Brewing Lager Beer (Club Guide)

Based on a Lauter Day Brewers talk by Paul Konopelski (Bohemian Brewery).

TL;DR: Start with soft water (RO + salts), pick classic malts, mash simple (or go fancy with rests/decoction), ferment cold with a healthy pitch, give it a diacetyl rest, then lager near-freezing for at least two weeks. 

Ingredients that matter

Water

  • RO + salts or carbon-filtered works great.
  • Aim for lower alkalinity and lighter mineral load in pale lagers; adjust pH and your SO₄:Cl ratio to taste (a touch more chloride for roundness, more sulfate for snap). 

Hops

  • Stick with noble (Hallertau, Tettnang, Saaz, Spalt) or new-school Euro (Mandarina Bavaria, Hüll Melon) for clean bitterness and delicate aroma
  • IPL is the exception—go bolder if you’re chasing hop-forward.

Malt

  • Pilsner malt (1.5–2 °L): light, low toast, higher DMS precursor (SMM) → boil longer than 60 min.
  • Vienna (3–3.5 °L): can be 100% of grist; adds light honey/toast.
  • Munich (5–6, 9–10 °L): use higher for darker, richer lagers.

Yeast

  • Any true lager yeast works; pitch big and ferment cool.
  • Hybrid strains (Kölsch, Alt, steam/California common, even Cry Havoc) can make lager-like beers if you can’t run at lager temps.

Mash options (simple to old-school)

  • Single-infusion: totally fine for clean modern lagers.
  • Step program (optional):
    • Acid rest 95–113°F (35–45°C)
    • Protein rest 113–138°F (45–59°C)
    • Conversion: β-amylase 140–149°F (60–65°C) → drier; α-amylase 150–158°F (66–70°C) → fuller
    • Mash-out 162–169°F (72–76°C)

Decoction (optional but fun): Pull a thick portion, boil it, and return to the main mash. Benefits: richer malt depth via Maillard/caramelization, and you can hit rests without direct heat.

Fermentation: where lagers are made

  • Temp: 45–55°F (7–13°C).
  • Pitch rate: about 1.2 million cells / mL / °P (for a 5-gal ~1.048 lager, that’s ~275B cells—think 2× 11–12 g dry packs or a healthy starter).
  • Lagers produce fewer esters/phenols and more sulfur; the sulfur scrubs out during active fermentation.
  • A bit of yeast nutrient helps.

Diacetyl (butter) plan

  • All yeast make it; many lager strains produce more and clean it up slower.
  • Near the end of fermentation, raise to ≥60°F (15.5°C) for a diacetyl rest, then crash.

Lagering (the namesake step)

“Lager” = store. After fermentation and diacetyl rest, hold the beer cold—ideally 30–38°F—for at least two weeks. You’ll get clarity and polish in flavor. Longer is often better.

5-Gallon Quick Start (bookmark this)

  1. Water: RO base + light salts; keep alkalinity low.
  2. Grain: 95–100% Pilsner for Helles/Pils; Vienna/Munich for amber/darker styles.
  3. Boil: 70–90 min for Pilsner-heavy grists (DMS).
  4. Hops: gentle bittering, noble late.
  5. Chill & pitch big: oxygenate; hit 45–50°F.
  6. Ferment: start 48–50°F, let rise to 52–54°F as activity peaks.
  7. Diacetyl rest: when ~2–6 points from FG, raise to 60–62°F for 24–48 h.
  8. Lager: drop to 34°F for 2–4+ weeks. Package cold and carbonate.

Troubleshooting quickies

  • Sulfur aroma: normal mid-ferment; give it time, vent CO₂, and it fades.
  • Butter/butterscotch: extend the diacetyl rest; don’t rush the crash.
  • Haze in a pale lager: confirm complete fermentation, fine if desired, then lager colder/longer.

Credit: Adapted from the presentation “Brewing Lager Beer” (slides by Paul Konopelski, Bohemian Brewery).