The changing De Dolle Oerbier, from Kris

All, This is a very interesting article from Kris of De Dolle, explaining what happened (and is happening) with his Oerbier. Great reading! What Happened to Oerbier Since 2000? Kris Herteleer De Dolle Brouwers, Esen, Belgium At the end of that year the source of yeast had disappeared. The yeast strain used for Oerbier & Stille Nacht had come from Rodenbach brewery in Roeselare and they had decided to not supply any yeast any more due to reasons of organization and pratical reasons. Since decades there were some breweries Rodenbach had supplied yeast to: Trappists of Westvleteren who switched to Westmalle yeast after problems with sour beer. Felix in Oudenaarde who stopped brewing in 2001. Another famous brewery using Rodenbach's yeast was Liefmans. After the takeover by RIVA Rodenbach stopped the delivery of yeast to them a couple of years prior to 2000. The yeast of Rodenbach is very special and contains some different strains of bacteria other than Saccharomyces Cerevisea. They are Gram-positive and Gram-negative bacteria, some saye even Brettanomyces, which other breweries fear and do not like in their installations. Brewers say "clean" beer and "sour" beer do not match, so no lager beer brewer will use that strain for due to a potential acid-type beer in the same brewery. Supplying yeast to another brewery was also a token of comradry or at least collegiality knowing that small brewers did not have the installation nor the knowledge of treatment of yeast. There is also a kind of pride in delivering yeast to others. Because if a brewer does not like the beer he will not be interested in using the yeast. Americans will say: The ultimate honor to a beer is to copy it! {and this may be a reason, too, to keep the yeast for themselves!} The brewery Rodenbach wrote a letter in November 1999 saying that the yeast supply would stop on December 1, 1999. Knowing this was a weekend, this was short. We had heard rumours in that sense so we had some stock of yeast. By the time Palm took over Rodenbach I had such a feeling that the yeast supply would not be eternal, but it seems that Palm has nothing to do with it. If Rodenbach had been taken over by Heineken, for instance, would the yeast supply not have been ceased? Whatever , we were already happy to have had the opportunity of using their yeast for over 20 years and we therefore respected their decision. {Some American beerlovers were very angry and worte e-mails to Palm to "force" them to continue their yeast supply - but here in Europe , things don't work that way!} As I had done tests with oerbier wort with other strains, which were not convincing, I thought the best thing would be to reuse the yeast. For a single strain, that would be a good method, but with that complexity of the Rodenbach yeast soon some unexpected things happened: - The alcohol by volume of Oerbier increased from 7.5 % to 10.5%. For Stille Nacht , the density of which is even higher, it increased from 8% to about 12%. - With problems of refermentation as a result! - What also changed was the balance of acidity. The bacteria had disappeared. So we got a mutated strong pure yeast, and no more bacteria. There were other strange things happening as well. The refermentation of a batch of Stille Nacht seemed NOT to come to an end and the last three pallets of that beer had bursting bottles all over. Even in December with the colder temperature! As I could not longer stand the exploding bottles there was high time to find a solution! We poured the beer into wine barrels and bottled them as Stille Nacht Reserva 2000 after 12 months. The attenuation dropped to 1000 , even lower and the taste was really something exceptional. The empty barrels were then filled with Oerbier so we had Oerbier Special Reserva one year later. With the Reserva series we had so much time that sometimes it matured for over two years in the barrels, thinking that it could only get better by the passing of time. This maybe or may not be so. Up to now, though, we have not had one bad bottle of Reserva. Since 2000 we were looking up in beer books how the fermentation of old fashioned beers really went on, with the special strains such as Lactobacillus, Pediococcus, Brettanomyces and others. We had to know what they 'liked", what they did not "like", how they grew and what their behavior was when exposed to yeast. And that's exactly what is happening in wine. So we went through wine books and literature of Lactis bacteria as well as the history of English and Belgian beers in the 19th century. Together with a guy {probably sent from heaven!} wo works in microbiology of lactic bacteria used in bread, we installed a fermentor to grow yeast, yeast that we had cultured from kegs of De Dolle Stille Nacht ..that were returned from Finland. Some were not empty and the beer was delicious < we received 8 of those kegs in the USA in 2003> The kegs were very old , thus having the "old " balance of yeast and bacteria. To us this could not have been more fortuituous. We then started to reculture this yeast. The taste of Oerbier had changed. It was dryer, heavier and the balance of caramel malt was disturbed due to the disappearing of the maltery HUYS. So we adjusted that - and for the acid taste we went back to a tradition of old Flemish beers , which is to let beers getting sour with a controlled fermentation with lactic acid bacteria. The first four brews are already sold and marked for the USA by a white cap with "SPECBREW2005" on it. The first two pallets are less sour than the the second shipment to the USA marked "SPECBREW02". This is due to a larger amount of "sour" beer. We think the more soure beer should be our definite version, though some variations may occur. What are the reactions of our customers? They all taste the difference, most of them like the sour taste over the sweet one. {My mother-in law prefers it sweeet! She says that there will be some time needed to get accustomed to it}. Whatever, we must use the liberty of being small and follow our own taste of what beer should be. The alcohol by volume s now 9% which is still 1.5% stronger than the "old" oerbier. It is dryer, too, due to the stronger yeast. The acidity should be about the same. In terms of aging, no problems are foreseen. If you have other questions , the answer lies in your glass! Cheers, Kris Herteleer De Dolle Brouwers Look for the SPECBREW2005 on the shelves sometimes soon; it is now in, and is being distributed around Chicago. 10 cases. SPECBREW02 will be available shortly. And, honest, the Dulle Teve Special Reserva (calvados barrel aged) and Oerbier Special Reserva (Bordeaux barrel aged) should be available in early July!!! They are on the boat right now, and almost in port. David R. Frost B. United International Midwest Division Manager IL - IN - MI - WI - KS _www.bunitedint.com_ (http://www.bunitedint.com/)