Lambic Digest #0868

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Date: Wed, 12 Jun 1996 11:43:27 -0600 
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Subject: Lambic Digest #868 (June 12, 1996) 

 

 

 
Lambic Digest #868                             Wed 12 June 1996 

 

 
        Forum on Lambic Beers (and other Belgian beer styles) 
                Mike Sharp, Digest Coordinator 

 

 
Contents: 
  AHA Talk part 6 (Jim Liddil) 
  AHA Talk Part 7 (Jim Liddil) 
  AHA Talk Part 8 (Jim Liddil) 

 

 
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---------------------------------------------------------------------- 

 
Date: Tue, 11 Jun 1996 7:43:34 -0700 (MST) 
From: Jim Liddil <JLIDDIL at AZCC.Arizona.EDU> 
Subject: AHA Talk part 6 

 
Oak Barrels 

 
The vessel used by traditional lambic brewers to ferment 
their beer in is the  European oak barrel.  Oak barrels are 
considered the ultimate vessel by many  homebrewers making 
lambic-style beers.  The oak barrels used by lambic brewers  
are generally used wine barrels of European origin.  They 
have had the majority of  tannins and other wood related 
compounds leached out of them by wine  fermentation. The 
traditional lambic brewer has various barrels, many of which 
are  quite old, with the size usually being 600 liters or 
so. 

 
The advantage of an oak cask over other vessels is that it 
provides a  microenvironment where the various yeast and 
bacteria can grow.  This is due to the  porous nature of the 
wood, which provides nooks and crannies for the  
microorganisms to inhabit.(20)  The permeability allows the 
slow diffusion of air into  the fermenting wort and this may 
further aid the growth of the microorganisms as  well as 
flavor development.  After a cask has been used for a number 
of batches it  will become, one hopes, infected with the 
right microflora further aiding in the  production of a more 
authentic product. 

 
It also seems that as a cask is used for many years the 
various flavors from previous  batches of beer as well as 
those from the yeast and bacteria build up in the wood  and 
further add to the complex flavor profile of each successive 
fermentation.  It is  felt by some that even old oak adds a 
certain minor astringent note to the lambic  from the 
remaining tannins that are slowly leached from the wood. 

 
The homebrewer has to consider a number of things before 
obtaining an oak barrel.   One has to consider the size, the 
type of oak (American or European), where to put it  and 
whether to get a new or used one.  First let s look at the 
type of oak barrel to  buy.  Regardless of whether you 
choose to buy a barrel made of American or  European oak, 
make sure it is a wine barrel that is uncoated.  Do not buy 
a whiskey  barrel as they are charred on the inside and 
really only meant for making whiskey.   Do you really want 
that burnt wood flavor in your lambic-style beer?  Your best 
bet is  to buy the barrel from a cooperage rather than 
through a homebrew supplier.  That  way you can get 
specifically what you want and also save some money.   

 
It is generally felt that European oak is superior to 
American oak.  This is based on  the fact that American oak 
trees and European oak trees are different species (21).   
This leads to them having different profiles of the various 
compounds that are  extracted during the fermentation 
process.  The grain structure and thus porosity of  the two 
species is also different.  It is felt that American oak is 
too  oaky  as  compared to European oak.  There is some 
truth to this, but in the past few years  things have 
changed (22).  Part of the problem with too much  oakiness  
in  American barrels has to do with the way the wood is 
dried and aged.  European  cooperages have traditionally 
aged their wood for at least 2 years before it is used to  
make barrels.  During this drying and aging process many of 
the  oaky  compounds  are volatilized from the wood.   

 
American cooperages on the other hand quite often oven dry 
the wood in a matter of  days and then used it to make 
barrels.  This leads to an over abundance of oak  character 
left in the wood.  Some cooperages still use this method for 
their less  expensive barrels.  Others have started to 
follow European practice and are aging  their wood for 
extended periods.  Unfortunately most of the cooperages in 
America  that age their oak don t make barrels in any size 
less than 200 L.  If you are looking  for a barrel of 5-15 
gallons you will probably have to do some calling around to 
see if  you can find a barrel in stock made of aged wood.  
Small barrels are not kept in  stock by many cooperages 
because demand is relatively small.  Also it is no surprise  
that many of the cooperages are in California due to the 
large wine industry there.   

 
Another factor to consider is the cost of European vs. 
American oak.  The majority of  European oak barrels come 
out of France and currently the franc is pretty weak.  An  
investigation of prices for barrels revealed that most 
European barrels cost almost  twice as much as equivalent 
American barrels.  If cost is no object and you are in the  
market for a new wine barrel then of course go ahead and buy 
a barrel of European  origin. 

 
If you choose to buy an American barrel make sure it is a 
wine barrel.  Again try to  find one that is made from air 
dried wood, preferably of a year old or more.  Also get  the 
barrel with a medium  toast   This is a process where the 
insides of the staves of  the barrels have been lightly 
browned but not charred as with a whiskey barrel.  This  is 
done to barrels that are destined for red wine production 
since it further reduces  the tannins and oakiness of the 
wood.  Since a barrel is a major investment ask to  speak to 
a cooper about how to prepare the barrel.  Ask what will be 
done if the  barrel fails to hold water when you fill it.  
Will they exchange it for a new one?  Most  cooperages have 
people on staff willing to discuss how to prepare a barrel 
and are  willing to provide an exchange for a leaky barrel.  
If you buy a barrel from reputable  cooperage leaking should 
not be a problem anyway.  Barrels come in a range of  sizes 
starting at around 3 gallons and going up to 50 gallons or 
more.  Typically  though, European barrels do not come in 
sizes smaller than 25 liters.   

