Category Archives: Technique

19th Century Brewing Methods in Germany and Austria

Only the other day, I stumbled upon a book called “The Art of Brewing“, written by one David Booth, published in 1834. It has a whole section of brewing in foreign countries, discussing differences in brewing between Munich, Prague, Vienna, and other cities. The basis for this section is credited to two unnamed guys, can you guess who?

For the greater portion of ” the Brewing in Foreign Countries,” I am indebted to the manuscript and oral communications of two German Brewers (from Vienna and Munich), who have been, and now are, visiting the principal towns of Europe, for the laudable purpose of acquiring information concerning their business.

Yep, that sounds very much like Gregor Sedlmayr and Anton Dreher.

I also found another book, “Vollständige Braukunde” by Johann C. Leuchs,  that discusses the brewing methods of various German cities. In this article, I will try to summarize and discuss different German brewing techniques from the 19th century, and how they would be seen from a modern (home)brewer’s point of view.

Munich

For the mash, a mash tun made out of copper, with a false bottom, and a second, smaller copper, were used. The second copper was used for boiling the mash. The standard recipe is described to be 8 quarters of malt and 60 pounds of best Bavarian or Bohemian hops to produce 27 barrels of keeping beer. Calculating what the outcome of that would be, that would be a beer with about 6 to 7.5 % ABV, with probably 35 to 50 IBU. It does mention the Munich beer as keeping beer, meaning it was matured, or lagered, for a relatively long time.

The coarsely ground malt is doughed in, while the small copper is used to bring liquor to a boil. The boiling liquor is then added to the mash, to result in a 40 °C mash. Then a decoction is drawn, and brought to a boil. The author mentions a thick froth that is beaten down back into the mash. I assume this is hot break, and nowadays you would rather skim the scum instead of beating it back into the mash.

The first boil takes about an hour, where it gets a darker colour, until it is put back into the mash, to raise the temperature to 55 °C. Immediately, another decoction is drawn, but only boiled for 30 minutes, and then put back, with a resulting temperature of 67 °C. A third, thin decoction is then drawn, both taken from the top and taken from the tap (the mash tun has a false bottom, after all). Then it is boiled for 15 minutes, and put back, to reach a temperature of 75 °C. That whole procedure takes about 5 hours.

After that, the wort is drawn off. Hops are added while the first runnings are still drawn off, so this constitutes a first wort hopping. The overall boil lasts 2.5 to 3 hours. Fermentation is bottom-fermenting, as expected. What’s interesting is that after primary fermentation, the young beer is drawn into casks. A batch is spread out over lots of casks, though, so it takes about ten batches to properly fill all the casks. I presume this is to blend all the batches and to end up with a very consistent product over all casks even when the individual batches differ. Lagering period in the cellar is mentioned as lasting eight to ten months. That is indeed a keeping beer.

Beer brewed for the winter differs from this, as less hops are used, more wort is drawn off, and it’s boiled for a shorter period of time. There is very little maturation, and secondary fermentation for carbonation is initiated with Kräusen, and essentially happens in the publican’s cellar. This very much sounds like a running beer. Comparing with modern drinking habits, this is very counter-intuitive, as you’d expect the lighter beer to be brewed for the summer as a refresher, and the bigger beer to be made as a warming, boozy drink.

Augsburg

Apparently, the brewing methods in Augsburg were quite different from the rest of Bavaria. It starts with the malt: it is ground finely. The boiled hops of the previous batch are put on the false bottom prior to putting malt and then cold liquor over it. This is left for six hours. Boiling liquor is then added, and mashed for half an hour, and then more hot liquor is added, to bring it to 60 °C. This is then left for two hours. Sweet wort is then drawn off and put into the cooler. More hot liquor is added, and mashed for half an hour, with the resulting temperature being 67 °C. Then “all the goods” (I presume this means all hard matter) are put into the copper with hot liquor, and boiled for 45 minutes, then put back into the thin mash. The resulting mash is then at 86 °C. After some time, the cooled wort is put into the copper, the wort from the mash is also drawn off, hops are added, and the whole thing is boiled for two hours.

Fermentation is bottom-fermenting, and the beer is ready after about 2 months of maturation. Usually though, it is kept in large vats for a year to 1.5 years.

According to “Vollständige Braukunde”, beer brewed like that requires more cleanliness than the Munich approach, but has a higher yield and produces a milder beer.

