(29) Sunday, October 2, 2011 Brew Day — Dry Stout

You ate already. You're a night horse.

Today’s brew is Jamil Zainasheff’s Dry Stout recipe. For those of you with a copy of Brewing Classic Styles, this is the Cerveza de Malto Seco. Since this recipe is already available online, I am going to go ahead and document here what I am brewing. Perhaps you will feel encouraged to go buy your own copy of the book.

Original Gravity: 1.042 SG
Boil: 60 minutes
Mash: Protein rest for 15 minutes at 120 °F (49 °C) then saccharification rest for 60 minutes at 150 °F (64 °F).
Fermentation: Ferment at 65 °F then do a diacetyl rest.
Serving: Serve at 52–55 °F (11–13 °C) with 1–1.5 volumes of CO₂.

Grain Amount
Thomas Fawcett & Sons Halcyon 70%
Flaked Barley 20%
Briess Black Barley 10%
Kent Goldings 60 min. 38.5 IBU
Wyeast 1084 Irish Ale 162B Cells

Despite its apparent simplicity, BCS lists this as a recipe for advanced brewers. I believe the reason is that it calls for a two temperature mash. If you do infusion mashing in an unheated cooler — as I do — this will need multiple infusions. BCS offers no guidance on this.

In How to Brew, John Palmer suggests one possible reason for the stepped infusions mash.

The typical Protein Rest at 120–130°F is used to break up proteins which might otherwise cause chill haze and can improve the head retention. This rest should only be used when using moderately-modified malts, or when using fully modified malts with a large proportion (>25%) of unmalted grain, e.g. flaked barley, wheat, rye, or oatmeal. —John Palmer

In this case, the base grain is fully modified — it already received the benefit of the enzymes activated in this temperature range during the malting process — but flaked barley and black barley are not malted. Performing a protein rest allows the protease enzymes to work on the proteins in unmalted grains to improve head retention and cut haze.

I might speculate that the roasting process probably denatured all the proteins in the black barley and that we should not consider them in this process, leaving us at only 20% of the grain bill that would benefit from a protein rest, which is below John’s threshold, which itself is probably more of a rule of thumb. In fact, the online version of the recipe calls for a single temperature infusion mash. Nonetheless, I am going to do a double infusion mash with a protein rest because to some extent I chose this recipe to push the boundaries of my abilities and I have never done this before.

This is my 29th brew day since I got back into home brewing 3½ years ago. I feel that I have gotten reasonably adept at running through my process on my system with my recipes. That said, I really only know my basic single infusion mash, batch sparge, moderate gravity, ale fermentation with highly flocculant yeast. There are a lot more topics to learn, and multiple infusion mashing is one. It does not hurt that I happen to be fond of Dry Stout. Gretchen is not, so I still need to have the house ale on hand to maintain marital bliss.

To figure out how to do the multiple infusion mash, I went to the library and I picked up a copy of A Handbook of Basic Brewing Calculations, by Stephen R. Holle.

(Eq. 1)

T_{\mbox{E}}=\frac{\left( 0.4\; \times \; W_{G}\; \times \; T_{G} \right)\; +\; \left( W_{W}\; \times \; T_{W} \right)}{0.4\; \times \; W_{G}\; \times \; W_{W}}

TE is the equilibrium temperature. This is the temperature you are trying to achieve with the first infusion starting with dry grain.
WG is the weight of the dry grain.
TG is the temperature of the dry grain.
WW is the weight of the water you will infuse.
TW is the temperature of the water you will infuse.

(Eq. 2)

HC_{M}=\frac{\left( 0.4\; \times \; W_{G} \right)\; +\; W_{W}}{W_{G}\; +\; W_{W}}

HCM is the heat capacity of the mash.

(Eq. 3)

W_{BW}=\frac{\left( HC_{M}\; \times \; W_{M} \right)\; \times \; \left( T_{T}\; -\; T_{M} \right)}{T_{BW}\; -\; T_{T}}

WBW is the weight of boiling water to infuse.
WM is the weight of mash.
TT is the target temperature.
TM is the mash temperature.
TBW is the boiling water temperature.

You can use equation 1 to determine an amount of water at a temperature that will give you the equilibrium temperature you want for the initial rest.

You can use equations 2 and 3 to determine an amount of boiling water that will give you the equilibrium temperature you want for the second infusion.

