Monday, April 16, 2012

Adding Oats to the Boil - Coffee Stout

For many brewers the basic procedure for every recipe is the same: grind the grain, single infusion mash, sparge (or not), boil the runnings with hops, chill, pitch, ferment, package. Sure there are subtle variations to temperatures and times, but essentially the same process can yield either an Imperial Stout or a Pilsner just by altering the malts/grains/hops/yeast. I still enjoy my “standard” brew days, but after brewing nearly 200 batches over the last seven years, it is more fun when I get to try a new technique.

Half a pound of flaked oats going into the boil.
One of my goals is to brew a moderate gravity stout that drinks with the thick body of an Imperial Stout. Rather than simply mashing really hot, or loading up on crystal malt, I was alerted to another option, adding quick oats to the wort near the end of the boil. I have been told that The Alchemist has used this method to add a thick body to some of their beers without increasing sweetness. Oats contain beta glucans (a type of soluble fiber) which are responsible for the smooth viscosity they add to oatmeal stouts.

I know, one of the first things that new brewers are taught is to avoid steeping grains that contain starch. The common thinking goes that adding starch to a beer is just asking for trouble since it is unfermentable by brewer’s yeast, making it an invitation to spoilage microbes. The problem with this line of thinking is that so are dextrins, which add body to beers. In fact, dextrins are a much easier to ferment source of carbon for common spoilage microbes like Brettanomyces and Lactobacillus, which usually lack the enzymes required to tackle (hydrolyze) longer chain carbohydrates like starch. Since flaked oats do not contain a husk, there is also no major concern about tannins (as there would be adding malted barley to the boil).

Oats strained out after the boil.
After sprinkling the half pound of quick oats into the boiling wort, I let them sit in there through chilling. I strained them out of the cool wort, along with the hops, when I transferred to the fermentor. Rather than the thick gloppy mess I expected, each flake had contracted into a neat little pellet. Hopefully this means that the starches and beta glucans that usually provide the thick texture in a bowl of oatmeal are suspended in the wort. Fermentation exhibited a dense krausen, but the Fuller’s strain I pitched is known for that as well. I was happy that I used an eight gallon wine bucket for primary fermentation, rather than one of the six gallon Better Bottles I have used in the past. It is nice not to worry about attaching a blow-off tube.

For the rest of the recipe I drew inspiration from the Munich Porter that Nate and I brewed a couple years ago. It relied on dark grains that were lighter than the usually 500+ L versions of Roasted Barley and Black Patent. Our porter was good, but the roast character was too mellow/smooth with only a half pound each of Briess Roasted Barley and Chocolate malt. So for this batch I doubled the roasted barley and edged up the chocolate malt. Hopefully the higher amounts will produce a smooth cocoa and coffee roast, without a burnt/acrid edge. If the roast still isn't potent enough, I'll have to go to a combination of lighter and darker roasted grains to get the effect I am looking for.

A starter of WLP002 on my stir plate.
I will be steeping a few ounces of roasted coffee beans in the beer for about 24 hours prior to kegging. This is a technique I’ve used a couple times in the past (like the Coffee, Chocolate, Maple, Imperial Oatmeal Stout) because it delivers a nice aromatic character without getting bitter or harsh in the same way that hot-side additions sometimes do. I also find that its flavor is more persistent than coffee additions cold steeped in water, which start to fade after just a few weeks.

After the India Amber Ale, this is the second test batch I’ve brewed for Modern Times. Although I overshot the gravity, I’d like to bring it down closer to 5% ABV mark in future iterations.

Black House #1
Recipe Specifics
--------------------
Batch Size (Gal): 5.25
Total Grain (Lbs): 11.75
Anticipated OG: 1.059
Anticipated SRM: 39.3
Anticipated IBU: 32.5
Brewhouse Efficiency: 75 %
Wort Boil Time: 75 Minutes

Grain
-------
76.6% - 9.00 lbs. Maris Otter
8.5% - 1.00 lbs. Roasted Barley (~300 L)
5.3% - 0.63 lbs. Chocolate Malt
4.3% - 0.50 lbs. Quick Oats
3.2% - 0.38 lbs. Crystal 90L
2.1% - 0.25 lbs. CaraMunich Malt

Hops
------
1.25 oz. Hallertau Tradition (Pellet, 6.00% AA) @ 70 min.
0.75 oz. Hallertau Tradition (Pellet, 6.00% AA) @ 5 min.

Extras
--------
0.50 Whirlfloc @ 15 min.
0.25 tsp Yeast Nutrient @ 15 min.
2.00 oz Coffee Beans for 1 day

Yeast
-------
White Labs WLP002 English Ale

Water Profile
---------------
Profile: Washington DC

Mash Schedule
-----------------
Sacch Rest - 75 min @ 153 F

Notes
-------
Brewed 4/8/12 with Elena

Cut mash water with 1 gallon of distilled.

Fly sparged. Collected 7 gallons of wort.

Added the Quaker quick oats for the last 10 minutes of the boil. Chilled to 66, strained out the oats/hops, pitched a .75 l starter of yeast, and shook to aerate. Overshot the gravity slightly.

"I've heard good things about adding quick oats for the last 10 minutes of the boil" - Re: Alchemist

Fermenting well by 18 hours. At ~62 F ambient for the first week.

4/14/12 Fermentation appears finished.

4/15/12 Temperature warming close to 70 F, so I roused the yeast by twisting the bucket back and forth for 30 seconds to ensure it eliminates any remaining diacetyl.

4/22/12 Only got down to 1.019, guess that's the oats. Added 2 oz of coarsely crushed Mocha Java Blend coffee beans in a weighted stocking. Kegged 24 hours later.

