Discovering sauergut, the great secret of German lagers, brewing a Helles

We have made it a habit in recent years to brew at least one lager beer a year. Every good homebrewer will know the difficulty of brewing a good lager at home and doing this is a very nice challenge for us, which also allows us to continue learning. Obviously, within lagers there are a multitude of styles, each with its own characteristics and peculiarities. For 2021 we decided to try it with a Munich Helles, a style that we love to drink. As I always do, I started a research work on the style to try to end up with the best possible result. And it was during this process, while looking for information about yeast strains suitable for this style, where almost by chance I discovered in a forum the word sauergut, totally unknown to me until that moment. I tried to look for more information about this term and the truth is that it is not abundant. Possibly this is due to the fact that most of the brewing literature and the more general sources of information that we usually handle come from the Anglo-Saxon culture, mainly from the USA, and in many cases these sources have been dragging myths, incomplete or outright false information about some styles. Of course there is information in German about sauergut, but my limited knowledge of the language prevents me from finding it useful. The fact is that little by little I got more information on the subject of what seems to be the best kept secret of German lagers.

Starter of the German lager X strain

And what on earth is sauergut, you may be wondering. Here I will try to explain it in a nutshell and give you a couple of facts so that you can see that it is something that is really established in the production of the acclaimed German lagers, especially in the Bavarian region. It all comes from the well-known German purity law, the Reinheitsgebot. According to this law, it is not permitted to acidify either the mash or the boil by adding lactic acid or any other chemical compound. For beers brewed under this law, there are two alternatives to reduce the pH of the mash and/or boil. The first is the use of acid malt (sauermalz in German), which many of you will know and possibly have used in your brewing. The second is to use an acid wort or sauergut. Although the original reason for using sauergut may have been to adhere to the aforementioned law, there are several studies that seem to demonstrate the benefits of its use over the addition of lactic acid. Among other things, sauergut allows almost twice as much zinc to be extracted from the malt in the mash, this element being an important nutrient for the yeast, as well as helping with the beer’s body and foam. In addition, many products of the metabolism of Lactobacillus (the main character in the production of sauergut) act as antioxidants in the beer. Aside from these less tangible benefits, sauergut is supposed to have a contribution to the final taste of the beer, giving a light yogurt-like, somewhat acidic touch that would be the particular hallmark of Helles and other Bavarian lagers. I discovered most of this information in a document on the German Brewing website entitled “On Brewing Bavarian Helles – Adapting to Inert Brewing”. That document is a guide to brewing the perfect Helles with a lot of steps to follow, some more complicated than others. I will comment later on which ones we followed since it was, among others, one of our reference sources for brewing.

As I was curious, I decided to look around to see if, indeed, the use of sauergut was something widespread at the level of professional breweries (especially in Bavaria) and not just something elevated to the altars by a handful of homebrewers. I first came across this brewery machinery page where you can see a reactor for sauergut brewing and maintenance. From what I have been able to read afterwards it also seems to be common in many German breweries, especially in the south. Later on, I received an email informing me that Doug Piper (I highly recommend his youtube channel, where he usually invites experts to talk about many topics and brewing styles) was going to talk in one of his videos about lager brewing, being one of his guests Tobias Zollo, brewmaster of Weihenstephan. I took the opportunity to ask about sauergut and Tobias himself confirmed that the use of sauergut is something common in the production of lagers (in the link you can listen to the complete answer). Curiosities of life, as I write this, I just received an email about an entry in Brulosophy where an exbeermiment is made with sauergut. Who would have thought it when a year ago I had not even heard of this word.

Calculations for the yeast starter

Making a small parenthesis on the subject of sauergut, let’s go with the rest of the ingredients we used. First we selected the yeast. After reading several opinions I came to the conclusion that there were several reliable alternatives that were not superior to each other. Among the handful of yeasts that were recommended as good choices for the style, I opted for German Lager X. This strain is from White Labs’ The Vault collection and is identified by the code WLP835. Strains from this collection are only available for short periods of time and when I saw it available it seemed like a good candidate for our Helles, as the White Labs website describes it as a strain that produces a malty, creamy profile with low sulfur and ester production. It is also taken for granted that this strain originates from the Andechs monastery in Bavaria (White Labs states that it is the strain from a “famous Bavarian monastery”).