Overall, a rather weird method in today’s standards. It seems like an infusion mash in the beginning, but with a final decoction, which would extract complex carbon hydrates, but leave the mash at temperatures where all amylases would have already been denatured, and no enzymes would be left to convert the starches into more simple sugars. Did the Augsburgers like their Blausud? (a Blausud is when a wort sample, mixed with an iodine solution, turns dark blue: it is an indicator that there’s still unconverted starches in the wort)

Prague

Prague’s brewing methods are described as similar to Munich, but with a fermentation “of the opposite kind”, which I assume means that in the 1830’s, Prague was still brewing with top-fermenting yeast.

Dough in starts at 46 to 50 °C, with an initial rest of nearly an hour. During that mash, more hot water is added to reach 59 to 63 °C. Then a decoction is drawn, brought to a brief boil, and then put back to get up to 67 to 68 °C. Then another rest of an hour follows. Wort is then run off, a Vorlauf if you will, with the express purpose to get rid of any grains underneath the false bottom. This wort is brought to a boil, and put back, to bring the temperature of the mash to about 84 °C. It is also emphasized that the grains must not be disturbed. Then a small portion of the wort drawn before is brought to a boil together with the hops, and the hops are taken out after 45 minutes. In total, the wort seems to get drawn off in batches and boiled, with the hops getting reused. A sparge is done, and the runnings are boiled with the hops from the previous boils.

Fermentation is done at 20 to 22 °C, so obviously top-fermenting. Maturation then happens in ice-cooled vaults for four to six weeks, and is served directly out of that cold environment. Yep, ice-cold beer.

Anyway, what we can see here is that the Munich style of mashing is a triple decoction, while Prague employed a double decoction.

Vienna

The crushed malt is doughed in with cold water, and mashed for two to four hours. Then cold wort is drawn off, and is brought to a boil together with liquor, boiling for 45 minutes. The froth on the top is skimmed off. It is then put back onto the malt, with a resulting temperature of 40 °C. Now this seems quite odd to me, as it would mean that a lot of the enzymes in the wort would be denatured quite early on.

Then something truly odd is done: wort is drawn off, and pumped back onto the mash. This is done for over an hour. A certain amount is kept in the copper, and again brought to a boil, but as soon as it starts boiling, it is added back to the rest of the mash, to increase temperature to 57 °C. Then more wort is drawn into the copper, again brought to a boil, boiled for 30 minutes, then put back into the mash. This is now left for 30 minutes at 72 °C. And then more wort is drawn off, again brought to a boil of 45 minutes, put back into the wort, and left for another hour at 82 °C.

Then wort is drawn off once more, and hops are added. When all the wort has been drawn off, the grains are loosened, and water of 56 °C is sprinkled onto it. The wort is boiled for 75 minutes, and some of it is put into the cooler. Then the second runnings are drawn into the copper, and boiled for another 90 minutes.

Then the wort is cooled to about 30 °C, and yeast is added. That’s a crazy pitching temperature. Fermentation is vigorous, and the young beer that is thrown out during the fermentation is collected and fermented in a separate vessel. This sound vaguely like the idea of a Burton Union, although with a separate vessel instead of recirculation. Shortly after fermentation has finished and the yeast has settled, casks of the young beer are sent out to the publicans. This all happens within 3 days.

So, in total, quite a strange process. Kinda like a decoction, except only thin decoctions are drawn. I wonder what prevented this from resulting in a Blausud, as well.

Berlin

This gets interesting now. Berliner Weisse. “The Art of Brewing” describes it as a beer made from 5 parts of wheat malt and 1 part of barley malt. That’s quite different from the 2:1 or 1:1 recipes that are listed in other old publications. “Vollständige Braukunde” mentions 20 parts of barley malt, 10 parts of wheat malt, and 2 parts of oat malt.

The finely ground malt is doughed in, and hot liquor is added to bring the temperature up 52 °C. This is left for an hour. Then wort is drawn off, and boiled with hops for 15 minutes. A thin decoction is drawn to interrupt the boil, and when this has reached 93 °C, it is put back into the mash, and left for 30 minutes, with a resulting temperature of 67 °C. Then another thin decoction is drawn, heated up to 96 °C, then both the mash and the decoction are put into the “tap-tun”, what sounds like a lautering vessel with a false bottom which is covered with straw (some sources say straw used in lautering was previously boiled in water). The resulting temperature in this tun is 75 °C. The wort is then drawn off, very slowly, though, and hot liquor is used for sparging. The overall lauter and sparge takes 7 hours, to produce a very clear wort. The wort is then put into the fermenting vessel, where yeast is added. Fermentation quickly begins, and the beer gets already shipped out to the publicans at this early stage.