5/10/12 Reasonably happy with the results of this first try, but the oats didn't add the creaminess I was looking for. I'll be moving them to the mash and boosting them in the next batch.

6/9/12 Brewed a second iteration of this recipe.

21 comments:

Glen said...

I've always had trouble getting that big mouthfeel from oats that everyone talks about (or my expectations are too high). This is a great idea, I'll be watching closely for your results. Cheers!

Bassman said...

Could the higher OG be due to the added starch from the oats i.e. the amount of fermentable sugars are the same but the wort is more dense. However, this is on the assumption that you are measuring the OG via hydrometer and not a refrac!

The Mad Fermentationist (Mike) said...

If anything I'd be suspicious that adding the oats like this would hurt efficiency, since rather than being sparged they are sucking up dense wort near the end of the boil. I'll be interested to see what sort of attenuation results. I think the higher than expected efficiency was due to me finally getting a set of feeler gauges and clamping down the gap on my mill to .95 mm.

Aaron Burgener said...

Interesting, I look forward to the results of this one! Did straining the oats give you any trouble, or was it pretty much just like hops? I use a large fine mesh bag for my boil hops - I was thinking if I tried this, I'd just pour my oats into the same bag to strain... Thanks!

Hopwise said...

Do you use whole or ground coffee beans? I wouldn't think that whole beans would provide a lot of flavor.

The Mad Fermentationist (Mike) said...

No issues straining the oats out of the wort, although there were a lot more of them than you’d usually have hops.

I’ve used both whole coffee beans and coarse ground. The lower surface area of whole beans means the beers extracts their flavor at a slower rate, it probably takes three to four times longer to get the same flavor. However, whole beans are much easier to deal with since they do not need to be put into a fine mesh bag.

Jeff Holt said...

Interesting. I'll be watching for the results.

Jeffrey Crane said...

Pending your results, don't you think this is a great way to improve the mouthfeel of long aged sour beers?

The Mad Fermentationist (Mike) said...

It would depend on the microbes, I believe some strains of Brett and Pedio are be able to tear through the long chains of glucose. It might be an easy work around for a turbid mash, or given less aggressive microbes certainly could help body.

Andrew said...

Chad Yakobson (Crooked Stave) just did a Brewing Newtwork sunday session on this. He dicussed that proteins are the way to get better mouthfeel in the brett beers. So things like wheat, rye, oats, etc. should be effective in keeping something around in the beer (if you don't get glycerol from your microorganism during fermentation). The whole interview was *very* good.

Jesse said...

I know this is a dark beer, but did the oats add any cloudiness from starches, beta glucans, etc? If you used this method in a pale beer do you think it would be make it noticeably turbid?

Second on the Crooked Stave interview on the BN.

The Mad Fermentationist (Mike) said...

I haven't listened to the interview, but was Chad talking about sour beers, or 100% Brett beers? Lack of glycerol production is the issue with 100% Brett ferments. Pedio tends to be able to tackle large molecules than Brett, it can hydrolyze starches. I’ll listen to it when I get a chance.

I'll take a good look at the clarity when the beer is fermented, but I'm sure this technique would badly cloud a pale beer. I even got a decent amount of turbidity just adding a healthy percentage of oats to the mash for a pale ale.

Don said...

Do you think a large fine mesh bag would be a subsitute for straining? I can see myself making a mess in my kitchen trying to strain the oats.

Andrew said...

Transcription from the Session:

I get a lot of emails from people, should I mash higher to leave more fermentables, and that is not the place to take care of the mouthfeel issue with brett. It is an actual flaw in the yeast. Sacc produces glycerol, and that is mouthfeel in beer. We tend to think mouthfeel is dextrins; its actually the glycerol. Brett doesn't have these metabolic pathways (to produce glycerol). Mash higher just means a longer time to FG. I (Chad) use proteins, they stay around in the beer. Thats the reason people you rye, people use oats. Those proteins are not going to be fermented out like the sugars.

The Mad Fermentationist (Mike) said...

Putting the oats in a mesh bag would be fine as long as it was big enough to let them swell. You might also want to add them a bit earlier just to make sure they give up their oaty goodness.

Chad is talking about 100% Brett beers, but if the mouthfeel is coming from proteins that should work fine for sour beers. In this case though, I’m not sure what effect the long chains of oat proteins will have since they have not been shortened by malting or mashing.

Anonymous said...

Would flaked barley produce the same effect as flaked oats?

The Mad Fermentationist (Mike) said...

flaked barley or flaked rye would have a similar sort of effect.

Just pulled a sample, gravity is still 1.019, but it doesn't taste that sweet. Body is thick, but not crazy. Looks a bit hazy, but nothing off-putting. Might just be the power of suggestion, but it does taste oat-ier than I'd expect for 1/2 lb.

Nateo said...

Do you think this technique would work with barley? I imagine the pH during the boil would be low enough you wouldn't get astringency even if you used barley. Decoction mashing does extract some tannins, but in a stout they might provide some nice structure.

The Mad Fermentationist (Mike) said...

I believe flaked barley is dehusked, so I don't think it would be an issue to boil it. Barley is lower in beta-glucans and protein, so while it would work, it wouldn't have as big of an effect/advantage.

Anonymous said...

I added 4 oz of flaked barley to the boil for a dry Irish Stout I brewed last weekend. My previous batch felt too thin. I'm hoping this does the trick.

spencer said...

I've been home-brewing awhile and being a 3floyds fan I absolutely need big body unless its a tinkerbell session beer. I've been using almost a single decoction with oats, base and sometimes specialty malts every brew with great results

Related Posts with Thumbnails