Próst! How to Ferment a Lager Beer

Written by Tristan Fanning on September 12, 2021

Lager beers are making a comeback in the world of craft beer and as a home-brewer you have the ability to make stunning lagers that can be hard to find in the commercial beer world.   This is a step by step guide on how to ferment your lager beer along with some tips and tricks to keep your wort in the right temperature range without expensive equipment.

Lager Fermentation Step 1 starts on brew day:

Chill your wort to as cold as you can get it as rapidly as possible while it is still in the kettle.  This can be achieved with a wort chiller, or an ice bath in your sink. Since this is a lager, it is recommended to chill all the way to the low 50s before adding your yeast, but if that’s not possible, it’s not the end of the world.

Top your beer up to 5 gallons with more water if needed. Hint: Using cold, clean water can help you finish chilling the wort to the ideal 50*F.

Once you have gotten your wort as cold as your equipment will allow, Gently pour your wort into your primary fermenter being careful to leave as much of the sludge at the bottom in your kettle as possible. 

Wort Chiller

Step 2: Pitch your yeast

Vigorously stir your wort to introduce as much oxygen as possible into the wort.  This is the ONLY time you want to get oxygen in your beer.

Put your unopened yeast pack(s) into your bucket of sanitizer.  Place your sanitized hydrometer into your wort and take an original gravity reading.

Sanitize your Scissors and yeast pouch by dipping in sanitizer.

Once your wort is between 50-60 degrees F pitch your yeast by pouring your yeast into the wort. Important, if your wort is outside of this temperature range do not pitch the yeast until it is in the temperature range.

Seal the top of your fermenter and put an airlock partially filled with sanitizer into the hole on top.

Lager Yeast

Step 3: Ferment for 7-14 days

Keep your wort in the 50-55 degree range for 7-14 days while the beer ferments. There are a few ways to do this.

  • Put the fermenter in a cool part of the house such as the basement or the garage in the cooler months.
  • Keep the fermenter in a water bath
  • Put a wet T-shirt or over the fermenter (this relies on the magic of evaporative cooling to keep the fermenter cool.)
  • Rent lagering space at Perfect Brewing Supply

When the airlock stops bubbling and the yeast cake has dropped to the bottom, remove the lid and take a reading with your hydrometer
If you have reached your desired final gravity (give or take a couple points) you are ready to rack it over into your secondary fermenter.

Rent Lager Fermentation Space

Step 4: Lagering time!

What sets lager beers apart from thier Ale counterparts is their incredible clarity and crispness. This is where that clarity is generated, the lagering process. Lagering is a fancy term for cold storage which allows the beer to become crystal clear.

Use your auto-siphon to gently rack the beer into your secondary fermenter, leaving as much of the trub behind as possible. For lagers your secondary fermenter can be a carboy or your serving keg.

Seal the fermenter and place it in a cold spot for the lagering phase. Traditionally, lagers are stored in the 32-40F range for 4-6 weeks. The longer the beer is lagered, typically, the cleaner and crisper the beer will get. Ideally, brew another beer now so the wait is less excruciating next time.

Secondary Fermenter