Oatmeal Stout: Tips from the Pros

While a glass of oatmeal stout may or may not lower your cholesterol, it’s still pretty tasty. That’s because oatmeal brings a silky texture and vanilla-esque oat flavors to the party. In this issue, we found three brewers with advice for adding some oats to your next breakfast beer.

Justin Hamilton, Head Brewer, Chama River Brewing Co., Albuquerque, New Mexico. Justin started his career delivering kegs for the Blue Corn Café and Brewery in Santa Fe and worked his way up. He is currently enrolled at the American Brewers Guild and plans to graduate this summer.

The main reason we use oatmeal in our stout is that it can bring a smooth creamy finish to the mouthfeel, creates a nice viscosity and imparts other oat-y flavors.

We use Simpsons Golden Naked Oats, which are huskless and malted for a few different reasons. The most important of course is that they easily pass through our grain mill. In the past we used flaked oats, but they didn’t work so well. Plus, because of the way we mash in, the flaked oats affected our liquor-to mash ratio. I like that they impart a subtle nutty flavor and aroma.

In our oatmeal stout, I prefer to use them at about 3 to 5% of the grist. This gives me what I want from the oats without causing any lautering issues. A brewer can always control those qualities by adding more or less to the grist.

One of the issues brewers can run into when working with oats is that they have a large beta-glucan content. Too much oats in the grist can lead to difficulty with wort separation, so start small and work your way up.

If you’re already successfully brewing with oats, definitely experiment because that’s the fun part about brewing. I’ve seen some stouts with up to 20% oats in their grain bill, and you can definitely work your way up if you’re comfortable with the lautering issues that can come up. However, I would also be careful that you’re not adding too much. I wouldn’t try more than 25% — that’s going to be a lot of oats. Don’t overdo it.

John Haggerty, Brewmaster, New Holland Brewing Co., Holland, Michigan. John is a 2002 graduate of the Versuchs- und Lehranstalt für Brauerei (VLB) in Berlin, Germany where he received his brewmaster’s diploma.

We primarily use rolled oats at New Holland as opposed to malted oats. By using a non-malted grain you’re going to get a much longer protein chain, which will result in extra head retention and a creaminess that you wouldn’t get from a standard malted grain. They also have an oat-y flavor.

One of the things you have to be careful about when you use rolled oats is that they can create an oiliness in the beer that can be counterproductive.

We use oats at about 5 to 6% of the grist and then also augment it with some flaked barley. We like to use the barley to add a little more mouthfeel to the beer without going overboard in the oat flavor.

I don’t know that there’s any real precautions to take when using oats, but if you’re making an oatmeal stout you will have a bigger mash. In the case of rolled oats, you don’t want to and don’t need to mill it. Throw it right in the mash tun and it will keep the mash bed open.

If you’re making a stout with oats watch the pH. Dark malts tend to really acidify the mash pH, and when that happens you start to support roasty and bitter flavors. You want those flavors in the stout, but part of the reason for making an oatmeal stout is to bring up the creamy, vanilla qualities, so you’re going to want a higher pH of around 5.5 to 5.6.

Brewing with oats is just like everything else in brewing — you have to play with it and find your own sense of balance, flavor intensity, head formation and head retention. As you experiment, find ways to push and pull those different factors.

Damian McConn, Production and Project Brewer, Summit Brewing Company, Saint Paul, Minnesota. Born and Raised in Kildare, Ireland, Damian graduated from Heriot Watt University in Edinburgh, Scotland, with an Honours Bachelor’s Degree in Brewing and Distilling Science.

Oats are traditionally utilized in brewing for their impact on flavor and mouthfeel. In general they help to increase body, and add a soft, slightly silky smoothness to the overall profile of a beer. These attributes may help to temper the flavor contribution of other ingredients to the beer, such as the astringency provided by roast malts or high hopping rates.

The two main forms of oats used at Summit are golden oats, which are malted, and flaked oats, which are passed through heated rollers after an increase in moisture content. Malted oats have a unique nutty flavor in addition to their mouthfeel-enhancing qualities. Flaked oats are added directly to the mash tun.

Typical amounts in the grist range from 5 to 15%, although 8 to 10% is about standard in UK-style beers, a little less in Belgian beers. This is a sufficient level at which the benefits of the oats become obvious, but low enough to prevent brewhouse processing issues.

Oats contain very high levels of crude fiber, beta glucan and lipids (they were originally often used as feed for draught horses in Scotland). A thorough beta-glucanase rest during mashing (typically around 113 °F/45 °C) is highly recommended, as is the use of well-modified malts and possibly malt containing higher levels of beta glucanase than normal. Higher viscosities during lautering, and possible gum formation in the mash can impede run-off. This problem may contribute to decreased filtration through-put if the beer is filtered. Additional husk material in the form of rice hulls may help increase run-off rates.

Lipid oxidation, in both the raw material itself and the final beer may reduce shelf life and stability. Always use the freshest raw materials available and discard beers containing oats at the first signs of lipid oxidation (the beer may have a rancid-butter off-flavor and aroma). Lipids can also have a detrimental effect on foam retention; this can be offset by adding a small amount of torrified wheat to the grist.

Finely-ground oats can give a cement-like consistency to mashes, so milling-gaps should be adjusted to compensate if a malted product is used. Oats also contain lower extract and higher protein levels than standard UK 2-row pale malts, so consideration of these differences should be made during recipe calculations.


Issue: May-June 2010