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3rd Annual Big QC Day
(To view the 2010 page (4th Annual Big QC
Day) click here)
* 4th Annual QC Dates Released: We will be
shipping out the kits Feb. 4th and 5th 2010 and they must be
postmarked by Feb. 17.
* Give your feedback here
* 2009 results are posted
below -
bacteria dropped for the 3rd year in a row
* Click here for regional
results on selected tests
* Find a sample beer analysis report here
* Other results: 2008, 2007
What is Big QC Day?
For three years in a row, participating breweries have submitted
two beers each (or more, depending on how many tests they ordered)
for a variety of tests described below. The tests, which have
involved about 10 percent of craft breweries, have provided a
picture of the state of craft beer in general. Each year, the
percentage of contaminated beer has dropped, among other results.
As in the past tests, Big QC Day 2009 involved
the following tests, among others:
microbiological analysis
overall,
microbiological analysis by test, aerobic bacteria,
alcohol,
anaerobic bacteria, calories,
color,
density, IBUs,
real extract, total
VDK, wild yeast, pH,
apparent attenuation,
real
attenuation. Some of these tests were also broken down by
region. Links to these regional results can be found here,
or follow the links under the applicable tests.
Below are the 2009 Results
Below: Microbiological testing overall
 Regional
micro
overall
Microbiological testing overall: The above
graphic shows the
percentage of beers tested that had any
level of bacteria contamination. The tests showed
that 89 percent of the beers were bacteria-free, up from 84 percent
in the 2nd Annual Big QC Day and 80 percent in
the 1st Annual Big QC Day. For those breweries that did have
bacteria in their beer, White Labs suggests increasing quality
control efforts and testing.
Below: Microbiological testing overall - by
test
Regional
micro
overall by test
Below: Aerobic bacteria
Aerobic bacteria: This test was used with Wallersteins
Differential, or WLD, medium. This medium is used to check for
bacteria and some non Saccharommyces-type wild yeast. Most aerobic
bacteria will grow on these plates, and some anaerobic bacteria also
display growth. Bacterial contamination seen on these plates is
termed “wort bacteria” because they are most often associated with
wort contamination, usually causing most of their damage before the
onset of fermentation. As for the numbers, the same applies to
aerobic bacteria as in the paragraph above about lactic acid
bacteria, or anaerobic bacteria. Sometimes aerobic bacteria are
already dead by the time this test is performed, after fermentation
and packaging, but they could have contributed to off flavors.
Positive aerobic bacteria results can be from sample collection,
follow up tests are usually done to confirm contamination of
product.
Below: Alcohol
Regional
alcohol
results
Alcohol: We use an Anton Paar Density Meter DMA 4500 and Alcolyzer Plus. Results
are reported as percent vol/vol.
Below:
Lactic acid bacteria (or anaerobic bacteria)
Anaerobic bacteria:
This test was conducted using Hsu’s Lactobacillus medium, or
HLP. This medium is used to look for the presence of Lactobacillus
and Pediococcus. These bacteria are anaerobic, heat sensitive
bacteria. They are called “beer spoilers” because they are most
often associated with post wort production contamination. The
industry standard is less than 10 colony forming units (CFUs) per
ml. If it is over 10, the beer may develop flavor problems. However,
any CFU’s found from this test should cause concern and an
evaluation of your brewing and packaging process.
Below:
Calories
Regional
Calorie
test results
Calories:
Calories are calculated from the data and reported as kcal per 12 oz
serving of beer.
Below: Color
Color: A spectrophotometer is used to measure the
absorbance of a sample at a certain wavelength. The sample is
separated from solids, and the absorbance at a wavelength 430 nm is
measured. The number will show how light or dark the beer is. It can
vary between 2 Lovibond to 100 Lovibond. A stout obviously would be
high because it is dark.
Below: Density
Density: This is the specific gravity of the beer. Values
depend on styles. We use an Anton Parr Density Meter DMA 4500 for
this test, which gives us a high degree of accuracy.
Below: IBUs
Regional
IBU testing
results
IBUs: The IBU scale provides a measure of the hop derived
bitterness of beer. The higher number, the greater the bitterness.
Porters range between 20 to 40, for instance, while India Pale Ales
are 40 or higher.
The American Society of Brewing Chemists International Method,
bitterness units, is used. Iso-alpha acids are chemically extracted
using the organic solvent iso-octane. The ultraviolet light
absorbance is measured in a precision spectrophotometer, and the
results are reported in bitterness units.