 
If you choose to buy a barrel remember that it is going to 
have liquid in it for a year  or more.  It will need to be 
in an environment that does not freeze or exceed 80 F  (27 
C) as these are the general extremes in temperature 
encountered in Belgium.  A  barrel full of beer is going to 
weigh 8.3 lb./gallon of liquid plus the weight of the  
barrel.  If you choose to buy a 10 gallon or larger cask 
think about the logistics of  filling and storing it ahead 
of time. Due to the weight you may need a hoist or a few  
strong friends to lift it.  Also be sure you have the 
brewing capacity to fill the barrel.   It is not a good idea 
to partially fill the barrel. This may lead to drying of the 
staves  and leakage.   

 
The price of a barrel does not increase linearly with size.  
Typically a 10 gallon one  is only about $20-30 more than a 
5 gallon size.  This holds true whether you buy  American or 
European.  Most of the cooperages selling American oak 
barrels  designate the size by the gallon capacity whereas 
the dealers of European barrels  designate size by the 
liter.  This is just another point to consider when 
investigating a  purchase.   

 
Another source of barrels is previously used ones.  Many 
wineries in the US use 200  or 225 Liter European barrels 
and you can pick them up for around $50 used.  This  
requires you live near a winery and that you have the 
brewing capacity to fill it and  the storage space.  Many 
wineries only use the barrels for 3-4 years before selling  
them.  The trend toward using barrels for a shorter time has 
come about due to the  decreasing use of sulfites and the 
increased risk of Brettanomyces infection this can  bring 
about.  Thus you can get a barrel in really good shape for 
an excellent price.   Unfortunately finding used barrels of 
smaller sizes is not so easy.  Wineries and  cooperages that 
deal in used barrels usually do not have anything other than 
200- 225L sizes.  It seems wineries do use the smaller sizes 
to keep wine in that is used  to make up the ullage in the 
big casks.  But they use these small casks until they are  
ready to be used as fire wood.  So if you find someone with 
a used 5 or 10 gallon  barrel for sale that is in good shape 
consider yourself lucky.  Another source of used  barrels 
maybe home wine makers who might be getting rid of a used 
cask.  Finally  note there is a company that is 
reconditioning the larger used barrels and downsizing  them 
to 30 gallons.  (See Barrel Supplier List) 

 
Some people warn that any beer made in an American Oak 
barrel will taste like an  oak branch.  They also feel that 
it will take numerous batches of beer to extract all  the 
oakiness from the wood.  You will have to make a personal 
decision regarding  American vs. European Oak.  Regardless 
of what you buy you want the majority of  the oak character 
removed from it prior to using it.  The quality of a 
European barrel  is not necessarily twice as good as an 
American one either.  Any barrel, if well cared  for will 
last for decades.  To reduce the chances of oak beer you 
will want to buy  either a used barrel or a new one that is 
made from air dried wood with a medium  toast interior.   

 
Regardless of the source any new barrel is going to have a 
certain degree of oak  character that will be imparted to 
the beer.  This is particularly true in the making of  
lambic-style beer, where the wort stays in the barrel for a 
long period of time.  During  this time period a great 
amount of chemical compounds can be extracted out of the  
wood.  So it is suggested that you chemically strip the 
barrel.  When you first get the  barrel you will need to 
swell it with water to make it liquid tight.  It is at this 
stage  when you find out if the barrel is of good quality or 
not.  At first you will need to top  up the barrel daily as 
the wood swells and absorbs water.  It may leak some at 
first,  but should stop after 3-5 days.  Once a good quality 
barrel has been swelled it  should show no further signs of 
leakage unless damaged. 

 
To maximize the amount of oak compounds leached out of the 
wood change the  water in the barrel every three days for 
two weeks.  This also ensures no mold will  grow in it.  If 
you live in an area that has high humidity you may want to 
add  metabisulfite from the start at the rate of 200 PPM.  
After two weeks of soaking start  the chemical stripping 
process to really remove the oakiness.  This is done by  
adding sodium carbonate (washing soda) to the cask at the 
rate of 1/2 ounce/gallon  and letting it soak for a week.  
Then drain the cask, rinse it well and repeat the  process.  
To maximize the extraction repeat this process for 4 to 6 
weeks.  At this  point the water in the barrel should be 
clear when drained as compared to the tan  liquid when you 
start the process.  Next neutralize any residual sodium 
carbonate by  adding citric acid to the cask full of water 
to drop the pH to 3 and let it set for a few  days.  Then 
rinse it well and fill it with metabisulfite solution to 
inhibit mold growth  until you can brew and fill it with 
wort. 

 
Following this stripping procedure can help you reduce the 
chances of having  multiple batches of oaky beer.  If you 
get the right barrel and are careful to strip it  thoroughly 
there is no reason not to use a barrel of American origin.  
Besides, even  a European barrel will need to be stripped to 
some extent to reduce the oakiness that  is present in any 
new unused barrel. 

 
So now you have a barrel and it has been full of beer for a 
year or two and you want  to bottle the beer.  What do you 
do with the barrel once it is empty?  First you should  
never leave a barrel that has held liquid empty for any 
period of time as it will dry out  and shrink.  This may 
lead to leakage that will not ever stop.  Sometimes a leak 
can  be stopped by hammering the steel bands of the barrel 
closer to the center.  You will  be better off if this can 
be avoided.   

