Mangrove Jacks M84 Bohemian Lager Yeast 10g

M84 produces authentic Czech and Bohemian lager character — soft, round, malt-forward, with very low ester production and the clean, bready finish that defines traditional Czech Pilsner. This is a true lager yeast requiring cold fermentation. You need the ability to hold 8–14°C for several weeks.

Best Suited To

• Czech Pilsner, Bohemian Pilsner
• Munich Helles, Vienna Lager, Märzen
• German Dunkel, Rauchbier

Specs

• Fermentation temp: 8–14°C primary; 0–4°C lagering (4–6 weeks)
• Attenuation: Medium-High
• Flocculation: High
• Alcohol tolerance: Up to 9% ABV
• Pitching rate: 2 sachets per 23L (cold fermentation requires higher pitch rate)

When to Choose M84

Choose M84 over M54 California Lager when you have cold fermentation capability and want traditional Czech or Bohemian lager character. M54 produces lager-like results at ale temperatures — useful when cold fermentation is not an option, but not the same result as a proper cold-fermented lager.

Choose M84 over M76 Bavarian Lager when brewing Czech or Bohemian styles. M76 is better suited to Munich styles (Helles, Märzen, Dunkel) where the malt profile is fuller and rounder. M84 suits the drier, crisper Czech profile.

Practical Notes

The diacetyl rest is not optional. After primary fermentation at 8–12°C, raise the temperature to 18°C for 48 hours before moving to cold conditioning. Skip this step and your lager will have butterscotch character that does not age out.

Two sachets per 23L is standard — lager yeasts require a higher pitch rate at cold temperatures. Pitch at 10–12°C. Do not pitch warm and crash cold.

M84 produces sulfur during active fermentation. This is normal and dissipates during cold conditioning.

Keep refrigerated. Once opened, reseal and use within 7 days.

Reviewed by the AHB Brewing Team — June 2026.