Below: Real Extract
Real Extract: This test shows
you the sugars that are left in beer, usually non-fermentable
carbohydrates. Real extract involves accounting for the alcohol,
which we were able to do since we measured alcohol in the samples.
Alcohol has less density than water, so if you measure straight
density it does not account for the subtraction of alcohol. Results
are reported in degrees Plato.
Below: Total VDK (including
diacetyl)
Total VDK (including diacetyl): Results
reported in ppb.
VDK is measured on our Perkin Elmer Clarus 500 Gas Chromatograph and
Headspace Sampler. VDK (vicinal diketones) consists of diacetyl and
2,3-Pentanedione. The test includes heating the sample, which drives
diacetyl precurses to diacetyl. The lower the number the better, in
most cases. If you are under 100 ppb you are doing well. The numbers
vary depending on the yeast strain and fermentation procedure. If
the number is high, perhaps in the 200 range, the brewery may not be
performing an adequate diacetyl rest. Or again, it could be the
yeast strain. Examples of strains with higher VDKs are the British
strains and some lagers. Very high VDK levels can be an indication
of contamination. Additional tests can be performed that can
separate diacetyl and 2,3-Pentanedione levels.
Below: Wild yeast
Wild yeast: This test was
conducted using Lin’s Cupric Sulfate, or LCSM. This medium uses
cupric sulfate to inhibit the growth of brewers yeast. This medium
ensures no contamination of non-Saccharomyces wild yeast. Again, the
information concerning numbers is the same for wild yeast as the
contaminants listed above under anaerobic and aerobic bacteria. In
other words, under 10 meets the industry standard, 10 or more
indicates problems. Typical off flavors produced by wild yeast
would be phenolic and band-aid flavors.
Below: pH
pH: The pH of beer is an important indicator of quality
and consistency. A high pH can result in flavor problems and make
the beer more prone to contamination. We use a pH probe to measure
the pH of each beer. Typical pH values are 4.2 to 4.6.
Below: Apparent
Attenuation
Apparent attenuation: Attenuation is expressed as a
percentage of the difference between the original and final
gravities of the beer. Apparent attenuation is before accounting for
ethanol, which has less density than water. Attenuation will vary
by beer and yeast strain, typical ranges for apparent attenuation
are 65-90%. We include apparent attenuation and apparent extract in
your results so you can compare in house brewery data.
Below: Real attenuation
Real attenuation: Attenuation is expressed as a percentage
of the difference between the original and final gravities of the
beer. Real attenuation accounts for ethanol, which has less density
than water. Attenuation will vary by beer and yeast strain, typical
ranges for real attenuation are 65-80%.
More Big QC Day details
Note: The following
article was prepared by White Labs Lab Manager Neva Parker in
anticipating of the 3rd Annual Big QC Day. Please note that testing
for this year has been completed.
February is just around the corner, and as you’re ending this year
and looking towards next, remind yourself – how much do you love
your beer?
This slogan is what encouraged us to launch the industry’s
first large-scale analytical testing program for microbreweries and
brewpubs in February of 2007. Our
goal was to encourage beer testing by offering convenience and a low
price, which we were able to do by obtaining a large number of
samples. This year we are
happy to make the testing available for the same low price of $129
for two samples.
The Big QC Day program includes microbiological tests that
comprise wild yeast, aerobic bacteria, and anaerobic bacteria.
The analytical tests were expanded in 2008 to consist of
alcohol by volume, density, real extract, apparent extract, real
attenuation, apparent attenuation, pH, color, IBU, calories, and
total VDK (diacetyl).
All of these tests combined can tell you many things about your
brewery processing and should be an integral part of brewing.
They are an important way to evaluate your products and can
be used to cross-check your own analysis, procedures, or
instruments.
Our aim in continuing to develop this program is to promote
quality control testing and make it affordable to all of our
customers. In these tough
economic times, testing may be something that you might consider
eliminating from your program, but bear in mind the benefits you can
acquire from these tests. We,
at White Labs, strive to contribute to making the best beer possible
so that this industry can continue to grow and thrive.
That is why we hope you continue find these test results
valuable and look forward to your participation in this
industry-wide event in 2009 and years to come.
Big QC Day details
Please order your Big QC Day by phone, 888-5-YEAST-5 by the deadline of Feb.
5 (update: the deadline has passed and no more orders are being
taken at this time). White Labs will ship out boxes Feb. 5-6
and will need them returned no later than Feb. 18.
Final reports should be sent to breweries by mid-March. To view a
sample form that we send to breweries with each QC Day order,
click here.
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