August 13, 2016: White Stout

This recipe was adapted from Experimental Homebrewing. This recipe will require us to expand our techniques in making a cacao tincture and adding lactose at packaging. Ingredients marked with a * were substitutions from the published recipe.

Grain bill:

• All supplies were purchased at Hops and Berries in Fort Collins, CO. Grain suppliers varied.
• 14 lbs Maris Otter
• 0.5 lb Crystal 40L
• 1 lb Flaked Oats
• 1 lb Flaked Barley

Hops (Pellet):

• 1.25 oz Target (UK) 11.1% alpha acids*
• 0.75 oz Crystal 4.8% alpha acids

Yeast:

• Wyeast 1318 London Ale III (#0829188, mfg 7/6/2016)

Specialty Ingredients:

• Defatted cacao extract (4 oz raw cacao nibs soaked in 6 oz Kirkland vodka for 24 hours, strained, placed in freezer to solidify fat for removal)
• Cold brewed coffee extract (1 c. ground coffee soaked in 3 c. water overnight, strained)
• 0.75 lb lactose dissolved in 3 c. boiling water.

Stats:

• Starting gravity: 1.062
• Brewhouse efficiency: 66%
• Final gravity: 1.016
• Approximate %ABV: 5.9%
• Approximate IBUs: 67.7 (Rager)/60.9 (Tinseth)/33.2 (Garetz)/69.2 (Daniels) as determined using the Hopsteiner, ProBrewer.com, and Homebrewing.com IBU calculators.

Procedure:

Yeast was propagated in 1 L of media (0.5 c DME in 1L/~1qt water, boiled) in a 2L flask with stir bar that had been sanitized with boiling water. Media was inoculated from Wyeast Smack Pack. Propagation culture was grown at room temperature with stirring for 15 hours and was pitched directly into the cooled, oxygenated wort.

Strike temperature was 75.5 degrees Celsius. A ~2:1 water to grist ratio was achieved with 12 liters of water. Mash in temperature was 67.7 degrees Celsius, which was the desired target. Mash out was conducted at 77 degrees Celsius. Sparging was a combination fly/batch and was conducted at 75 degree Celsius until the volume of sweet wort in the boil kettle was approximately 9 gallons. Hydrometer reading of the last wort remaining in the mash tun was 4.0 Brix.

Sweet wort was brought to a vigorous boil and boiled for 90 minutes. All hop addition times are listed as time remaining in the boil. Target pellets – 60 minutes; Crystal pellets, and 1/2 tablet Whirlfloc – 10 minutes. After whirlpooling and allowing the trub to settle, the hopped wort was cooled to 20 degrees Celsius with a counter-flow plate chiller with a recirculating ice/water slurry. The hopped wort was oxygenated via an oxygen tank for 60 seconds. The yeast propagation culture (~800 mL) was pitched into the Speidel fermenter. The fermenter was placed in an incubator that was set to a maximum temperature of 20 degrees Celsius.

Primary fermentation was approaching completion at approximately 100.5 hours. Acetaldehyde was detected around 64 hours and was less noticeable at 100.5 hours. Green was transferred to secondary fermenter and was kept at 70 degrees Celsius for approximately 48 hours. The fermenter was then chilled to -2 degrees Celsius which will help precipitate proteins and any remaining yeast cells. The cold incubation proceeded for two weeks since we were traveling for vacation.

The beer was then transferred to a 1/3 keg. Also added to the keg were the specialty ingredients listed above. The keg was sealed, pressurized to 30 psi, and then rolled. Pressurization and rolling was repeated once. Tasting notes will follow.

Comments:

• The specific gravity was lower than anticipated. During our boil, we reduced the vigor which then reduced the evaporation and thus concentration of the hopped wort. However, comparing the total Brix of the sweet (114) and hopped (91) worts, the hopped wort was approximately 20 points lower than expected. It is possible that our volume was larger than estimated, indicating that we reduced the heat too dramatically during our boil. This may result in higher DMS concentrations.
• Acetaldehyde was released by the yeast, as determined by the ‘cidery’ smell during fermentation, noted around 40 hours. The aroma was less noticeable around 60 hours.
• The fermentation was slower than expected. Yeast strain attenuates 70 – 75% and finishes slightly sweet (WYeast Technical Bulletin).
• Initially lactose amount was 1 lb, but was reduced due to the under attenuation observed and the yeast characteristic of finishing slightly sweet; we were concerned of having the final product too sweet.