 
Since lambic-style beer takes so long to ferment and age, 
when you bottle is not  very critical.  You will be better 
off if you coordinate when you will empty the cask for  
bottling to a time when you can brew a new batch to fill the 
cask up again  immediately.  For example, the day you are 
brewing you can transfer the contents of  the barrel to a 
carboy(s) or other holding vessel leaving as much of the 
lees behind  as possible.  This will allow the beer a chance 
to settle until you are ready to bottle  anyway.  Then you 
can rinse the cask out with water and have it all ready to 
fill when  your wort is cooled.  This way there is no chance 
of the cask drying out and all the  microflora in the wood 
remain intact and happy.  If you must empty the barrel and  
cannot fill it immediately, rinse it with water and burn a 
sulfur candle in it and bung it  up tightly or fill it with 
metabisulfite solution.  Then when you have time to brew 
rinse  the cask well and fill it with wort. 

 
A barrel is a major investment and can be ruined if it gets 
moldy on the inside.  Thus  it is important to keep it 
filled up close to the top at all times.  This requires 
making  up the ullage at regular intervals depending on the 
dryness of where you live.  Also  as previously stated, when 
there is not beer in the cask keep it filled with  
metabisulfite solution.  Do not use bleach or iodophor as 
these would likely taint the  wood and kill all microflora 
present in the wood.   

 
The outside of the cask also requires regular attention.  
Again depending on where  you live the outer surface may 
develop mold over time.  You can spray the outside  of the 
cask with metabisulfite at regular intervals or whenever you 
see signs of mold  developing.  Some people use a 200 PPM 
bleach solution or 25 PPM iodophor.   These are probably OK 
to use as long as you do not saturate the wood with them.   
Others favor applying linseed oil to the outside of the 
cask.  The important thing is to  keep an eye on your 
barrels and treat mold and mildew infections when they  
develop.  This is all part of taking care of a barrel so 
that it will last for years.  It  would be a shame to have a 
cask well infected with Brettanomyces and  Pediococcus, 
ruined by mold. 

 

 
Oak Chips The contribution of the oak from a cask to the 
flavor of lambic is considered to be  minimal based on 
discussion with various individuals.  This is due to the 
fact that the  casks used are many times' decades old and 
were previously used for wine  fermentation.  Thus they have 
had the vast majority of tannins and phenolic  compounds 
leached out of them.  This said, it is still felt by some 
that the oak may  add some astringent quality to the lambic.  
If you feel that using oak may help  contribute complexity 
to the flavor of your lambic-style ale but do not want to 
deal  with a cask then you might want to consider using oak 
chips.  The are usually  available from homebrew shops or 
can be specially ordered.  It is suggested you use  toasted 
chips and that you soak them in a couple of changes of 
boiling water prior to  using them in the fermenter.  This 
will help remove the majority of the oak flavor  compounds 
from the wood.  You do not want beer that tastes like an 
oaky  Chardonnay.  Preliminary experiments indicate that 
after the chips have been  exposed to lambic-style ale the 
microorganism do invade the pores of the wood.   This was 
shown by taking the  infected  chips and washing them 
thoroughly with  sterile water.  The chips were then added 
to sterile wort from which Brettanomyces  and Pediococcus 
could then be recovered.  Researchers have shown that the  
microorganisms do indeed invade the pores of the wood (20).  
This is another area  wide open for experimentation. 

 
Bottling 

 
There is some variation in the way lambic, particularly 
gueuze, is bottled in Belgium  today.  Many of the brewers 
artificially carbonate, sweeten and pasteurize their beer  
to produce a more consistent less aggressive product that 
has a wider market  appeal.  In their beers the ratio of old 
to young beer or top fermented ale is typically  not very 
high.  The traditional brewers who make true refermented 
gueuze also use  various ratios of young to old lambic, but 
never normal top fermented beer.  The  method used by some 
involves the mixing of 50% two year old or older lambic with  
50% young lambic of 6 to 12 months of age.(13)  The beer is 
then bottled and  allowed to referment in the bottle for up 
to two years prior to release.  The method  favored by the 
Boon Brewery involves mixing 95% 2 year old lambic with 5% 
2-3  month old lambic and then bottling.  Frank Boon prefers 
this method due to the fact  that the 50/50 method can lead 
to ropy and or hazy bottles that do not develop a  
consistent character.  This is not Brewing Art in his 
opinion.   

 
Those of us in the US rarely have the luxury of being able 
to mix young and old  lambic.  So we have to make due with 
what works for our other brewing, that is using  priming 
sugar of some sort.  Of course if you do happen to have 
lambic-type ales of  various ages fermenting then of course 
go ahead and try to blend and bottle them  and see what you 
end up with.  Gueuze, being refermented in the bottle is 
many  times fairly highly carbonated, though there are 
examples that are nearly flat.  This is  part of the  Art  
and variability of the process. 

 
The problem with conditioning a beer in the bottle that has 
been fermenting so long  is that the number of viable carbon 
dioxide producing organism may be very low.  If  this is the 
case the beer may not become carbonated or only very 
lightly.  To combat  this problem you may want to prepare a 
fresh starter of Brettanomyces and/or  Saccharomyces at the 
time of bottling.  Then you want to prime with enough sugar 
to  end up with a fairly carbonated product.(2.5-3 volumes 
CO2)  Using a cup of corn  sugar can lead to adequate 
carbonation after as little as two months.  Other times  
there may be little carbonation after two years.  It would 
not seem to be a good idea  to add Saccharomyces at the time 
of bottling since they do not survive through the  lambic 
fermentation process.(12)  But those of us who have looked 
at what is in the  sediment of a recent Boon lambic have 
discovered that the only yeast generally  recoverable is 
indeed non-cyloheximide resistant yeast, most likely 
Saccharomyces.   Boon fines his old lambic before adding the 
young beer and in the early stage of the  ferment 
Saccharomyces is the dominant strain.  Limited testing 
indicates that this  yeast is indeed acid and alcohol 
tolerant. 

