Oatmeal Stout

Equipment Required

• Brew kettle (5+ gallon)
• Fermenting bucket or carboy (6.5 gallon) with airlock
• Sanitizer (Star San or similar — sanitization is the #1 rule of brewing)
• Auto-siphon and tubing
• Hydrometer (for measuring gravity/alcohol)
• Thermometer
• Bottling bucket, bottles, caps, and capper (or a kegging system)
• Large stirring spoon

Ingredients

• 6 lbs dark liquid malt extract (LME)
• 1 lb rolled oats (flaked, not instant)
• 0.75 lb roasted barley (500°L)
• 0.5 lb chocolate malt (350°L)
• 0.25 lb black patent malt (500°L)
• 0.5 lb Crystal 80L malt
• 1 oz East Kent Goldings hops (60-minute bittering)
• 0.5 oz Fuggle hops (15-minute flavor)
• 1 packet Safale S-04 English ale yeast
• 5 oz priming sugar (for bottling)
• 5 gallons filtered water

Method

1. Prepare the partial mash. Combine the rolled oats, roasted barley, chocolate malt, black patent malt, and Crystal 80L in a muslin bag. Heat 3 gallons of water to 155°F and steep the grain bag for 30 minutes, maintaining 150–160°F. The oats contribute beta-glucans — long-chain sugars that create the silky, full mouthfeel that defines this style. The roasted grains provide color (SRM 30–40) and the chocolate and coffee flavors.

2. Remove grains and add extract. Lift the grain bag and let it drip for a minute. Remove the pot from heat and stir in the dark LME until fully dissolved. Return to heat and bring to a boil.

3. Boil with hops. Add 1 oz East Kent Goldings at 60 minutes — stouts are malt-forward, so you want restrained bitterness (target 25–30 IBUs). Add 0.5 oz Fuggle at 15 minutes for earthy, herbal flavor that complements the roast character. English hop varieties are traditional for this style.

4. Cool and transfer. Cool the wort to 65°F using an ice bath or wort chiller. Transfer to a sanitized fermenter and top up to 5 gallons. Aerate by shaking for 2 minutes. Target OG: 1.048–1.054.

5. Pitch yeast and ferment. Sprinkle S-04 on top of the wort. Ferment at 64–68°F for 10–14 days. S-04 is an English ale strain that produces mild fruity esters and flocculates well, leaving a relatively clear beer despite the dark color. Check FG — target 1.012–1.016 for a medium-bodied stout.

6. Bottle. Dissolve 5 oz priming sugar in 2 cups boiling water, cool, and gently stir into the beer. Fill bottles, cap, and condition at room temperature for 2–3 weeks. Stouts benefit from extra conditioning time — the roast flavors mellow and the oat smoothness becomes more pronounced after 4–6 weeks.

What You're Practicing

This recipe teaches you how specialty grains define a beer's character beyond what extract alone can achieve. Roasted barley, chocolate malt, and black patent each contribute different Maillard reaction products — the same chemistry that makes toast taste different from bread. The oats introduce you to adjunct brewing — using non-barley grains to modify body and texture. Beta-glucans from oats increase viscosity, which your palate perceives as creaminess. You are also learning about Lovibond ratings (°L), which measure grain color and predict beer color in SRM. The restrained hop schedule demonstrates that balance in a stout comes from malt-hop interplay, not hop dominance. Fermentation temperature control with S-04 teaches you how yeast strain selection affects flavor — this strain produces fewer esters than Belgian strains but more than a clean American strain like US-05. See Fermentation Science for more on how temperature shapes yeast behavior.