An Overview of Brewing Lager; its processes, raw materials and history

NigelGibbons
Posted by
Nigel Gibbons
on 08/08/20

Nigel is the Southern Sales Account Manager for Crisp Malt and lives in Suffolk.

Read More
 

As long ago as the 1500’s only lager was brewed in Bavaria. The beer was often stored in caves at low temperatures and it was the yeasts that could survive in this harsh environment that became the norm in brewing.

Furthermore, in this region, the malting barley available was not of particularly good quality having higher TN’s and Proteins. The beer was dark as a result of poor kiln control with coal or wood direct-fired heating in the malting process and thus the process and local raw material largely dictated what the finished beer would be.

The lagering (storage) process could take months to create the finished beer at these lower temperatures unlike the much shorter timeframe when producing a cask Ale. At this time the process did not lend itself to the industrialisation of the product and therefore remained a niche beer style.

Over many years, farmers, maltsters and brewers have benefitted from their experiences and knowledge as well as seeing improvements in brewing and yeast technology. This blog delves into some of the reasons that have influenced this product over many years. It also looks at what maltsters can do to help the beer enthusiast create the best beer by producing a wider range of lager malts.

In 2020 there is a wonderful selection of Lager/Pilsner beers for the consumer to choose from. The Beer has evolved and at Crisp Maltings we too have changed to meet that challenge. If you are looking for an authentic Pilsen Malt from our Tivoli Maltings in Germany, our Europils or an Extra Pale Malt (Lager malt) utilising a Spring or indeed a 2 row Winter Barley variety from the UK, Crisp Malt can help you create something that is subtly different in order to produce styles of beer that you can be proud of.

The Malting Processes

Malt for Brewing | Crisp Malt Floor Maltings in Norfolk, UK
 

We now look at how different malting processes have an influence on brewing lager beer.

Traditional lager would have been more flavoured than current lager brands. It was also darker due to using malt which had been produced by a direct heat source when burning either wood or coal. This often produced an acrid smoke hence the colour.

In the 1700s coke replaced the aforementioned fuels. It was cleaner and better, but it produced potential carcinogens. Today, burning sulphur combats this problem on Crisps No19 Floor Maltings in Norfolk, UK. The process is still being used successfully today.

Fast forward and in modern times, indirect heating is used, and it is often gas-fired. This sends heat down pipes and radiators providing a different type of heat that is gentler. It is also more energy-efficient as well as being more environmentally friendly. This cleaner, more controllable fuel enabled the maltster to produce paler coloured malts. For more information on the malting process, read it here.

As the heat source changed so did the beer style. In 1842 Pilsner Urquell was the first brewery to produce a light Pale Pilsner Lager using this new improved malt and was the variety Hana which Crisp Malt has resurrected and is available in limited quantities. Czech Saaz hops were also used and the Pilsner beer was born!

This Pilsner is what many modern drinkers would recognise as a modern lager although this Urquell product has more diacetyl (butterscotch) flavour than most other beers. This is due to the yeast type used (H-Strain). Many people actually like this flavour, but it is not to everyone’s taste.

 

The Development of Yeast and Technology in lager production.

 

Just as different malts play a big part in the finished lager, so too does the yeast play a huge role in the quality and style of beer. It also influences flavour more than most people imagine.

By understanding the different attributes of yeast, brewers develop their knowledge and use strains that work for their individual processes and brew kit.

This learning curve and understanding of a brewer’s raw materials has been a long one. However, as we discover below, our knowledge suddenly accelerated thanks largely to 3 people during the 1800’s.

For many years The Carlsberg Brewery had been at the forefront of beer production and innovation. In 1845 the Spaten (Munich) Brewery sent Carlsberg some yeast that was a combination of 2 different strains, an Ale type – S. Cerevisiae and a strain which was finally found to have come from South America. This was a lager yeast named S. Eubayanus and it shares 95% similarity to the lager yeast genome.

The problem with the Spaten yeast was that one strain could become dominant and the negative attributes in brewing could take over.

