… the Czech equivalent of a dark lager ranging in character from Munich Dunkel to Schwarzbier, but typically with greater malt richness and hop character (aroma, flavor, and/or bitterness).
I reached out to one of our favorite club member Scott “Dr. Scott” Voskuil and he has graciously provided his excellent Czech Dark Lager recipe! His reply to the request is great (give it a read):
“For your consideration, I humbly submit my recipe. It’s a single decoction, so a fun foray into that endeavor for those who are looking for the opportunity to try that.”
So here is his original (15)gallon batch recipe – And below you will find a scaled, and rounded, version of the recipe to standard (5/6)gallon batch size. – Also in the (5)gallon batch size recipe I provided some notes / information on Single Decoction – You take up “Dr Scott” on “..a fun foray into the endeavor..“
Enjoy and brew your best Czech Dark Lager for December!
Start with 21 gal total and pull off 6 gal for sparge. Added 10gm chalk. Separated the carafa and ground it with coffee grinder to dust. Added carafa to mash after decoction was pulled. Mash with 15 gal. with strike temp of 150. Normal decoction set at 158 for 20 min of the hour mash. Remove 1/3 (5gal) for decoction and boil for 45 min, then return to mash. New temp was 160 since I did not keep up the temp in the main mash while boiling the decoction. Needed to add 2 gal water to boil to correct for gravity. Slow to lauter. Volume came out right with 1/2 quart trub at bottom of kettle. Ferment at 50.
Original 15 Gallon Batch Notes: Start with 21 gal total and pull off 6 gal for sparge. Added 10gm chalk. Separated the carafa and ground it with coffee grinder to dust. Added carafa to mash after decoction was pulled. Mash with 15 gal. with strike temp of 150. Normal decoction set at 158 for 20 min of the hour mash. Remove 1/3 (5gal) for decoction and boil for 45 min, then return to mash. New temp was 160 since I did not keep up the temp in the main mash while boiling the decoction. Needed to add 2 gal water to boil to correct for gravity. Slow to lauter. Volume came out right with 1/2 quart trub at bottom of kettle. Ferment at 50.
Typical Single Decoction Info:
Step 1: Mash in Start your brew day like any other. Heat up your strike water for the first step, the saccharification rest. This step is usually between 145°F to 155°F, depending on the beer style.
Step 2: Perform the saccharification rest Allow the mash to rest for 30 to 45 minutes.
Step 3: Pull the decoction The volume should be about one third to one half the size of your mash tun.
Pull off the thickest part of the mash, meaning mostly grain with minimal liquid. The decoction should be quite thick but you should still be able to easily stir it in the decoction kettle.
Slowly bring the decoction to a boil. Make sure to stir regularly to avoid scorching.
Calculate your decoction volume to raise the mash temperature to 170°F.
Step 4: Boil the decoction Allow the decoction to boil for at least 5 minutes. Boil longer for darker beers to impart more color and caramel flavor, up to 30 minutes.
Step 5: Add back the decoction to the mash Turn off the heat on the decoction kettle.
To bring the mash up to mash-out temperature, begin transferring the decoction back to the mash tun. Use a large scoop or quart jug to transfer the boiling decoction, one or two quarts at a time. Be very careful as the mixture is still near boiling temperatures.
Stir the mash regularly and monitor the temperature. Once a mash-out temperature of 170°F is reached, hold it at that temperature for 10 minutes. Allow any leftover decoction to chill to 170°F and add that back to the mash tun.
Step 6: Sparge and proceed to the boil to finish the brew as normal Batch sparge, fly sparge, or no-sparge – whichever method you choose, and collect the full volume of wort in your boil kettle.