The changing De Dolle Oerbier, from Kris

David Frost Frostdr at AOL.COM
Thu Jun 16 10:02:53 CDT 2005


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/) 




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