 
As with other aspects of this type of brewing, and with all 
homebrewing for that  matter, you have a great deal of 
latitude with bottling.  There are some things you  should 
keep in mind though when you are considering transferring 
your beer from  the fermentation vessel to bottles or other 
serving containers.  If the beer has been  fermenting for a 
year or longer the viability of the microorganisms in the 
beer may  be low and/or may be predominantly bacteria and 
not yeast.  If the viability of the  yeast is low and you 
choose to bottle the beer unblended with corn sugar then you  
may get little carbonation of the product.  If the 
predominant microorganisms present  are bacteria then they 
will utilize the sugar before any yeast and again you will 
get  little carbonation.  This is because the predominant 
bacteria in an older lambic-style  ale will most likely be 
of the homofermentative variety.(i.e. Pediococcus)  As  
described elsewhere, homofermentative bacteria do not 
produce gas as they  metabolize sugars.  Again you can 
possibly combat this problem by adding a fresh  starter of 
Brettanomyces along with a heterofermentative lactobaccilus. 
Apparently  there is a symbiosis between the yeast and 
bacteria that can aid in carbonation.  

 
You can choose to put your beer into bottles using other 
traditional techniques or  standard homebrewer methods.  You 
can also put your beer into kegs or other  containers that 
can be artificially carbonated, such as PET bottles using a  
Carbonater (TM) or TAP-CAP(TM).  You can also naturally 
condition your beer in a  keg and then serve it using CO2. 
The choice is up to you and you need to make  some decisions 
regarding what you ultimately want to achieve. 

 
Let s start with bottling, as it is still the traditional 
technique used by lambic brewers  in Belgium.  As stated 
before, as long as beer is fermenting in a vessel it is 
called  lambic. When it is bottled and refermented it 
becomes gueuze or one of the fruit  flavored derivatives.  
Of course we are not making real lambic, gueuze, Framboise  
or Kriek since our product does not meet all of the 
qualifications of an authentic  product.  To make a 
gueuze-like product the beer needs to be put into bottles 
and  refermented in a fashion not unlike standard 
homebrewing practice.   

 
If the beer is fairly old and has a thick pellicle of yeast 
on the top and a large layer of  yeast at the bottom of the 
vessel then you may want to consider racking the beer.   
Transfer the beer to another vessel, being careful to leave 
as much of the top and  bottom layers behind as possible.  
Then you can let this beer settle for a week or so  prior to 
bottling.  This technique allows you to minimize the amount 
of sludge carried  over into the bottles.  Of course you do 
not want a completely yeast free product as  it will then 
fail to referment in the bottle after priming.  As stated 
before one can run  into problems with lack of viable 
microorganisms in the beer.  In a best case  scenario the 
beer will still have adequate numbers of viable yeast even 
after settling.   In that case you simply transfer the beer 
once again to a bottling vessel and add  corn sugar (enough 
to reach 2.5- 3 volumes CO2). Bottle it and wait for it to  
condition.  Sounds simple, but unfortunately lambic-style 
beer making does not  always lend itself to simplicity, 
especially when you are trying to make a product with  good 
flavor complexity. 

 
------------------------------ 

 
Date: Tue, 11 Jun 1996 7:47:16 -0700 (MST) 
From: Jim Liddil <JLIDDIL at AZCC.Arizona.EDU> 
Subject: AHA Talk Part 7 

 
Blending 

 
Let s look at how the lambic makers in Belgium make 
traditional gueuze.  At the  Cantillon Brewery they blend 
70%  old  lambic and 30%  young  lambic.   Old   lambic is 
beer that has fermented at least two years and  young  
lambic is beer that  has fermented about 6 months.  The 
bottled beer is then allowed to referment in the  bottle for 
6-7 months or more until it is deemed ready.  After 
refermentation the beer  has reached an attenuation of 90% 
or more (15). 

 
At the Boon Brewery things are done a little bit 
differently.  Frank Boon has a slightly  different view of 
the world and wants a more consistent product that has good  
keeping qualities and a good appearance.  To this end Boon 
gueuze is made by  blending  old  beer that has fermented at 
least two years with very young beer that  has only been 
fermenting a few weeks.  They are blended at a ratio of 95:5  
respectively.  Boon also clarifies the old beer prior to 
blending.  This gives a bottled  product that is reasonably 
clear and does not develop ropiness.  The blending  
technique requires that you use your hydrometer to determine 
the extract in the old  and young beer and then mix them 
accordingly. (7,9).  Then you bottle the mixture  and hope 
for the best.  This technique requires that you have more 
than one batch of  lambic-style beer going at a time. 

 
Using the fresh starter approach can still cause problems if 
there is a large amount  of bacteria in the beer at 
bottling.  They may consume the sugar before the yeast  and 
thus little or no carbonation will develop.  To alleviate 
this problem one can  remove the bacteria by filtering the 
beer prior to bottling at the 0.2 micron level.   Then all 
you need to do is add fresh yeast and sugar.  Alternatively 
you can prime  with DME since it contains more than glucose, 
the only sugar that the bacteria can  utilize.  The bacteria 
will consume the glucose and then the Brettanomyces will  
consume the remaining sugars and dextrins and carbonation 
will develop.  Or at  least that is how it should work in 
theory.   