For both the grain and the hops it was simpler, as this is not a style that allows too many frills with these ingredients and it is better to play it safe. In the case of the malt I decided on a Pilsner base plus a not too high percentage of Vienna Barke malt and a small touch of Carahell, all of them from Weyermann. As for the hops, as it could not be otherwise, Germanic hops to choose from those we had in stock. Halletauer Mittelfrueh for bitterness and Tettnager for aroma (the latter, although of German origin, grown near us in Olite by Queen Country).

The information, both for the part of the ingredients and the process, including of course the sauergut issue, I gathered from different sources. Mainly from the German Brewing page, as well as from their forum. I also found good notes on another blog, The Quest For Edelstoff, even if they were posts from a few years ago. In the end, all these sites in one way or another had for the most part a couple of original sources, the books by Kunze (Technology Brewing and Malting) and Narziss (Abriss der Bierbrauerei), two real bibles of beer in general, and German beer in particular.

One more note before describing the recipe and the brewing process we follow. The article I mentioned at the beginning of this post is a very complete guide that some of you may remember, as it was quite fashionable in homebrewing circles a few years ago. In it the authors, always based on contrasted information, offer a method for homebrewing with the minimum introduction of oxygen throughout the process. Some of you may remember it by the terms LODO brewing or Low-ox brewing. Among many other things, it is a method in which antioxidants (sodium metabisulfite, ascorbic acid,…) are used from the mash and great emphasis is placed on having closed circuits to avoid exposure to oxygen as much as possible. It is not easy to carry out at home, because it requires a series of adaptations of the equipment. Because of this, it was not our intention to follow this method to the letter, even though its authors claim that any deviation from it can spoil the spectacular final result. Even so, and anyway, we decided to apply several of the steps described in this method. Mostly because we brew beer because we find it fun and because, well, I don’t think everything is black and white, and we had probably never put so much care into brewing a lager (or rather any other beer), so the result could be better or worse, but not bad. You can read the whole article if you are curious and want to go further, because the level of detail is very high and all the whys and wherefores are very well explained.

Sauergut, ready to be used


3.00 Kg (6.61 lbs) (83.3%) Pilsner malt (Weyermann) (3.3 EBC)
0.50 Kg (1.10 lbs) (13.9%) Vienna Barke malt (Weyermann) (7.0 EBC)
0.10 Kg (0.22 lbs) (2.8%) of CaraHell malt (Weyermann) (25.6 EBC)
30.00 g (1.06 oz) Hallertauer Mittelfrueh (3.00% AA) pellets (first wort hopping, boiled 60 minutes, 12.0 IBUs)
10.00 g (0.35 oz) Queen Country (Olite) Tettnager (6.13% AA) in pellets (boiled 15 minutes, 6.3 IBUs)
White Labs German Lager X (WLP835).  Two-step starter, 1.5 liters each step, to obtain 21.2 million cells per mL of wort when inoculated (1.86 million cells x mL wort x degree plate).
Volume: 16.00 L      OG: 1.046     DF: 1.007      %Alc: 5.1%      IBUs: 18.4     Color: 7.5 EBC     BU/GU: 0.401              Efficiency: 65%
The water was taken the day before so that the chlorine could evaporate. On brewday we boiled it to eliminate as much oxygen as possible and added salts (and phosphoric acid) and sodium metabisulfite (600 mg) as an antioxidant. The mineral profile, without taking into account the contribution of sodium metabisulfite, was as follows:
Ca: 68 ppm; Mg: 3 ppm; Na: 7 ppm; SO4: 40 ppm; Cl: 45 ppm HCO3: 1 ppm.
Hochkurz mash: 62ºC (143.6ºF) 30 minutes, 72ºC (161.6ºF) 30 minutes and 76ºC (168.8ºF) 10 minutes. In the first minutes we added 225 mL of sauergut with the intention of lowering the pH of the mash 0.1, until a theoretical pH of 5.4.
60 minutes. 5 minutes before finishing the boil we added 400 mL of sauergut with the intention of lowering the pH of the boil 0.4, up to a theoretical 5.0.
In FastFerment placed inside the Ferminator. We inoculated the yeast at 7ºC (44.6ºF) and raised to 9ºC (48.2ºF) for 24 hours. We left it at 9ºC (48.2ºF) for 15 days, after which we lowered the temperature by 1ºC per day until reaching 5ºC (41ºF). At this temperature of 5ºC (41ºF) we left it for 15 more days. After this time, we lowered the fermenter to our basement and left it for another 3 weeks at 14ºC-15ºC (57.2ºF-59ºF) before bottling. We bottled 9 liters (2.38 gallons) of the Helles in a small corny, force carbonating with CO2. The rest, about 5 liters (1.32 gallons), we bottled to obtain about 2.5 volumes of CO2 carbonation.

