Eureka, the following brew is one of the weirdest I have done so far. The recipe I am talking about is a Berliner Weisse recipe influenced by a traditional way to get it sour.
The story begins in Berlin, 1908. A man named Otto Francke patented a method to get a more consistent sourness in Berliner Weisse beers. The old way to sour a Berliner Weisse was to get the sourness from lactic acid producing bacteria during the fermentation. One disadvantages of this method was the inconsistent sourness. Otto Francke’s method changed that. Those of you who are familiar with German find the patent here. A short summary of his process: The process basically is about sour mashing. Otto Francke describes a method were you add lactic acid forming bacteria to your mash and let it ferment until the sourness is at an appropriate level. I assume that a kind of Lactobacillus strain was used for this task. Then you just heat up the whole mash and kill the bacteria. The level of sourness is now fixed. Then cool it down and let it ferment with a yeast.
The following information are from a thesis I got from a homebrewer in Germany. The thesis’ title in English is “About the flavor formation in Berliner wheat beer regarding acids and esters” and was written by F.J. Methner in 1987.
As already mentioned, there are at least two different strategies to sour a Berliner Weisse. The first one involves a pre-souring of the mash with the addition of Lactobacillus as described above. The wort is then pasteurized and fermented with a Saccharomyces strain and Brettanomyces bruxellensis is added at bottling. Yes, there were some Brettanomyces in the beer as well. This method is useful to get a consistent sourness. Another method to sour the beer is pitching Lactobacillus in addition to yeast for the fermentation. The important step here is to pitch a least a 1:1 ratio of the Lactobacillus: yeast cells. If there are more yeast cells than Lactobacillus at the beginning, the growth of the yeast can prevent the Lactobacillus and therefore lead to a lower sourness. Some of you familiar with Lactobacillus might know that some Lactobacillus strains are hop sensitive. One example of such a strain is the one available from Wyeast, Lactobacillus delbrueckii. This strain can therefore be used for sour mashing because there are no hops in the mash at this time. Problems could arise when you use this strain in the fermentation vessel for souring as there were hops in the wort or mash. Hop-insensitive strains such as L. brevis can be used for souring during the fermentation. But this strain is not available for homebrewers as far as I know.
Another interesting fact about sourness, the sourness in unboiled worts get higher than in boiled worts. The boiling seems to hinder the Lactobacillus in some way. It is therefore advisable to use a no-boil technique if the souring will be done in the fermenter.
The history and techniques of Berliner Weisse breweries in Berlin are not very well documented and research is still going on. This research and documentation seem very important to me since the Berliner Weisse breweries are very limited in Germany and the knowledge of Berliner Weisse brewing might get lost. Luckily there is a growing homebrewer community which helps to keep the knowledge of Berliner Weisse brewing. But there are some homebrewers in Germany as well who try to replicate the old Berliner Weisse that once existed. Luckily for me, all the old articles about Berliner Weisse are written in German and therefore have no problem understanding them.
So I planned on doing a sour mash as well but did not add any kind of Lactobacillus, just some additional malt. There should be some kind of Lactobacillus on the grains to get the mash to the appropriate sourness level. Lets first get through the recipe, details about the process are mentioned below. I used J. Zainasheff’s “Saures Biergesicht” recipe and tweaked it a bit.
|Recipe:||Traditionelle Berliner Weisse
|Numbers:||Volume [L]||18 (4.8 gal)|
|Terminal gravity||Not yet measured|
|Color||Around 6 EBC|
|Grains:||Pilsner Malt (4 EBC)||1.9 kg|
|Wheat Malt (4 EBC)||1.36 kg|
|Acidified malt (6 EBC)||0.2 kg (added after pre-mashing)|
|Hops:||Hallertauer (4% AA)||28 g Mash hops|
|Yeast:||#1338 European Ale|
|Water:||Burgdorf||Mash: 8.5 L (2.2 gal), sparge: 23 L (6.1 gal) @78°C (172°F)|
|Rest:||Pre-mash||Mash in @66°C (151°F), 60 min @ 66°C (151°F), cool down to 50°C (131°F) and add 0.2 kg of acidified malt. Leave mash for two days at around 38°C (100°F).|
|Second mash||Add hops and heat up to 78°C. Rest 15 min @ 78°C (172°F).|
|Fermentation:||Primary||7 days @ 20°C (68°F) in a plastic bucket|
|Maturation:||Carbonation (CO2 vol)||3.5 vol for bottles, 1.75 vol for keg
|Maturation time||3-4 months|
02/10/12: Brew day. Crushed the malts and mashed them in at 65°C. Then held the mash at this temperature for an hour. I then let the mash cool down to approximately 50°C (131°F) and added some crushed acidified malt. I then set my electrical kettle to 38°C (100°F) and let it sit.
Luckily, there is no smell coming with the pictures. The smell after 24 h was just incredible (Fig 1). There were some notes of fermented lemons, some sourness, and a very overpowering smell of vomit… The heat helped to distribute the smell evenly in my basement. And the mash was bubbling a bit (see white bubbles at the surface in Fig 1). Well, the smell was just too much! I was very close to dumb the whole thing to get rid of the smell in the basement. But I left the mash sour for another 24 h. By the way, there was some sourness detectable as I tasted the mash.
Then happened the first miracle. The next morning, the mash now rested for nearly 48 h, the vomit smell was gone, although still in my basement, but there was a very pleasant lemony smell. And the mash was even more sour than the day before. So I proceeded with my mission to replicate an original Berliner Weisse. I then added the hops directly into the mash and heated the whole thing up to 78°C (172°F) and left it there for 15 minutes. Then sparged the wort directly into the fermenter.
Another interesting thing here was the consistency of the mash. The mash was a kind of mushy as it can be seen in Fig 3. And this made the sparging a really hard job. I tried three different false bottoms I have for fly sparging. I then decided to go with a batch sparge. This did not improved the whole sparging a bit. So I went for a stir-and-flow technique. I first stirred up the whole mash and collected the runnings until it got stuck and repeated this process until the fermenter was full. I guess I do not have to mention that my efficiency of this batch was one of the lowest ever….
I then let the fermenter cool down outside and pitched a package of Wyeast’s European Ale yeast. Another thing that made me worry was the European Ale yeast. I know that this particular strain tends to a very long lag-phase before proceeding to the fermentation. But the fermenter stayed there for nearly two days without any signs of fermentation, kräusen or change in gravity. I already assumed that maybe the souring could have altered the mash in a way to make it unfermentable for the yeast. But then, another miracle, the fermentation took off after two days.
02/28/12: Bottling time. I added some table sugar for the appropriate carbonation levels and bottled half of the batch in a 9 L keg (2.4 gal) and the remaining liters into bottles. I then added some sediment from my BFM dregs, which include a Brettanomyces strain, to each bottle. No Bretts for the keg. The bottles and keg will now mature for nearly three to four months. I am really looking forward how this brew turns out. I hope that the tasting will be the third miracle…
By the way, I had a look at the mash with my microscope. And I could see a lot of different bacteria in there… Stay tuned for the tasting in late June.
07/19/2012: Uploaded the tasting notes of the share with Brettanomyces.