 
One can use the blending approach, but instead of using 
young lambic you can use  a standard ale that has been very 
lightly hopped, if at all.  You can measure the  gravity of 
the standard ale and the lambic-style ale and then blend in 
the right ratio  to give you enough extract to achieve 
carbonation.  As with the other techniques you  can add a 
fresh starter of Brettanomyces to aid in adequate 
carbonation.   

 
Homebrewers have at their disposal another source of 
dextrins to use for priming in  the form of maltodextrin 
powder.  This powder contains little glucose and maltose  
and will eventually be hydrolyzed into fermentable sugars by 
the Brettanomyces  cellular enzymes.  Standard priming rates 
can be used for maltodextrin since it will  ultimately 
become primarily fermentable sugars given enough time.   

 
One could use any combination of the above when bottling.  
There is a great deal of  experimentation left to be done in 
this area of lambic-style ale brewing.  Keep in  mind that 
lambic microorganisms grow slowly and it may take months or 
even years  for the product to reach equilibrium.  Lambic, 
unlike most other beers, continues to  change for the better 
with age, quite often becoming more complex and less harsh.   
The key to lambic ale brewing is to be patient and go ahead 
and start other lambic  ales and allow them to age.  In a 
few years you may be rewarded with a very nice  complex 
product and then again you might not.  The important thing 
to keep in mind  is that as a lambic-style ale referments in 
the bottle chemical reactions are occurring  that lead to 
various flavor changes.  These reactions occur at a fairly 
slow rate, since  many of them are catalyzed by enzymes from 
Brettanomyces.  Remember  Brettanomyces grow slowly and 
never reach very high concentrations in the  fermenting beer 
or in the bottle.  This is one of the reasons why it takes 
lambic ales  so long to ferment and for proper flavor 
development to occur in the bottle.  Be  patient! 

 
Brewers in Belgium have a distinct advantage when it comes 
to bottling their beer  and achieving the right flavor.  A 
typical lambic brewery has many casks with lambic  in them 
from which the brewer can choose.  This allows the brewer to 
achieve the  right flavor complexity and balance in his 
product.  If a barrel contains lambic that is  too hard it 
can be blended with softer lambic to achieve the right 
flavor.  The typical  homebrewer does not have this option 
available to him or her.  Usually a brewer has  one five 
gallon batch going which is then bottled.  Depending on many 
factors the  single batch may end up being too hard or too 
soft in character.  As a brewer you  have a number of 
options.  You can brew lambic-style beer on a regular basis 
and  thus over time (years !) have enough lambic on hand to 
allow you to blend.  The  other approach is to ferment a 5 
or 10 gallon batch in one gallon bottles and hope  the 
resulting beers all differ in character to some extent. 

 
Quite often none of these approaches is practical for a 
homebrewer.  But I will  remind you that making lambic-style 
beers is not about being practical or making  beer in the 
easiest manner.  One must make a decision based on what he 
wants to  achieve when making this type of beer and how many 
sacrifices one is willing to  make in order to achieve a 
product that has any of the flavor and complexity of the  
real thing.  The choice is up to you. 

 
Sanitation 

 
Homebrewers and brewers in general are concerned with 
sanitation and about  bringing wild yeast and bacteria into 
their breweries whether by accident or  deliberately.  Such 
concerns apply more to the professional rather than amateur  
brewer.  The homebrewer can easily take all his equipment 
apart and thoroughly  clean and sanitize it.  The 
professional does not have this luxury.  Carboys, buckets,  
hoses and other equipment can all be exposed to the 
appropriate cleaners and  sanitizers to eliminate any wild 
yeast and bacteria.  This writer brews all his beers  using 
HDPE and PC containers and has used the same containers to 
brew lambic- style as well as other beers for the last 3 or 
so years.  Cross contamination has not  been a problem at 
all. It is important to clean and sanitize all equipment 
thoroughly  before and after each use.  Make sure all 
equipment is free from any dirt and grime  and use an 
appropriate sanitizer.  After a container has had beer in it 
for a year it is  important to clean it well.  Automatic 
dishwashing detergent works well for this task  since it 
contains TSP as well as sodium hypochlorite.  Thus it does a 
preliminary job  of sanitizing the container.  You can then 
soak the container overnight  in your  favorite sanitizer 
and then rinse it out the next day.  By following good 
cleaning and  sanitation practices you should not have to 
worry about cross contamination.  If you  are concerned 
about contamination you may want to have a dedicated set of  
equipment for lambic-style beer brewing.  For a more 
thorough discussion of  cleaning and sanitation you may want 
to consult some additional references (18,19). 

 
Enteric Bacteria Characteristics and Growth (new section) 

 
During the first month of the spontaneous fermentation of 
lambic beer the dominate  bacteria consists of 
enterobacteria.  These bacteria grow very rapidly and effect 
the  growth of subsequent yeast and bacteria.  They also 
effect the flavor of the beer via  the various metabolic 
byproducts they produce.   

 
The enterobacteria that have been found to be present in 
lambic beer include  Enterobacter cloacea, Klebsiella 
pneumoniae, Escherichia coli, Hafnia alvei,  Enterobacter 
aerogenes and Citrobacter freundii.  These are gram-negative 
straight  rods which are motile with the exception of 
Klebsiella.  There can also be non-motile  variants of the 
other species.  They all are able to ferment glucose with 
some  producing gas while others do not.  Most of them grow 
quite well in the presence of  air and are also able to 
ferment lactose.  These bacteria follow either a butanediol  
fermentation pathway or a mixed acid pathway.  This leads to 
large amounts of lactic  (~1500 ppm), acetic (~600 ppm) and 
succinic (~275 ppm) acids along with 2,3  butanediol (~2000 
ppm) being formed in the first month of the fermentation 
(10, 23).   They can reach levels of 1 X 108 cells /ml 
during the first 30-40 days of the  fermentation.  After 
this period the decrease in pH and the increase in alcohol  
caused by yeasts of the Saccharomyces species causes them to 
die off.   