As I am sure you would  have noticed, among the highlights of the process, and I will explain the reasons below, are the high inoculation rate, the use of sodium metabisulfite as an antioxidant, the addition of sauergut in the mashing and boiling, and the mashing and fermentation temperatures. The inoculation rate is much higher than we are used to seeing in most places. Normally for lager beers it is normal to read that an optimal inoculation rate is 1.5 million cells x mL wort x ºPlato. This would give for our recipe about 17.2 million cells per mL of wort. However, to perform the cold fermentation that we were going to follow (more or less approximately), to ensure a healthy fermentation it is necessary to raise this amount considerably more. It is recommended between 20-30 million cells per mL of wort and we went up to 21.2 million cells per mL of wort (or 1.85 million cells x mL of wort x ºPlato). For the starter calculation we used Yeast calculator. According to this calculator we had to make two steps of 1.5 L each, with magnetic stirring, to reach the target number of cells. This was considering of course the date of manufacture of our German Lager X vial of yeast. This high number of yeast cells is ideal for the fermentation that we were going to follow, where it is inoculated at around 6ºC (we did it at 7ºC) and it is raised afterwards to 8ºC-9ºC. At this temperature most of the fermentation takes place and then it is gradually lowered to 3ºC-5ºC (we did it at 5ºC).

In the case of mashing we used the process followed in the production of many German beers, called Hochkurz, which is a mixture of the words Hoch (high) and kurz (short). This is because it starts at a higher temperature than usual (between 62ºC-65ºC) and because the duration of the mash is shorter than other types of mashing in which there are more steps. We started at 62ºC, maintaining 30 minutes. In this step the activity of beta-amylase is favored. We then moved to 72ºC for another 30 minutes, favoring alpha-amylase activity, and finished with 10 minutes at 76ºC to inactivate the enzymes. In theory, this type of maceration favors a more complete conversion of sugars than a maceration with a single infusion temperature.

In the case of the water treatment, in addition to adding the salts and a little phosphoric acid (sorry, Reinheitsgebot) to seek a pH around 5.5 in the mash (before adding the sauergut), we also added 600 mg of sodium metabisulfite. This amount was following the German Brewing people’s recommended dosage of about 25-30 mg/L (in the case of no sparging) of sodium metabisulfite to act as an antioxidant. This slightly increases the sodium in the water, but only a few ppm which will not affect the taste.

Ferminator display during fermentation

Back to sauergut. There are different ways to prepare it (and keep it), but in our case it was going to be for a single use. The first thing to have ready is wort as sterile as possible. In our case, we used about 2 liters of spare wort form the one that we preprared for our test with the wild yeasts that we collected from fruits a couple of years ago. This wort, in anticipation of making this sauergut, we had prepared it with a recipe very similar to that of this Helles, as well as following the same type of mash (Hochkurz). The microorganism involved in the preparation of the sauergut is Lactobacillus amylolyticus. This type of Lactobacillus is naturally present in malt and malt is what we use for the preparation, although pure cultures of Lactobacillus can be used to inoculate the sauergut wort (L. Delbrueckii, L. Amylovorus, L. Acidophilus, etc). All of them must be homofermentative, that is to say, they must produce lactic acid as the main fermentation product. We boiled the 2 liters of leftover wort and transferred them to a pair of sanitized glass jars. One was left with 750 mL and the other with about 500 mL. We cooled the wort until it reached about 48ºC, at which point we added 15 g of uncrushed Weyermann Pilsner malt to the jar with the 750 mL of wort and 10 g of the same malt to the jar with the 500 mL, following the recommendation to add 20 g of malt per liter of wort in the above-mentioned article. We left the jars closed to avoid exposure to oxygen in a water bath maintaining the temperature at 48ºC (with a sous vide cooking apparatus that recirculates and maintains the water temperature), the ideal temperature for the fermentation of this type of Lactobacillus (and also a temperature too high for the growth of pathogenic bacteria). Although it is advisable to lower the pH to 4.5 before adding the malt, to avoid pathogen growth (with acid malt or sauergut brewed earlier to be purists), we did not do it this time. Theoretically, after 24-36 hours an acidity of 0.8% is reached and although this acidity then continues to increase, the speed of this acidification decreases very significantly, so this period is enough. We had it fermenting for 48 hours, after which we put it in the refrigerator until the day of brewing the Helles. I cautiously took a small sample from both jars and in the larger one the pH was at 3.58, while in the smaller one it had dropped to 3.48. Of course, I also tasted it and the flavor was very pleasant. Slightly acidic, but also with an important touch of raw cereal. For lack of a better description, I would say it was like a malt yogurt.

