Lagering Beer at Home

Most of us grew up drinking bottled lager beer. Hence wheat, IPA, and craft ales from microbrewery feel very different to us. Making a batch of lager is one of the biggest quests for a home brewer. It requires serious investment in temperature control, patience, and equipment.

What does Lagering Mean

Lagern is a German word that means to store. While ales can be brewed and served in a week or two, a typical lager requires 45-60 days of patience to get perfect. Hence, for a home brewer getting their hands dirty on lagering, please understand this will be pushing the envelope of your skills in terms of patience, equipment and hardwork.

80% of the bottled beers are lagers. Even the refrigeration industry owes its origin to lagering. 1mX1mX1m blocks of ice weighing about 1ton was pushed into brewing ice caves every day. Even in the modern refrigeration industry, they use the same nomenclature as used by beer brewing caves that made lagers. That being said, most people don’t understand the difference between beer and ales.

All traditional beers were ales and not lager. Only in the late 15th century lagering start to take prominence. The taste of people gradually shifted from ales to cold brew beer or winter beer. Towards the end of prohibition (less than a century ago) is when bottled beer started taking prominence. Lagers had no deposit in the bottle, no haze, and crisp flavors. This made them ideal candidates for industrial beer. The fact that it took 40-60 days to brew and mature meant that small local breweries were driven out of business and only industrial setup would dominate.

What does it mean to Lager

To summarize, a Lager beer should:

  1. Brewed with a bottom fermenting yeast
  2. Brewed at 4-10 degrees Celsius. California Steam Ales or craft beer brewed at 15 degrees or higher don’t qualify. Even though some of them have similar taste and appearance.
  3. Should be clear of any haze. Also, should have very crisp clean flavors. Any brewer who has matured and fermented their beer for 45-60 days should never face haze problems.

Where did Lagering Originate

Lagering is a form of beer brewing that uses a bottom-fermenting yeast. This yeast is Saccharomyces pastorianus and it has a hydrophilic cell wall as compared to hydrophobic cell wall of Saccharomyces cerevisiae. As a result, this yeast cell does not attach itself to the CO2 produced and floats to the top.

We find references to lagers and bottom-fermenting yeast as early as 14th Century Germany (Nuremberg, Franconian and Bavarian). However, the strains were never properly studied or classified. Modern scientists agree that lager yeast is a hybrid of ale yeast and Saccharomyces eubayanus. Saccharomyces eubayanus is native to South America. Now since South America was not discovered till Mid 15th Century by Christopher Columbus it is hard to pinpoint when exactly the leap in bio-engineering lead to the creation of this new yeast. Also, how a tree bark yeast from South America boarded a Spanish ship and how did it make its way to the Belgian Brewing Vats is open to speculation.

What people forget to mention is the cheap availability of Glassware in the rise of Lagers. In the 17th Century, modern glassware technology was developed in the. This allowed the beer drinkers to see their beer for the first time. Otherwise, the froth on the top in wooden mugs did not allow for an inspection on the beverage haze.

Depending on which tavern, microbrewery, pub, or cafe you drink from, you will hear a different story. Like all drinking stories, it will be very vivid, full of adventures and helps you pass a good time.

Brewing Lager at Home

The three famous lagers would be Pilsner, altbier, and kölsch. However, most home brewer often start with clone recipes for commercial bottled beer. It does not matter how you end here. The important question is “Do you have all that it takes to make a lager?”

1. Lager vs Ale Dry Yeast Culture

corny keg fermenter
lagering with airlock

Commercial lager beer typically require 6 to 12 weeks of the process. You need a yeast that does both, survive the cold temperatures and complete the fermentation. It should also not produce any stressed notes.

There are three styles yeast for lagering at home:

  1. Choosing a crisp clean ale yeast. For e.g. Kölsch, IPA yeast strains, or any yeast that is low on esters and high flocculation. Brewers will make the normal ale beer but spend extra time in the secondary and lower temperature there. The advantage is that it is a faster and simpler process. The 2 weeks of cold crash will help mimic all the properties of a good lager. Especially if the hop flavors are dominant.
  2. Use a lager yeast and ferment it at ale temperatures. This way you are not cheating on the yeast strain. However, your fermenter is not occupied forever.
  3. Watery strong beer: Some brewers would replace their grain bill/malt with sucrose or glucose. By doing so, the residual malty taste associated with ales go away. The resulting beer will be watery and can mimic lagers. However, just like the commercial strong beers, this would give a really nasty hangover.
  4. Making a true lager (right yeast, right temperature, and right duration). This is what we will discuss today.

Buy Related Products

First thing to note is the pitch rate. Commercial breweries recommend 1 million cells/°Plato/ml. This is roughly two to three times more than what we use for ale fermentation. So either you buy sufficient yeast or make a starter culture. A 20 Liters batch would need roughly 240 billion cells. Instructions to make a stir plate at home can be found at arishtam free video tutorials.

Second is the wort oxygenation. Ale and wine yeast are top-fermenting. This means that they are able to rise to the top in the Krausen and get the required oxygen to stay healthy. Bottom fermenting yeast does not get the same liberty. Also, the solubility of CO2 drastically increases at lower temperatures. This means access to oxygen becomes very difficult. An oxygenation wand helps maintain 8-12 ppm of O2 that is needed for establishing the healthy yeast colony.

Third is the adequate amount of yeast energizer. Stuck fermentation is often the bane of low temperature lager brewing. So energizer will help ensure that your beer does not end up like a hoppy sweet malt beverage for kids.