 
The various by products from the growth of the 
enterobacteria can lead to various  flavors described as 
celery-like, parsnip-like, mushroom-like, smoky or mouldy 
(10).   These flavors are not removed by the fermentation 
process.  The various acid  products described previously 
also have an impact on the beer flavor contributing to  the 
acidic taste of the final product.  In fact the majority of 
acetic acid found in  lambic beer originates in the first 
month and is the byproduct of enterobacterial  growth.   

 
Typically enteric bacteria are considered pathogenic 
(disease-causing) in humans.   They are often considered the 
cause of various forms of food poisoning.  This is  indeed 
the case, with Salmonella being cause of the vast majority 
of cases (24).   The enteric bacteria found in lambic are 
generally not considered pathogenic in  people other than 
those who have immune systems that have been compromised in  
some way (i.e AIDS or immunosuppresive chemotherapy).   

 
Research has shown that the kitchens of many peoples homes 
harbor more enteric  bacteria than their bathrooms. (24)  
These bacteria include all those found in lambic  along with 
Salmonella.  Meats, vegetables and kitchen sponges or wash 
cloths have  all been found to be highly contaminated, with 
the later having particularly high  bacterial counts.  This 
makes the kitchen an ideal environment for allowing the  
introduction of enteric bacteria into ones wort. 

 
Discussions among homebrewers about making lambic-style 
beers have also  avoided the subject of enteric bacteria.  
This has been due to the fear of food  poisoning and the 
associated side effects.  Again research would indicate that  
anyone who brews in their kitchen does indeed end up with 
some amount of enteric  bacteria in there beer.  The growth 
of the brewing yeast and the subsequent  reduction in pH and 
increase in alcohol kill the bacteria off before they can 
cause off  flavors or other problems in the majority of 
cases.   

 
It can be argued that without enteric bacterial growth and 
the subsequent depletion  of glucose and production of 
metabolic byproducts lambic would probably not have  the 
depth of flavor and complexity that it does.  Because 
homebrewers have been   afraid  of enteric bacteria they are 
missing an integral part of the production  process.  
Studies indicate that the enteric bacteria have a profound 
effect on the  subsequent growth and flavor development in 
real lambic.  In order to achieve the  same flavor profile 
it would seem important to have this initial growth of these  
bacteria.   

 
In order to allow the wort to become infected with enteric 
bacteria a reasonable  approach would be to leave the 
fermenter open near a kitchen sink for an hour or  two after 
the wort has cooled.  Then the brewer should wait an 
additional 24 hours  before adding any yeast.  This will 
allow the enteric bacteria to gain a foothold and  begin to 
grow and multiply to a level that allows them to produce a 
significant  amount of metabolic byproducts and deplete the 
glucose.  After 24 hours the  addition of a small amount of 
yeast will ultimately lead to the enteric bacteria being  
killed off.  Again because the yeast will produce alcohol 
and lower the pH of the wort  to a level at which the 
bacteria can no longer survive. 

 

 
------------------------------ 

 
Date: Tue, 11 Jun 1996 7:50:38 -0700 (MST) 
From: Jim Liddil <JLIDDIL at AZCC.Arizona.EDU> 
Subject: AHA Talk Part 8 

 
Brettanomyces Characteristics and Growth  

 
Brettanomyces is considered one of the major yeasts 
responsible for the flavor  characteristics of lambic.  
Typically the species most homebrewers use are either  
Brettanomyces bruxellensis or lambicus.  These yeast have 
cell shapes that are  usually ellipsoidal and can also be 
cylindrical or elongated.  They frequently form  chains as 
they grow also.  These cells  quite often form 
pseudomycelium and grow  as filamentous branched cells. (25, 
26)  This gives the cells the ability to float and  form a 
pellicle on the beer.   

 
Brettanomyces have the ability to form acetic acid from 
glucose under aerobic  conditions.  Thus when they grow on 
calcium carbonate agar there is a visible zone  of clearing 
around the colonies.  They demonstrate a negative Pasteur 
effect.  That  is they demonstrate a higher production of 
alcohol under aerobic conditions as  opposed Saccharomyces 
which show decreased alcohol production under aerobic  
conditions (27).  Brettanomyces also have cellular 
dextrinases that allow them to  utilize dextrose polymers 
larger than the typical trisaccharides that can be utilized 
by  Saccharomyces.  A culture of Brettanomyces has a 
characteristic acetic, earthy,  horsey aroma.  These yeast 
grow much more slowly than do Saccharomyces  brewing 
strains.  Also they are resistant to cycloheximide unlike 
most normal  brewing yeasts.  Brewers classify Brettanomyces 
as  wild  yeast and typically do all  they can to avoid 
them.  In normal brewing these yeasts will lead to various 
off  flavors described as phenolic, smoky and goaty.  In 
lambic beer these are desired  characteristics. 

 
Another aspect of Brettanomyces is their ability to 
enzymatically catalyze the  formation of esters from the 
corresponding alcohol and acid.  Thus ethyl alcohol and  
acetic acid can be combined to from ethyl acetate and lactic 
acid and ethanol can be  combined to form ethyl lactate.  
These are two of the primary esters found in lambic  beer 
(28, 29). 