There are several strategies for using saugergut. Ours was to lower the pH of the mash to 5.4 with sauergut (from a theoretical value of 5.5) and to lower the pH of the boil, at the end of the boil, to 5.0, also with sauergut. Taking this 0.8% acidity as a theoretical value, 60 mL of sauergut would be needed for each kg of malt in the recipe to lower the mash pH by 0.1. In the case of boiling, this amount would be half, 30 mL per kg of malt in the recipe. In our case, after applying these calculations roughly, we added 225 mL at the beginning of the mash and 400 mL at 5 minutes to the end of the boil. A pH of 5.4 in the mash is a balanced value that favors both alpha- and beta-amylase and in theory can result in a fuller-bodied beer. This same value during boiling favors optimal formation of the hot break, and DMS evaporation is greater than at lower pHs. Finally, lowering the pH to 5.0 with sauergut at the end of the boil facilitates the formation of cold break.

Helles before packaging

On brewing day the process was as described in the recipe, with no major incidents to report. We started with the dechlorinated water after collecting it the night before, boiling it for a few minutes and adding calcium chloride and calcium sulfate, as well as a few mL of phosphoric acid to adjust the pH, and sodium metabisulfite as an antioxidant. Once the grain was added, taking care not to oxygenate too much, we did not stir as much as other times to avoid the introduction of oxygen into the mash. Once settled we added the 225 mL of sauergut to, in theory, lower the pH by 0.1. After finishing the Hochkurz mash described above we removed the grain and began heating the wort to boil. In a sample from the end of the mash the pH was at 5.48, somewhat higher than expected, although we had not measured the pH before adding the sauergut either. Before the boiling started we added 30 g of Hallertauer Mittelfrueh as first wort hopping, and then kept it for the whole boiling. With 15 minutes to go, we addded 10 g of Tettnager and with 5 minutes to go, we added another 400 mL of sauergut to leave the pH at 5.0, at least in theory. This value, in addition to favoring cold break, also seems to help beer stability, as Weihenstephan’s brewmaster commented in response to my question about the use of sauergut. After measuring a sample, our end-of-boil pH was 5.20, also somewhat higher than expected. It is possible that maybe our sauergut did not have enough acidity or another factor affected these values, but we were not far off either.

The biggest problem during the brewing process was when it came to cooling the wort. It is supposed to be cooled as soon as possible to about 5ºC-6ºC, but with the inmersion chiller and an ice bath we could not go below 16ºC. Not being ideal, I decided not to inoculate the yeast and put the fermenter in the Ferminator set at 5ºC, leaving it there overnight. The initial density was 1.047, practically the theoretical value (1.046). Early the next day the wort was already at 7ºC, so we inoculated the starter, removing as much wort as possible from the starter. At the end of that day we raised the temperature of the Ferminator to 8ºC, leaving it that way all day. On the second day we raised it one more degree, to 9ºC. At thius point there was already a significant krausen (we took a little look by opening the lid of the fermenter and it seems that the high inoculation rate worked well). We kept it at 9ºC for 15 more days, 17 from the brewing day. The density at this point was 1.009 (versus a theoretical DF of 1.007). From there, we lowered the temperature 1ºC per day until we reached 5ºC, leaving it at that temperature for 15 days. Here I decided to take the beer out of the Ferminator and leave it in the cellar for another 3 weeks at a temperature of about 14ºC-15ºC. Almost two months after brew day we bottled 9 liters in a small 9.5 liter corny keg and the rest, about 5 liters, we bottled with sugar for carbonation around 2.5 volumes of CO2. The final density was 1.008, for 5.1% alcohol. The smell was very interesting and the taste was very good, quite clean and with a good malt presence. In a future post we will tell you how it turned out and if we noticed the addition of sauergut. Be that as it may, with this brew I can say that I have learned more than with any other, and for that alone it was worth it.

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1 Response to Discovering sauergut, the great secret of German lagers, brewing a Helles

  1. Pingback: Mannermaisia oluita Irlannista: Wicklow Wolf Arcadia ja Heff Bezos | Olutkoira

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