My calculations indication that one way to get my 10 pounds of grain at 68 °F to 120 °F, is to add 3 gallons of 128 °F water. Then to raise 10 pounds of grain and 3 gallons of 120 °F water to 150 °F, is to add 2 gallons of 203 °F — nearly boiling — water. That will also give me my normal 5 gallon mash.

I made the same calculations in BeerAlchemy and came up with one addition of 3 gallons at 129 °F and one of 1.71 gallons of boiling water. The later is smaller than mine since I am expecting to lose heat transferring to the mash tun, so I need more volume.

I typically lose 9 °F transferring from the hot liquor tank to the mash tun. That means my HLT temperature needs to be 137 °F for the first infusion and 212 °F — boiling — for the second.

For lack of a better suggestion, I am using my standard water adjustment that gives me about 100 ppm Calcium and a balanced Sulfate-to-Chloride ratio. Bru’n Water indicates a room-temperature pH of 5.4 with this recipe.

7:15 It’s snowing!

9:00 Gas is on. Yeast is smacked.

9:20 Slightly overshot my strike temperature. I’m going to go ahead and transfer and then stir until the temperature drops back down a bit.

9:37 Strike water has reached 129 °F. Adding grains and mash salts. Temperature stabilized at 120 °F. Setting a 10 minute timer.

9:50 Added 2 gallons of boiling water. Temperature stabilized to 149 °F (after some mixing). Setting a 60 minute timer. Sanitizing my carboy in the mean time.

10:55 The mash is complete. The temperature of the mash dropped to 147 °F. Proceeding to vorlauf and lauter.Almost forgot to close the valve on the boil kettle!

11:04 Collected 3⅜ gallon of first runnings with a gravity of 1.050 at 106 °F, or 1.057 SG corrected. Proceeding to sparge. The sparge water temperature was 178 °F and stabilized to 160 °F in the mash tun. The boil salts are in.

11:20 Collected an additional 3 gallons in the sparge for a total boil volume of 6⅜ gallons. The gravity of the second runnings were 1.015 SG at 118 °F, or 1.025 SG corrected. Heating to boil. Boil gravity is 1.032 SG at 115 °F, or 1.041 SG corrected. Target was 1.036 SG. Overall efficiency is 70%.

11:26 Heating to boil.

11:55 Boiling. Waiting for hot break.

12:00 Hot break has subsided. Bittering hops are in. Setting a 60 minute timer. Cleaning my mash tun.

12:45 Immersion chiller, yeast nutrient, and Irish Moss are in.

1:00 Flame out. Chilling.

1:28 Chilled to 68 °F. Whirlpool and cover. Breaking for lunch.

1:55 I’m back! Draining to the carboy. Original gravity is 1.051 SG at 64, or 1.051 SG corrected. Target was 1.042. The final gravity volume was 5⅜ gallons. The gravity sample tastes great.

2:15 Drained. Aerating.

2:20 Aerated.

2:30 Beer is in the fermentation fridge at 63 °F. Thermostat set for 66 °F. Pitched two activator packs manufactured September 6, 2011 (Mr. Malty says 78% viability, or 156B cells).

3:40 Done.

Monday Evening (10/3) This morning, the beer was down to 58 °F. It was fermenting, but much lower than I wanted, and 4 °F below the range for the yeast. I warmed the beer to 62 °F — the bottom of the specified range for the yeast — but that was all I had time for before work. When I got home tonight, it was still fermenting at 62 °F and had significant kräusen, but not much vigor. I am applying additional heat in hopes of bringing it up to 65 °F.

Saturday (10/8) I moved the carboy out of the refrigerator and set my FermWrap for 65 °F. I’ll raise the temperature slowly to 71 °F for a diacytl rest for a few days.

Sunday (10/16) Kegged. Final gravity is 1.010 SG at 68 °F. Corrected gravity is 1.011 SG. Target was 1.010 SG. The gravity sample tasted great. Warm and flat, but otherwise very nice. As brewed, this beer is 5.3% ABV.

Thursday evening (10/20) First glass has no apparent sediment. Roasty, if slightly acrid, aroma. Black color. Dark brown head. Slightly under carbonated. Delicious. Easy drinker. Slightly thin, which I attribute to the undercarbonation. Balanced.

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