 
Pediococcus Characteristics and Growth 

 
Of the lactic acid bacteria found after about three months 
of fermentation,  Pediococcus damnosus is the dominant one 
in traditional lambic brewing.  It is a  spherical, 
tetrad-forming, gram positive bacteria.  Pediococcus is 
described as a  homofermentative bacteria because it 
ferments glucose to lactic acid without the  production of 
carbon dioxide.  As the Pediococcus grows the concentration 
of lactic  acid increases and can reach levels of 5000 PPM 
or more in the lambic.  This  increase in acid is a slow and 
progressive occurrence over a number of months.   
Pediococcus is a very fastidious organism, meaning it grows 
slowly and has complex  nutritional requirements.  Because 
of this fact and the environmental conditions, the  
concentration of cells is never very high, being only 1 X 
106 cells/ml or less.  Of  course this is in reference to 
spontaneously fermented lambic; cells numbers may be  higher 
in an artificially inoculated wort.  The lactic acid as well 
as diacetyl and  acetoin that the Pediococcus produce 
contributes to the complex flavor and aroma  of lambic, with 
the acid making the largest contribution.  The levels of 
vicinal  diketones (diacetyl and acetoin) have been found to 
be at or below taste threshold  levels.(13) 

 
Culturing and Maintaining Lambic Organisms 

 
To brew lambic-style beer it is advantageous to know the 
basics of yeast culturing.  It  is a further help to know 
how to culture the various organisms specifically involved 
in  lambic fermentation.  For the purposes of this article 
the discussion will focus on the  culturing of what are 
considered by many to be the primary players in the  
fermentation process.  Besides Saccharomyces these include 
species of  Brettanomyces yeast and Pediococcus damnosus 
bacteria.   

 
Any type of Saccharomyces can be used for the primary 
fermentation of a lambic- style beer, since it will 
contribute little if anything to the overall flavor profile 
of the  finished product.  One can find any number of 
articles and books on how to culture  these yeast and 
maintain them in the home brewery. (25, 26, 30, 31, 32) 

 
It is the other organisms involved which are more difficult 
to culture and maintain  without some experience and 
knowledge of how they grow.  The yeast of the  Brettanomyces 
species bruxellensis and lambicus and the bacteria 
Pediococcus  damnosus are microorganisms that require very 
specialized nutrients and  environmental conditions.  It 
should be noted that unless you are going to brew  
lambic-style beers more than once or twice a year you may be 
better off buying new  cultures each time rather than trying 
to maintain them in a home environment.  If  you do feel the 
need to maintain the cultures at home then you should become 
very  familiar with the culturing of normal brewing yeast 
first.   

 
Both Brettanomyces and Pediococcus produce acids as  normal 
metabolic by- products and because of this they need to be 
maintained on media which can help  neutralize it.  
Otherwise, the acid will lead to a large drop in pH and the 
organisms  will die.  The most readily available food grade 
acid neutralizing agent is calcium  carbonate (CaCO3), also 
called precipitated chalk.  A concentration of 2% (2 g/100  
ml) in the growth media or agar will provide adequate 
buffering capacity.  Calcium  carbonate is essentially 
insoluble though and this can present problems if it is used 
in  making wort agar.  To prevent the CaCO3 from falling out 
of solution before the agar  solidifies, cool the wort-agar 
solution to 113-122 F (45-50 C), with constant swirling,  
prior to pouring it into the tubes or dishes.  When CaCO3 is 
used in liquid media one  can gently swirl the media with 
the culture growing in it once or twice a day to help  
prevent any stratification of the acid in the solution and 
aid the neutralization of it  with the CaCO3.  As the lambic 
organisms grow in the liquid media the acid  produced will 
react with the CaCO3 causing it to be solubilized over time.  
Even  when a culture reaches maximum confluence there may 
still be some CaCO3  unneutralized, but this is not anything 
to worry about as the acid produced by the  growth in the 
main wort will dissolve it in time. 

 
Brettanomyces Culturing 

 
The Brettanomyces yeast can be grown on wort agar which 
incorporates 2% CaCO3  as noted previously.  The wort itself 
should be of a gravity of approximately 1.040  and 
preferably made from an all grain wort due to the possible 
lack of nutrients in  malt extract (5,6).  Due to the 
fastidious nature and acid production by  Brettanomyces they 
need to be transferred to new slant more often than do  
Saccharomyces.  It is recommended they be transferred to new 
slants at least every  2 months.  Longer intervals between 
transfers may lead to cultures which are no  longer viable. 

 
Because of this frequent manipulation there is a greater 
chance the yeasts  themselves may become contaminated with 
other yeast, mold or bacteria.  Thus  your sterile culture 
technique needs to be very good and you need to pay 
attention to  details.  If your culture does become 
contaminated you can prepare a dilute  suspension of the 
yeast and streak it out on a petri dish which has wort agar 
with 2%  CaCO3 and also incorporates 10 ug/ml cycloheximide. 
(Appropriate cautions  inserted)  As the colonies grow watch 
for a zone of clearing around the individual  colonies.  
Agar prepared with calcium carbonate will be opaque and 
white in color  and as the Brettanomyces grow the acid they 
produce will dissolve the calcium  carbonate and create the 
zone of clearing.  Generally only non-Saccharomyces  yeast 
will grow on media with cycloheximide in it and those that 
do grow and have  zones of clearing around them are likely 
to be Brettanomyces.  You can then pick  the colonies off 
and re-culture them on cycloheximide-free media.  This is by 
no  means a definite technique for the isolation and 
characterization of Brettanomyces.   Yeast such as Kloeckera 
are also acid producers that will grow on cycloheximide  
agar.  If you have doubts at all then you may be better off 
buying new cultures  and/or locating a microbiologist who 
will work for homebrew.  The only absolute way  to 
characterize a culture is through extensive fermentation, 
assimilation and  morphological testing, don t believe it if 
someone tells you otherwise. 