This Patagonian Eubayanus yeast is cold-tolerant which is good but it is POF positive which creates a phenolic off flavour as found in some Belgian beers. It is also Maltriose negative which means that it won’t ferment the three glucose unit sugars and this is not typical of a lager. Fermentation is slow.

As we read on, we will see that this yeast caused Carlsberg many brewing problems and it was only when a combination of discoveries was made firstly by Louis Pasteur and then Emille Christian Hansen, that quality and consistency could finally be achieved in brewhouse performance.

In 1857 Pasteur discovered that yeast is the causative agent in brewing and confirmed that it creates alcoholic fermentation. He also proved that the yeast cells are the reason that Co2 is produced!

Pasteur’s work helped brewers understand why their workplace needs to be hygienic and he made it clear that they must store their yeast safely as well as holding some back in a yeast bank for safekeeping. *The COVID 19 Lock Down in 2020 has really underlined the importance of storing your yeast properly when not brewing. Many brewers have lost their yeast culture.

In 1883 Emille Christian Hansen  (Head of the Dept of Physiology at Carlsberg Brewery)  discovered that not just one but 2 forms of bacteria spoiled beer. This proved that yeast could exhibit different chemical reactions despite having the same colour, shape and size as other strains. By cleverly learning how to isolate an individual cell he could then propagate a pure individual yeast strain.

Hansen had finally managed to prove that the problematic yeast Carlsberg had sourced from the Spaten Brewery Munich in 1845 was a mix of 2 different types, the second of which (Carlsberg 2) was causing bitterness, slow fermentation and bad odour when on occasion that strain became dominant! This issue had gone on for close to 40 years.

This Wild Ale strain imposter yeast came from a nearby orchard and because Carlsberg always back- slopped the yeast, they often used the same contaminated batch which had been spoiled by this wild contaminant (It was probably brought in via brewers’ boots?)

Hansen could now re-pitch the positive Carlsberg type 1 yeast (bottom fermenting lager yeast strain) which became known as Saccharomyces Pastorianus. He would then bank and propagate it fresh each time and the beer would no longer spoil. This was now used in their future brewing.

Un-selfishly, Hansen sent this strain around the world so that other brewers could use it and this helped lager become more common in other countries.

As a side note, it was as late as 2011 when the source of the South American yeast strain was finally discovered in a Patagonian Orchard.  More recently, it has also been found in Tibet and Wisconsin but it is still not known how it got to Europe; maybe in an Oak cask as it likes to grow near trees??   The strain has never actually been found growing in Europe and it is not known how it was first used in European brewing back in the 1500’s.

Hybridisation of Lager Yeast

Over the year’s there have been 2 hybridisation occurrences’ in lager yeast history which is why we now have the 2 strains most in use. Interestingly, no one knows how this hybridization occurred!  Fortunately, when influenced by the chromosome makeup, the positive attributes become dominant. This process is called a transgression!

One strain is more positive for brewing than the other. You want the yeast to be good at low temperatures as seen with Hansens Carlsberg type 1 but also have a quicker fermentation performance as found at higher temps with the other (Frohberg yeast- known as type 2).

In modern lager brewing, The Frohberg has now largely replaced the Carlsberg strain, despite being more sensitive to low temperatures. It is more compatible with industrialised and modern brewing methods and ferments quicker.

The Frohberg creates higher alcohols, more esters and achieves greater fermentability of all of the sugars (unlike the type 1).  These attributes will suit some lager beer styles but if you want a traditional more neutral lager, then the Carlsberg Type 1 yeast brewed in the traditional way may still be the best option for you.

Carl Von Lind-ARS System

Following on from these advances in the raw materials, Carl Von Lind produced the Ammonia Refrigeration System in the 1880’s. This enabled the brewer to chill the beer.  Lind sold these systems so brewers could produce lager all the year round and not just in winter. Commercially, this was another major step forward.

Lager Malts

You have now chosen your yeast. Choosing the right lager malt to match with that yeast is also crucial when brewing a great beer.