Temperature Control in Lager Fermenter

Lagering without refrigerator/fridge is nearly impossible unless you live in the Himalayas and want to brew in an ice cave. Please buy a chest freezer or keezer and attach a thermostat on it. Test your thermostat a couple of times to record the lowest temperature and highest peak. If you feel that the 4-degree setting overnight leads to slushing (semi-solid ice water mixture) by the morning then definitely the temperature setting needs calibration. Also, the thermostat will record the temperature around the problem. Your fermenter might be slightly away from it. Plus the beverage temperature might be higher than the air temperature(as yeast metabolism produces heat and alcohol). LCD thermometer strips help in finding which fermenter is hot and which is not.

Do note that Glass and thick HDPE are insulators which may not be able to cool the liquid fast enough. As a result, you will end up with warmer fermentation. The heat from the fermentation will not be removed by the thick insulator walls fast enough. Then later on when you want to increase the temperature, insulator might prevent a correct diacetyl rest.

Buy Related Products

Will Beer in my Keg Freeze

  • Beer freezes at -10 Degree Celsius. So unless your thermostat is really faulty, its hard to freeze beer.
  • The advantage of a corny keg is that it can withstand 120 PSI of pressure. So unlike a glass bottle, keg will not burst in your freezer
  • If you still manage to freeze the beer, it will most likely turn into a slush. There is a technique call Freeze distillation which brewers use to make really strong beer and wine. Essentially the water freezes first and leaves behind the alcohol (anti-freeze). This leads to higher and higher concentrations.

Diacetyl Rest for crisp tasting lagers

After about 3 weeks, the fermentation rate will slow down considerably. When you are about 0.005 to 0.008 specific gravity point away from your final desired gravity, its time to take care of the off-flavors. With pressure fermenting in conical fermenters this lagering time can be reduced further. However, lagers are very unforgiving when it comes to off-flavors. The two biggest are:

  1. Maltiness is an indication of incomplete fermentation. It could be due to a variety of reasons but usually higher gravity and low yeast cell count/health. Impatient brewers also make sweet lagers if they don’t wait long enough for fermentation to complete.
  2. Diacetyl and acetaldehyde.

For Diacetyl rest, the brewer will increase the temperature to ~15 Degrees Celcius (to even 18 in some recipes) for up to 2 days. Raising this temperature helps complete the fermentation. The residual complex sugars breaks down leading to a drastic reduction in gravity. The off-flavors especially the 30% diacetyl (buttery flavors) and 20-70% acetaldehyde (raw green apple flavors) are also absorbed back.

There is some research claim that this 2-day rest even leads to a reduction of lactic acids, acetic acid. Also, some enzymes and biochemical reactions that are temperature sensitive get triggered. This leads to the signature taste of the lager beer. Furthermore, complex maltodextrins and maltotriose gets broken down leading to ~5 gravity point reduction.

Also, these 2 days is the best time to harvest yeast and then do pressure ferment. This will allow natural CO2 to carbonate the beer.

Conditioning or secondary fermentation

Lagering also helps precipitation. All residual and suspended particles settle to the bottom due to the drastic slowing of Brownian motion. Some of the large- molecular-chain proteins that link up with grain and hop phenols, such as tannins also separate. Overall the haze in the beer gets reduced drastically. Even the SO2 which leads to vegetal notes due to dimethyl sulfide is reduced. Some of the hop-derived mercaptan or skunkness is reduced during the prolonged conditioning of the lager beer.

How to Handle yeast cake?

If you are using the conical fermenter or Fermzilla, then opening the dump valve will help you get rid of the yeast cake. Otherwise, we recommend transferring from primary to secondary. This is usually done just before the 2-day Diacetyl rest and secondary conditioning. The biggest advantage of this transfer is that the sediment is permanently removed. The yeast can no longer autolyze and introduce off-flavors. Also, any amount of agitation will not cause a cloudy beer.

When to Bottle or Keg a Lager

Personally I don’t recommend bottling lager. The refermentation due to priming sugar will murky all the hard work in clearing up the lager. Here is the typical home brewer lager chart:

  1. Primary fermentation for 20-25 days.
  2. Transfer to the secondary and rest for 2 days.
  3. Pressure conditioning for another 10-14 days.
  4. Then serve.

If you do need to bottle for competition or gifts, then please use a counter flow pressure filler or carbonation cap lids. This way it will be easier to pressurize the bottle.

Buy Related Products

Lager vs Ale vs Pilsner

Pilsner is a Czech style Pale Lager with copious amounts of Saaz hops from Žatec . This iconic beer got its name from the Czech town of Plzeň where Pilsner Urquell brewed this recipe first. The brewery still exists and has a museum tour for patrons. Its iconic water tower still dominates the landscape. The city is the home to Skoda company and is one one of the biggest industrial towns of East Europe.

Image: wikimapia

Here is a map of searches for these three keywords. As you can see the lagers and pilsner are gaining awareness. However bottled beer (which is also a lager) and wheat craft beer continues to dominate the market.

Buy Related Products


  1. Prasanna Akkalkotkar

    Hi Ankur,
    Please suggest me the right yeast and hops for brewing beer in Pune (at room temp of around 30 deg at present)

    Or shall I brew it at lower temp. in refrigerator?

    1. Prasanna you will a precision temperature controller for lager. However you can make a decent room temperature beer using KVEIK or Saison yeasts.

Leave a Reply

Your email address will not be published. Required fields are marked *