In “Art of Brewing”, the author mentions that brewers thus have no yeast, and must buy it back from the publicans. To keep their yeast strains reasonably clean, they preferably buy from publicans that deal with other breweries than their own. The publicans also take care of bottling and storing the beer until it’s drinkable, which is usually after 14 days.

In total, this is quite the interesting process, as it does a kind of decoction, with the hop boil during the mash, and no further boil. Berliner Weisse is often described as a no-boil recipe, and people often ask themselves how the hops are added to it if there is no boil: directly during the mash. This way, the amount of isomerization of the alpha acids is easily to control, which is usually not the case if you added hops to a thicker mash that would undergo several decoctions.

Summary

In this article, I tried to summarize descriptions of different brewing techniques in German and Austrian cities at that time, in particular Munich, Augsburg, Prague, Vienna, and Berlin. It is interesting to see how the approaches completely differ, in particular the amount of decoctions that are drawn, what kind of decoctions are drawn, what is boiled for how long and in what order, and what temperatures are kept. With today’s knowledge and understanding of brewing and the microbiology behind it, it is fascinating to see what would be considered good practice nowadays, and what wouldn’t. The Munich triple decoction is a well-researched and well-documented method, as is the Prague double decoction. You would find descriptions of these in most modern brewing literature. The other methods, not so much. There, we find temperatures that would extract more tannins, or early thin decoctions that would denature lots of crucial enzymes early on in the brewing process. I seriously wonder how these brews went fine, and whether they produced Blausude.

DMS and Boil Time

After writing about the sources of DMS in beer a few days ago, I stumbled upon another quite interesting paper from 1978 that discusses the influence of boil time on the amount of DMS in beer, titled “Control of the Dimethylsulphide Content of Beer by Regulation of the Copper Boil”.

In this paper, the authors put together two different lager malt blends. LMB 1 was designed in such a way that it was kilned at 65 °C, so that it would only contain inactive DMS precursor (see the previous article about active and inactive DMS precursors). LMB 2 on the other hand for kilned at 70 °C and later at 90 °C, so that it would contain substantional amounts of active DMS precursor. With both malt blends, worts of OG 1.037 (9.25 °P) were produced using a single-step infusion mash at 65 °C. The worts were boiled for different times (from 15 minutes up to 2 hours). Each of the worts were split, and fermented with different yeast strains, NCYC 240 and NCYC 1324. The two different yeast strains differ in the amount of DMS they produce: NCYC 240 produces a high amount, while NCYC 1324 produces a low amount.

What was noticeable in the results from the different boil times alone is that there a strong correlation of boil time with decreased amounts of DMS and DMS precursor in the worts. Consistently, LMB 1 had lower amounts of DMS and DMS precursor compared to LMB 2.

When the authors looked at DMS levels after fermentation, the results were quite clear, as well: a longer boil not only brings down the amount of DMS and DMS precursor in the wort, it also consistently reduces the amount of DMS in the resulting beer.

Influence of Boil Time on DMS Levels in Wort and Beer

The paper concludes that the DMS content in beer can be controlled almost impossible from other influencing factors through the right boil length and temperature. There is one exception though: if the DMS comes from another source than DMS precursor, a longer boil doesn’t reduce besides the normal evaporation.

Just like I hypothesized in my previous article, I will mention this again: I think that the literature is quite clear in that the wort boil has a large influence on DMS levels in beer, just like the specific metabolism of the yeast strain has a large influence, and that in the Brülosophy exbeeriment, the experimenters were just “lucky” in getting the right malt with only low levels of DMS and active DMS precursors, and a yeast strain with only low DMS production.

Optimizing a Hefeweizen Mash for Esters and Phenols

A few days ago, I had the idea that I wanted to brew a classic Hefeweizen. In my few years of homebrewing, I had actualy only ever done a “proper” Hefeweizen once, and it was the “Almtaler Hefeweisse” kit from Hopfen&Malz. I wasn’t overly impressed by the specific beer, it seemed a bit too watery for my taste. But then, that may have been purely because it was my third beer that I ever brewed. After that, I brewed two more Hefeweizen, but both with a twist, i.e. a heavy late aroma hopping, followed by some dry-hopping with Nelson Sauvin. That beer was a success, but it’s definitely not your classic Hefeweizen.

