I am a big fan of using small amounts of flaked adjuncts like flaked wheat and flaked barley in my recipes to add some extra mouthfeel and boost head retention. Since St. Patrick’s Day is approaching I have been thinking about stouts and I have been itching to try my hand at making an oatmeal stout, which makes ample use of flaked oats for its signature creamy texture.
If you have never used oats in a recipe before, they lend a smooth, silky mouthfeel and a luscious creaminess that is hard to beat. Oats are relatively neutral in flavor (slightly oaty, naturally), but it is possible to bump the character up a notch by toasting them in the oven; toasting the oats will add a nice amount of nutty/biscuity character reminiscent of an oatmeal cookie. Oat toasting is a great technique for any style that you want a full, creamy mouthfeel and nutty/biscuity character, stouts and nut brown ales come to mind.
The challenge I discovered, however, was that when I was researching oat toasting technique there was sparse advice for the process beyond “cook in oven at 300ºF until toasted.” Thus, I decided to create this guide to toasting oats in hopes others would not share the same frustration I had as I worked out the proper technique.
Supplies
- Oats for toasting. I recommend using brewer’s flaked oats or instant oats (they are mostly the same thing), as the starches have been pre-gelatinized and do not require a cereal mash.
- Half-sheet baking pan. You can use whatever pan you have, but you don’t want the oats to sit too thick in the pan.
- Parchment paper (optional). I like parchment paper because it makes cleanup a snap, I can use it to funnel the oats back into a container, and I find it makes the oats less likely to scorch.
Instructions
Note: there are scattered reports of toasted oats giving off an astringent character for a few days after toasting. Some folks claim it lasts for weeks, some folks claim to have no problem immediately dumping their toasted oats directly from the oven into the mash; I typically toast my oats three or four days ahead of using them and have had no problems. If you are able to plan that far ahead, toast your oats a week or so before and keep them in a paper bag while they off-gas any harsh character.

The middle of the oven typically has the most even heat.
1) Adjust oven rack to middle of the oven and pre-heat to 300ºF.

Spread the oats out on a parchment lined baking sheet.
2) If you are using parchment paper, spread a sheet out over the half-sheet baking pan (or whatever pan you are using). Spread the oats over the baking sheet and give the pan a gentle shake to ensure they are evenly distributed. Try to keep the oats no more than about a half an inch deep.

Into the oven you go!
3) Place the oats in the oven and set a timer for 15 minutes. After the 15 minutes are up take the oats out, mix them up a bit, give them another gentle shake to even them out, and place them back in the oven. Repeat this 15 minute process until the oats have darkened to a golden color and give off a nutty oatmeal cookie aroma.
Ovens can vary quite a bit so it is important you check your oats and mix them up frequently. My oven took 1 hour to get the character I was looking for, but some folks claim it takes them anywhere from 30 minutes to 1 hour and 30 minutes.
For those wondering, “how golden is golden?” take a look at the before and after pics below. The color shifted from a pale white to an even golden character without any dark or burnt edges. The aroma during this time went from doughy-oat to oatmeal to nutty to Grape-Nuts to oatmeal cookie nutty. The smell can get intense but it should never smell burnt.
- Before
- After
4) Finally, as soon as your oats are just at the character you are looking for it is vital that you take them off the hot pan and spread them out somewhere to cool off. I just spread another sheet of parchment paper down on my counter and spread the oats out to let the heat dissipate. Otherwise, the oats will continue to cook in the pan and may develop harsh over-done character. As Alton Brown likes to say, “if it is done in the pan, it will be over-done on the plate.”
You should now have a batch of delightfully aromatic golden oats for your beer. Dump them into a paper bag and let them mellow out for a few days. On brew day just toss them in with the rest of your mash!
Update 2015/03/20: My buddy Olan over at Homebrew Dad just made a video guide on toasting oats you might also be interested in. The full article is over on his site, but here is the video.
Good stuff here, Derek! I’m one of those who definitely experience some odd flavors in freshly toasted oats, which dwindles after about a week. I used some fresh toasted in a Mild once and hated the character; I used the rest of that same batch in another lighter ale a month later and the oat character was much better.
I am looking for an explaination as why the most recent batch of my trusty oatmeal stout has an odd astringent and harsh flavour. This was my first attempt at toasting my oats. I directly chucked it ito the mash from the baking tray. I will not do that again. Thanks for the very useful post.
Yeah, def need some time to let the oats mellow post-toasting. Better luck next time!
What about putting the toasted oats in the refridgerator if you want to use them the next day?
My understanding is that it’s more of an off-gassing situation than anything related to temperature. That said, it’s not going to taste gross if you use it the next day, maybe just a little edgier.
Great article thanks for sharing your process! I just toasted some oats last night in prep for an upcoming brew, they taste kind of like popcorn to me right now wondering if you had any comment on that or similar experience? Maybe this will fade before brew day? Or not make it into the beer? Maybe this means I did not toast for long enough or too long? Any comments appreciated!
They should mellow out a bit, part of the reason why you want to let them rest in a bag for a bit before using. IMO, the toasting should be more nutty than “popcorny” but the flavors aren’t really that far off from each other.
cool, thanks for the reply. its been a couple days, they are mellowing indeed. will see how they are by brew day. thanks again, cheers!