What is Lagering?
Lagering is more than just “cold storage.” It’s a brewing process built around cold fermentation, cold storage, and a family of beer styles that benefit from it.
Cold Fermentation & Storage
- Ferment cool (typically 45–55°F / 7–13°C) with lager yeast
- Store near-freezing after fermentation to clarify and smooth the beer
Lager Styles
Classic styles:
- Standard American Lager
- Pilsner
- Vienna Lager
- Oktoberfest
- Helles
- Dunkel
- Doppelbock
- Baltic Porter
Hybrids:
- California Common
- Kölsch
Recipe Formulation
Pale lagers often use adjuncts such as rice, corn, or sugar.
These reduce free amino acids (FAN), which in turn reduces production of certain flavor compounds from amino acid metabolism.
Chilling Wort
Wort should be cooled to near fermentation temperature before pitching yeast.
This may require an ice bath, a pre-chiller, or both.
Yeast Selection
- Ale yeast: Saccharomyces cerevisiae
- Lager yeast: Saccharomyces pastorianus
Primary considerations for lager yeast are diacetyl production and how the strain enhances maltiness or fruitiness.
Examples:
- Wyeast 2124 – Bohemian Lager
- Wyeast 2001 – Urquell Lager
- Wyeast 2278 – Czech Pils
- Wyeast 2112 – California Lager
Pitching Rates
Lagers typically require 2–3 times the pitching rate of ales.
Starters can be produced at normal fermentation temperatures.
Fermentation Temperature Control
With refrigeration:
- Johnson or Ranco controllers
- Temperature probes
- Thermowells
Without refrigeration:
- Ice bath
- Wet towels
- Evaporative cooling
Diacetyl Rest
During yeast growth, valine production creates an intermediate called acetolactate.
This is a precursor to diacetyl (buttery flavor).
A diacetyl rest ensures yeast re-absorbs diacetyl before cold storage:
- Begin when beer is ~5 gravity points above terminal
- Raise temperature by ~10°F for 24–48 hours
Adding yeast nutrient can reduce the need for yeast to make valine, minimizing diacetyl risk.
Lagering
After the diacetyl rest, drop the beer to near-freezing.
This allows:
- Yeast flocculation
- Clarification
- Minimization of aging effects
Typical duration:
- About 21 days for standard lagers
- Longer for stronger beers