 
Pediococcus Culturing 

 
Pediococcus is more difficult to grow and maintain than is 
Brettanomyces due to its  more complex nutritional and 
environmental requirements.  Pediococcus grows best  in 
liquid rather than solid media and this increases the 
chances for unseen  contamination.  Unless you have access 
to a 1000X power microscope and have  culturing experience, 
it is recommended that you do not try to maintain this 
bacteria  at home for any length of time.  MRS (deMan, 
Rogosa and Sharpe) broth is the  preferred media for growing 
and maintaining Pediococcus over long periods.  It is a  
defined media that is rather expensive but provides the 
necessary nutrients and  buffers for optimal growth over 
extended periods.  Prepare the media as indicated  on the 
package.  Sometimes bacteria can lose their hop resistance 
if grown in  unhopped media for extended periods.  Thus if 
you are going to try to keep cultures  going over a period 
of time it is suggested you add iso-alpha acids to the media  
using some type of hop extract.  Use of whole or pellet hops 
leads to particulate  matter which causes the media to 
become cloudy and less than ideal for visual  monitoring of 
growth.  A suggested level is in the 15-25 IBU range.  A 
minimum  suggested passage interval is every month.  Allow 
the culture to grow for a week at  room temperature and then 
it can be stored at 4 C.  Another method for storing  
Pediococcus is the use of stab cultures. MRS media is 
prepared using 1.5 % agar  and put into tubes.  The tubes of 
solidified media are inoculated by using a needle or  
inoculation loop to stab the bacteria into it.  The 
bacterium is allowed to grow at  room temperature for a week 
or so until signs of growth can be seen.  Then the  tubes 
can be stored at 4 C.  Whether you use liquid or stab 
cultures you need to  keep the tube caps screwed down tight 
to limit air diffusion into the cultures and  prevent 
desiccation.  There is no need to worry about pressure 
buildup since  Pediococccus are not gas producers.  The same 
caveats apply to bacteria culturing  as for lambic yeasts: 
you need the proper equipment and good technique.  

 
If you are going to get serious about culturing 
microorganisms used for lambic-style  beers then you might 
consider buying or building a laminar flow hood of some 
type.   This will allow you to work in a nearly sterile 
environment.  Fungi Perfecti is one of  several companies 
that sell them or you can build your own. (33) 

 
Starters 

 
Whether you choose to culture your own lambic microorganisms 
or buy them, you  will need to propagate them prior to 
adding them to the wort.  A wort of specific  gravity 1.040 
with 2% CaCO3  will work just fine for this purpose.  You 
may also want  to add some hops, to achieve a range of 15-25 
IBU.  You should follow a scale up  procedure for these 
microorganisms so as to reduce the risk of other organisms 
over  growing the cultures.  With lambic cultures one does 
not have to make as large a  starter as that used for normal 
beer.  Start with a volume of 1/4 ounce (~5 ml) and  allow 
the culture to reach confluence.  When it has, add the 
contents to a volume of  4 ounces (~100 ml) and allow it to 
again reach confluence.  At this point you can  pitch or 
scale up one more time to a volume of 1 pint (~450 ml).  
Such procedures  have also been outlined elsewhere (30, 31, 
32).  Be aware that Brettanomyces is a  very slow grower as 
compared to other yeast and generally does not develop a 
large  kraeusen head either.  The starter should develop a 
typical Brettanomyces aroma  due to the various fermentation 
byproducts.  You should notice a distinctive acid  aroma 
along with aromas often described as horsey or mousey.  The 
starter will also  develop an acidic, mousey, earthy taste 
if the yeast is indeed Brettanomyces. As the  yeast grows 
the acid produced will cause the CaCO3 to dissolve and the 
fine white  precipitate from it will mostly disappear. 

 
Due to the additional vitamin requirements of Pediococcus 
you may want to add  10% apple or tomato juice to the wort 
starter.  Another alternative is to use 0.5%  dried brewers 
yeast.  Yeast extract is even better due to its purity and 
solubility, but  it is expensive.  Wort from a previous 
brewing session with 0.5% yeast extract added  works very 
well.  This gives a nice clear media in which one can 
monitor the growth  of the bacteria more easily.  As the 
bacterium reaches confluence a clear zone will  develop at 
the top of the liquid and the rest of the liquid will be 
very cloudy due to  the large amount of bacteria.   

 
For other beers you want to pitch a large volume of yeast to 
ensure a rapid  fermentation and decrease the risk of 
contamination by wild yeast and bacteria.   Well, 
lambic-style beers require you to throw caution to the wind.  
Large starters of  normal ale yeast, Brettanomyces and 
Pediococcus are not required.  If the yeast and  bacteria 
are healthy there is no reason they should not grow in the 
wort using the  small volumes as described previously.  
Remember this beer will be in a vessel for a  year or more 
and the bacteria and yeast have plenty of time to grow.  
Also as the  acid producing strains grow they will kill off 
any other organisms due to the lower  than normal pH, 
increase in alcohol and reduction in sugars that are 
fermentable by  other organisms.  If you feel the need to 
use larger starters to put yourself at ease  then by all 
means go ahead.  Just remember the beer will still take a 
year or so to  develop the proper character. 

 

 
------------------------------ 

 

 

 
End of Lambic Digest 
************************ 
-------
Lambic Digest #0868

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