Crisp authentic German Pilsen malt with its higher protein content works well when brewing with the European stepped mash and lautering systems (it can be mashed at a 63°C too), whereas a Europils or Extra Pale Malt (lager Malt) can be used at a single mash temperature as it is lower in protein and is better modified and offers a different option when using the Froberg strain.

German Pilsen Malt        Europils Malt        Extra Pale Malt

In the last few year’s some Craft Brewers have broken from tradition and use lager malts with an English Ale yeast. Brewdog Punk IPA is one such well-known example. These beers tend to be less bitter and more hoppy and seem to appeal more to the younger generation of drinkers whose palates have often not been exposed to stronger beer flavours.

In Bristol, Lost and Grounded Brewery is run by Alex Tronseco formerly of ‘Little Creatures’ Brewery. When they brewed Pale Ale it was fermented with an Ale strain of yeast, then fermented out, filtered bright, reinoculated with lager yeast, go into a conditioning room for 2 weeks and carbonation levels would be checked every day. This beer was all about how do very precise bottle conditioned beer on a large scale with every attention to detail. It didn’t actually go into bottles. This is a great example of thinking outside of the box and paying great attention to every detail.

One recent development in malt is a product called Clear Choice. This is available both as a standard pale malt but also as a lager malt, Clear Choice Extra Pale. It can be used for Blonde and Pale Ales,  East and West Coast IPA’s and all types of lagers.

Having had the proanthocyanidin gene bred out of the barley, the finished malt does not have any polyphenol precursors. These polyphenols can cause astringency in beer. Without these present, the beer made with Clear Choice is very smooth and drinkable and doesn’t develop a haze during shelf life.

 

The Brewing Lager Process

 

It may be helpful to remind ourselves of some of the basic principles when brewing a lager beer.

The distinct aims of the process are as follows:

  1. The reduction of the residual extract while maximising extract of the malt and wort. Note, we reduce the sugars in fermentation and convert the sugars to alcohol.
  2. The scrubbing of sulphides. i.e. the rotten eggs and struck match odours during primary ad secondary fermentation.
  3. The reduction of acetaldehyde. This is green apple flavour you can get and removing them is required.  Lagering will clear this up but it can be speeded up using ALTC (usually when using more modern processes). The lager yeast strain produces these green flavours (POF positive).
  4. The reduction of VDK. This is a group of compounds that create the butterscotch aroma and flavour taint. Not always considered bad in beer but generally avoided. Some lagers are famous for this flavour.
  5. A reduction of yeast cell concentration is required so as to produce bright beer. Longer lagering at sub-zero temperatures helps this. Some strains don’t like to sediment and take longer to do so (6 to 8 weeks in horizontal vessels).
  6. Clarity- least number of solids wanted. Again, longer lagering helps by reducing haze sensitive proteins in the beer.

Brewers Note – Another issue when brewing Lager is when Diacetyl is produced by the yeast. This is a chemical excreted from the yeast cell. At the end of fermentation, the diacetyl will be absorbed again as fermentable sugars become scarce, raising the fermentation temperature by a couple of degreed encourages the yeast to do this and is termed a diacetyl rest. *You can add an enzyme which will remove the diacetyl precursors, it’s called alpha acetolactate decarboxylase and can be purchased from brewing process aid suppliers

Lager Brewing Methods

When brewing a lager you have more than one brewing process to choose from.

The decoction brewing process is a way to conduct multi-step mashes. Usually, a 1/3 of the mash is transferred to another vessel where it is ‘conversion temperature boiled’ prior to being returned to the original mash tun. This raises the temp of the mash to the next step. It also breaks up any unconverted grist as well as producing a higher extract. This was traditionally required because the malt was not of very good quality. It also gets rid of unwanted proteins and allows a lower temperature mashing protein rest.

The decoction process starts mashing at a lower temperature that encourages protease enzymes to break down proteins ultimately giving a clearer beer. The decoction process creates darker colour lagers due to the portion of the mash that has been boiled.