A Bavarian Hefeweizen has some specific properties: it’s brewed from a mix of barley malt and wheat malt, with the wheat being at least 50% of the grist. Some commercial examples even contain as much as 70% wheat malt. The beer is cloudy, both from proteins from the wheat malt and yeast in suspension, and while pale, it’s usually a tad darker than your German pale lager, sometimes even going towards a reddish hue. Hop bitterness is very low, with no hop aroma. Alcohol-wise, the typical commercial examples usually have 4.8 to 5.5% ABV. The yeast strains used for that style are top-fermenting. Historically, Hefeweizen did not conform to the Bavarian Purity Law (Reinheitsgebot) because it contains wheat malt, while the Reinheitsgebot only allows barley malt. Special permits were instead issued to those who held the privilege to brew with wheat.

Because I wanted to brew a Hefeweizen on a rather short notice, I went to Bierlieb and got some ingredients. Their choice in ingredients is alright but not great, but definitely enough for quite a few German beer styles, your odd IPA or Belgian-style beer. Unfortunately, they only offer dry yeasts, so I had to get WB-06. Now, the thing is that I’ve heard quite a few bad things about WB-06, namely that it’s a rather bland yeast that produces only tiny amounts of the typical phenolic and ester notes of a proper Hefeweizen. My previous experience with dry yeasts in general and specifically Fermentis dry yeast has been rather good so far (S-04 is my standard for most British styles, US-05 is the Chico strain and so probably the standard for almost everyone’s American styles, and Saflager W-34/70 and S-23 have worked for me in the past, too), so I wanted to give them a try nevertheless.

Just to be sure that I would definitely get enough phenolic (clove) and ester (banana) notes in my Hefeweizen, I was looking for a way to optimize my wort production to provide the yeast with as much of the precursors as possible.

For the clove notes, that’s relatively easy. The phenolic clove notes in Hefeweizen come from the specific yeast strains metabolizing free ferulic acid to 4-vinyl guaiacol. Ferulic acid is in the malt itself, but it needs to be freed and available in the wort. That is usually done through a ferulic acid rest, at about 45 °C.

The banana notes on the other hand are esters, iso-amyl acetate and ethyl acetate, and their production by the yeast directly correlates to the amount of glucose in the wort. So obviously, I’d need to do a mash in a way to increase the amount of glucose. Fortunately, there is a pretty cool method for that, the Herrmann method, or Herrmann-Verfahren in German. It is named after Markus Herrmann who wrote his doctoral thesis at Weihenstephan about the formation and influence of flavouring substances in wheat beer about a decade ago (sorry, German only!).

The principle behind the Herrmann-Verfahren is relatively easy: malt contains a number of enzymes which manipulate starches and complex sugars at specific temperatures. The most important ones are alpha- and beta-amylase that do most of the work. But there is another enzyme, maltase, which can break down maltose into glucose. Unfortunately, maltase works at about 45 °C, and is quickly denatured at higher temperatures. So Herrmann designed a mash schedule that first produces a good amount of maltose through a straightforward Hochkurz infusion mash, with 60% of the grist. Then, a second mash with the remaining 40% of the grist and cold water is done, which is then added to the first mash, bringing it down to 45 °C. That way, the maltase enzymes from the second mash can munch on the maltose produced by the first mash and create more glucose. After that mash, a second dextrinization rest is conducted, followed by mash-out.

The whole process is illustrated here:

Herrmann-Verfahren

That way, you end up with a wort with a lot higher amount of glucose, eventually leading to more esters after fermentation with the right yeast strain. Coincidentally, the 45 °C of the maltase rest is the same temperature that is also necessary for the ferulic acid rest.

The recipe that I came up with for my Hefeweizen looks like this:

Grist:

  • 66.6% Pale Wheat malt
  • 18.5% Pilsner malt
  • 9.3% Munich malt (dark)
  • 5.6% CaraMunich II

Hops:

  • 0.5 g/l Hallertauer Tradition (7% AA) first wort hopping
  • 0.25 g/l Hallertauer Mittelfrüh (3% AA) @ 20 min

60 minute boil. 10 IBU. Mash as described above. WB-06 yeast. OG 13.25 °P. For carbonation, I’m using about 7.5% of the wort as Speise.

For fermentation itself, I’m chilling the wort down to about 17 °C, then I’ll pitch the yeast, and will let the temperature freely rise to ambient temperature (about 23 °C in my flat at the moment). Fermentis recommends for the WB-06 yeast to keep a temperature below 22 °C for clove flavors and above 23 °C for banana flavors. Given that my wort provides the yeast with enough glucose and ferulic acid to actually produce either flavors above the perception threshold, I should be fine with that fermentation schedule to achieve a hopefully balanced Hefeweizen with all the right aromas and flavors and none of the wrong ones.

As soon as the beer is finished, I’ll report back about the results.