Brewing a Lager Style Beer
Though lagers are how many of us got started with our love of good beers, the amount of homebrewers who actually brew lagers, compared to ales, is relatively small. Why is this? Lager brewing requires the ability to control your fermentation temperature, and the more accurately you can control fermentation temperatures the better your end results will be. For many brewers, this means building a dedicated fermentation chamber with temperature control which can be an off-putting project for some. Other techniques which are more widely available, such as ice baths, can yield good results but can make it difficult to maintain accuracy and repeatability going forward.
Another issue with lager brewing is the patience required. Ales are ready relatively quickly in comparison to lagers which can undergo lagering periods of 12 weeks or more. This ties up a fermenter and your fermentation chamber for a significant period of time which can be off-putting.
Lastly, lagers are a very technical style of beer to brew. Though many craft beer drinkers may prefer highly hopped, or sour, or smoked beers it actually takes a high level of proficiency to brew a lager well, right from recipe formulation and throughout fermentation and packaging there is a lot to consider to make the clean, crisp and well-balanced beer people expect when you serve them a lager.
We spoke to Dave in our UK office who gave us his tips for brewing a lager at home.
‘Brewing a lager can be a huge accomplishment as a home brewer. It requires very precise control over several aspects of fermentation and unlike many ales where some dry hopping or fruit additions can cover a multitude of sins, lager brewing leaves the brewer very much exposed. The clean and balanced profile leaving very little margin for error.
As homebrewers, we shouldn’t be put off, however. Yes, lager brewing requires some technical know-how and some precise process control but as long as you follow some simple steps, a great lager is by no means out of reach.
For most styles of lager your malt bill is going to consist largely of good quality pilsner malt or possibly 2-row or lager malt. Depending on your water chemistry you may need to make adjustments to your pH and acidulated malt is a good option for this (especially if making authentic German lagers). If this is required, 1% of acidulated malt will reduce mash pH by 0.1.
Depending on style you may wish to add some specialty malts for bread crust/malt flavours such as Melanoidin, Munich or Vienna. Some brewers will also choose to add light caramel malts to their grain bill which can work well but should be avoided if making a Pilsner. Carapils can also be an excellent addition to lager styles to help with head retention and body – less than 10% of the grain bill should be sufficient.
In a lot of American style lagers, adjuncts such as corn and rice are used. They provide starch in the mash which is broken down into sugars but does not affect the end flavour of the beer (or their contribution is minimal).
In many instances, a low sulfate level is desirable for making good lagers. Many homebrewers who brew lagers will start with distilled or reverse osmosis water and then make salt additions, in particular calcium carbonate, sodium chloride or calcium chloride. Gypsum (calcium sulfate) additions are usually wrong for the style. With sulfates, levels of below 150ppm are desirable.
The water profile for a light lager may look like this;
Ca 35 – 55
Na 20 – 35
And for a Pilsner;
Mg 2 – 8
SO4 5 – 6
And a bock;
Ca 55 – 65
Na 40 – 60
SO4 35 – 55
Cl 60 – 110
There are many hop varieties that are traditionally associated with lagers. Saaz is typical for Czech pilsners and in classic examples will be the only variety used. In German-style lagers, hops such as Hallertauer or Tettnang are common and in American style lagers, Mt. Hood and Liberty are good choices.
As always you should feel free to play around with hop varieties and additions and are in no way constrained to strictly following style guidelines but if you are aiming to stay true to style then typically lagers are lightly hopped, malt-forward styles (other than Pilsners which typically have a much larger bittering addition and a BU:GU ratio of around 0.80).
Of course, there are variations on style and many breweries now produce hop-forward craft lagers or India Pale Lagers which can be an interesting take on the beer.
As a standard rule of thumb, lagers need around twice the amount of yeast that an ale of a similar gravity would need, or to be more specific, around 1.5 million cells per millilitre of wort per degree plato. If you are pitching dry yeast this simply means pitching twice as much yeast as you would normally. If you are using liquid yeast you will need to grow up a large starter of around 3-4 litres and as you grow the starter, slowly reduce the temperature until it is close to your pitching temperature, so you might start your yeast starter at 18C/64F but by the time you ramp it up to 4 litres it should be between 7-9C (45F-48F).
Many homebrewers choose to pitch warm because it can result in a shorter lag phase and means less yeast is required however, a warmer pitching rate will lead to greater production of esters, fusel alcohols and diacetyl which are undesirable in most lager styles to any great degree.
With most lager styles, the fermentation profile is very clean although some diacetyl or light yeast esters can be acceptable. The production of these flavours is largely controlled through the brewing process.
There are many different approaches to fermenting lagers, all of which can produce good results so if you have a process that works well for you it is fine to stick with it. This is just a simple step by step process for a typical lager fermentation;
- Once you have completed your brew, chill the wort down to around 8 or 9C (46.4F -48.2F). If you are using a yeast starter you should have grown this to a sufficient level prior to pitching.
- Pitching cold can increase lag time. The colder temperature enables the beer to absorb more CO2 before it is pushed out of suspension, creating the krausen so if you do not see signs of fermentation as soon as you would expect based on your ale brews, don’t panic.
- Allow primary fermentation to take place. As best as possible keep the temperature between 9-11C (48-52F) or within the range recommended for your chosen yeast strain. At these temperatures primary fermentation is likely to take longer than usual so expect this to last between 3 and 4 weeks.
- After primary fermentation, transfer your lager to a secondary fermenter being careful to minimise oxygen pick up. This begins the lagering phase which refers to an extended period of cold storing. This phase can last from two right up to twelve weeks. This clears up the beer, both in terms of appearance and flavour. Solids will drop out of suspension leading to a brighter looking lager and diacetyl produced during fermentation should be cleaned up by the yeast.
- As lagers undergo extended periods of time in fermenting vessels when it comes to bottling your lager you may wish to pitch a small amount of extra yeast to ensure the beer carbonates properly.
Other Considerations for Brewing Lagers
- In a lot of instances when brewing a lager you are aiming for a light and crisp beer. To achieve this, either mash at the lower temperature end (65c/148F) or mash very low (62C/144F) and then ramp up the temperature to 69C (156F). This two-step mash ensures you target both alpha and beta amylase, resulting in a more fermentable wort and a lighter bodied beer.
- DMS (dimethyl sulfide) can be present in a lot of lager styles to some extent but in any great quantity it is considered an off flavour. Unfortunately, pilsner malt and other very pale malts contain high levels of the pre-cursor to DMS which can impart a creamed corn type flavour into your lagers. To avoid this you should boil your lagers vigorously and uncovered for 90 minutes.
- Diacetyl is another off flavour that is naturally produced by yeast as part of the brewing process. Yeast will naturally reabsorb diacetyl towards the end of fermentation but this can be a slow process when you are fermenting cold. To help with this, many brewers will raise the temperature of their beer to between 18-20C (50-55F) for the last two days of fermentation to help clean up diacetyl before lowering the temperature again for the lagering phase.’
So there you have it, some tips for creating a recipe for a lager and how to brew one successfully. Have you attempted a lager brew yet? What was your process? Let us know in the comments below.