Geoff Humphrey's BrewBlog > BrewBlogs

Czech Dark Lager

Batch #:

2023-06

Batch Size:

11.00 gallons

Boil Time:

90 min

Brew Date:

May 28, 2023

Statistics

OG:

1.051 12.6° P

FG:

1.014 3.6° P

Real Extract:

5.2° P

Attenuation:

71.4% Apparent
58.7% Real

Carbonation:

2.5 volumes

Color:

24.9SRM

IBU:

26.6

BU/GU:

0.52

ABV:

4.9%

ABW:

3.8%

Calories:

168 12 oz

Fermentables

Amount	Fermentable	% of Grist
11.50 pounds	Bohemian Pilsner Weyermann	52%
7.25 pounds	Munich II Weyermann	32.8%
2.25 pounds	Caramunich II Weyermann	10.2%
1.12 pounds	Carafa Special II Weyermann	5.1%
22.12 pounds	Total Fermentable Weight	100%

Hops

Amount	Hop	Time	Use	Form	AA
1.75 ounces	Saaz	90 minutes	First Wort	Pellet	3.0%
1.25 ounces	Magnum	60 minutes	Boil	Pellet	10.8%
1.50 ounces	Saaz	20 minutes	Boil	Pellet	3.0%
1.00 ounces	Saaz	20 minutes	Aroma	Pellet	3.0%
5.50 ounces	Total Hop Weight

Non-Fermentables

Amount	Non-Fermentable	Type	Use	Time
0.50 g	Epsom Salt (MgSO4)	Water Agent	Mash	0 minutes
8.00 ml	Lactic Acid	Water Agent	Mash	0 minutes
0.25 g	Epsom Salt (MgSO4)	Water Agent	Sparge	0 minutes
3.00 ml	Lactic Acid	Water Agent	Sparge	0 minutes

Yeasts

Name	Lab/Manufacturer	Product ID	Form
Urkel	Imperial Yeast	L28	Liquid

Equipment Profile Geoff's Electric Equipment

Batch Size:

11.00 gallons

Boil Volume:

13.23 gallons

Boil Time:

90 minutes

Evaporation Rate:

7.56% per hour

Hop Utilization:

100%

Trub Chiller Loss:

0.26 gallons

Mash Profile Decoction, Single - Undermodified Malts - Batch Sparge

Ideal Grain Temp:

68°F

Mash Steps

#	Name	Type	Time	Temp.
1	Protein Rest	Temperature	35 minutes	122° F
2	Saccharification	Temperature	45 minutes	154° F

Fermentation and Aging

Primary:

10 days @ 52° F

Secondary:

3 days @ 62° F

Tertiary:

30 days @ 34° F

General Info

Start with RO water if possible or target a soft water profile (not Pilsen - that's too soft).

Cold steep Carafa for 24 hours in 1 quart of water (use a grain bag). Add liquid to boil.

If not using floor malted pilsner malt, use the well-modified decoction regimen (skip the protein rest and start at low saccharification temp of 132 - adjust decoction amount or step mash to target 153 full re).

Derived from:

Bob Hall's 2015 NHC presentation
Mad Fermentationist
Ivan Chramosil interview (U Fleku former brewer)
Make Your Best Czech Dark Lager (Beer and Brewing)

Notes from first brewing session:

pH at 5.67 at 20 minutes. Added 1/2 tbsp of lactic. Brought pH to 5.41. Acidity in roasted grains will take care of the rest.
Mash does NOT include Carafa. That was cold steeped and added to boil.
Mash temp after decoction was 151 - 3 degrees lower than target. Added 1.5 gallons of 190 F water to bring to 153.4.

Tmavé Pivo