Traditional Method

This method is still used but on a smaller scale of brewing i.e. not in industrial brewing. It is a slower process without modern brewing aides- it can take up to 3 months for the diacetyl to be reabsorbed and hit the correct spec!

In traditional lagering, the beer is primary fermented until most of the sugars have been metabolised by the yeast. You then transfer to a secondary vessel at this point ensuring that there is enough yeast for secondary fermentation.  Once the diacetyl rest is complete temperature is reduced and the yeast will continue to create alcohol and CO2, the gas will strip out unwanted volatiles and the yeast will also work away at the sulphur compounds over what can be a 3 month period in traditional lagering.

Having entered the second vessel for secondary fermentation. The CO2 bubble will be allowed to vent initially and take away some of the unwanted volatiles particularly hydrogen sulphide.

Following the above, the vessel is then sealed up and the wort is left to carbonate. Yeast, protein and unwanted tannins settle to the bottom over time (finings are not allowed under the German Beer Purity Law so all they have is time). The vessels are then closed and thus pressurised. This helps carbonate the beer.

To speed things up but still using a traditional method- you may want to use the Krausen process.

A Krausen addition of active fermenting beer from another vessel will provide additional extract and cell concentration into the beer that has already fermented out. This replaces the need to use additional sugars or other adjuncts and allows the diacetyl to come down faster i.e. 8-10 days rather than 20 days.

The term Krausen is what you call this added wort from another vessel.  This fermenting beer which is now being added back is very active and has reached its optimum point of fermentation. It is now added back to the more thoroughly fermented beer to condition the final product and naturally carbonate the end beer.

Modern Lagering Processes

In a modern lagering process, 5-10 % of fermenting beer added back to the brew provides extra cell concentration and helps reduce the diacetyl.  ALTC can also help speed this up.

In a warm conditioning lager method, the brewer can start at 7 or 8 degrees but it is allowed to rise to 13 rather than staying at the 8. At this point, you can take yeast away from the bottom to stop autolysis. As previously stated, the diacetyl gets removed quicker at the higher temps.

The downside of this quicker process is that potentially more esters and higher alcohols are found, and this may give you a more fruity and more alcoholic lager rather than a more neutral traditional beer, as when using the slower method.

To combat the flavour issue above you can ferment at a warmer temp and add pressure to the fermentation process allowing it to rise. This encourages more CO2 to form and prevents reactions that inhibit the forming of the esters and higher alcohols.

A Centrifuge is also something most modern breweries use nowadays to reduce yeast cell counts prior to either conditioning or filtration so settling tie is significantly reduced.

Some people argue that in the past the traditional lagering process was imposed on brewers because they had inferior raw materials. They state that you can now achieve the same quality of beer by modernising the process and this does not make their beers inferior in any way.

This is undoubtedly true for some beers, however, traditionalists will argue quite correctly that depending upon the beer you are trying to create, sometimes things shouldn’t always be rushed. The discerning brewer should be aware that although ‘time is money’ sometimes you must be patient to make the product the best it can be.

 

Final Words

 

Lager beer styles have evolved over many years. These styles have been heavily influenced by the developments in the raw materials as well as the chosen brewing method. Brewers have adapted to meet the changes in beer culture and peoples changing drinking preferences.

Understanding what your target marketplace is and the price points that you aim to achieve will also play a major role in deciding what products you make.

If you can satisfy your customer’s current and changing needs it will go a long way in helping you establish a reputation for quality and consistency as well as creating or maintaining an appealing brand.

We advise and support. We share our experience and expertise. We relish any opportunity to help with recipe creation or with solving issues around anything connected with brewing and beer.

Just give the sales team a shout: 01328 829391 or email sales@crispmalt.com

 
 
NigelGibbons
Posted by
Nigel Gibbons
on 08/08/20

Nigel is the Southern Sales Account Manager for Crisp Malt and lives in Suffolk.

Read More
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