolate malt for more roastiness
  • reduce pale ale base malt and Munich malt to make room for these increases

This table of ingredients by percentage shows this more clearly:

Fermentable% Original% New Recipe
Pale Ale Malt6053
Munich Malt2018
Crystal 120L1011
Black Patent56

Here’s the resulting recipe:

Recipe Volume
10 litres

Pale Ale: 1.7 kg
Munich: 0.6kg
Crystal 120L: 0.35kg
Black Patent: 0.2kg
Oats: 0.2kg (toasted for 15mins @ 150°C)

Mash Time
90 mins

Mash Target Temperature

Fuggles (4.3%): 16g for 60 mins
Kent Goldings (4.5%): 25g for 20 mins
(34 IBUs)

Danstar Windsor Dry Yeast

Assumes 60% efficiency

Brew Notes

I largely followed my typical brew in a bag routine. However, I introduced a new rinsing stage to see if I could increase my efficiency.

Instead of starting with the full volume of water (1.5 times my target batch size, in this case 15 litres) I mashed with 12 litres. The other 3 litres I introduced later to sparge (rinse).

oatmeal stout grain

The mash itself was straightforward – straight away the smell was promising.

oatmeal stout recipe mash

I could see the liquid darkening in the pot. Getting a proper black stout seemed more likely this time.

oatmeal stout recipe brew bag mash

After 90 minutes I removed the bag with the grains and installed it in the fermenter. I’d already put an upturned bowl inside to form a false bottom and encourage draining.

oatmeal stout recipe sparge

Having put the wort in the brew pot to boil, I heated the remaining water to 78°C. This higher temperature encourages sugars left in the grain to dissolve and flow out of the bag.

oatmeal stout recipe sparge water

I divided the sparge water into two batches of 1.5 litres, letting the first fully drain before adding the other.

oatmeal stout recipe sparge

A fair bit of stirring was needed to get the wort out. Overall each sparge took about half an hour.

Because I did this while the main wort was heating, brew day wasn’t any longer as a result.

oatmeal stout recipe drain

After draining the two batches of sparge water I carried on with the brew as normal.

I got an original gravity of 1.060, higher than the 1.054 estimated on Hopville.

This rinsing method seems to have potential and I’ll definitely explore it more.

How to Toast Oats

To bring this to a close I’m going to quickly show you how to toast the oats.

toasting oats before

First spread them on a baking sheet.

Put it in the oven for 10 to 15 minutes at 150C. Be careful because the change from nothing happening to burnt is very quick.

Just leave them long enough until they start to smell homely – follow your nose.

toasting oats for an oatmeal stout

Take them from the oven and leave to cool.

toasting oats after

Add to the mash with the rest of the grain.

Tasting After Two Months

This beer is much more the sort of thing I was looking for the first time.

It has a very roast character, almost but not quite at the point of tasting burnt. If you’re of a sensitive disposition reduce the black and chocolate malts.

I also wish I’d used slightly less hops for bittering.

It’s still not a perfect recipe but it’s close enough for now. I’m going to leave stouts for a while and focus on something else.

Update: Tasting After After Six Months

Six months after brewing the stout had improved a lot.

The smell from the glass is mainly of hops, with a faint reminder of coffee.

The colour is fantastic, really black, and the head is the colour of tobacco stained walls.

To taste the beer is a little bitter (do I mean astringent?), which I assume is due to the chocolate and black malts.

There’s still a lot of bitterness from the hops, but that is more pleasant now, just about right. Hop aroma is more or less absent, but that was expected.

The beer’s a little too oily so I’d reduce the amount of oats if brewing again. It’s greasy rather than full bodied.

Overall there’s too much malt bitterness. I suspect the chocolate malt is the culprit and would consider omitting it from future batches.

Despite this, the overall malt taste is rich and flavoursome. It’s a good beer, but the oily texture and bitter aftertaste is heavy on the stomach and means you can’t drink much of it.

Easy on the dark malts and oats!

Next Up

I was planning to move onto a mild or pale ale, but having just read about the Beersay Saisonathon I may well change my mind.

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  1. This is really helpful. I’d like to try a stout this winter, so your notes will certainly come in handy. Great job troubleshooting this!

    • John

      Thanks Bryan!

      Stouts are fun to brew. The trick seems to be getting enough roasty malt flavour to be tasty, without passing the line into acrid and bitter.

      Let me know how yours turns out.

  2. Fabiano

    Hi John.
    I’m a new home brewer from Brazil. My fifth batch will be brewed tomorrow and is a oatmeal stout. Your website has been very helpful.

    About your second try on the oatmeal stout, did you put the dark malts since the beginning of the mash or in the last 30 minutes as the previous attempt?

    Cheers and good beers!

    • John

      Hi Fabiano,

      Thanks for stopping by.

      I put them in towards the end again. I’ve not done a side by side test, but having tasted black malt “tea” I’m always a bit weary of letting dark malts sit too long in the mash. They can really be unpleasantly bitter.

      If you do decide to add them later, just make sure they’re properly soaked.

      Good luck with your brew!

  3. Bob

    I recently brewed a stout and left out the patent and added more chocolate. It came out really smooth and tasty.

  4. Mike

    What I’ve tried doing over the last few stout batches was to steep the chocolate, carapils, roasted barley I use, 150* for 30 minutes. I drain, the heat to 170* and use as sparge water. The bitterness I used to get from mashing those has been greatly reduced. While my SG is down slightly on paper, It appears that my efficiency is up from the mash.

    • John

      Thanks for sharing the tips. I’ve had good results from steeping before, as well.