Draught beer quality

Avoid losing sales, perform draught beer quality audits...

A few years ago I discussed with the Chairman of IFBM scientific foundation in Vandoeuvre les Nancy in France, I was told that every time a beer quality consumer problem happens somewhere in France it had a negative impact on the turn-over of the whole french brewery industry, although brewers were not responsible for it.

One of the major problem is the draught beer quality dispensed at sales point to customers, because off-flavours, as biogenic amines toxins produced by lactic acid bacteria may trigger end-user health problems, spreading bad reputation on the brewery of the spoiled beer served. Pubs, restaurants, cafés where drought beer quality is degraded, will be loosing customers without noticing the reason. Do you experience the same as beer producer, pub, restaurant or cafes owners in your country?

Microbreweries, craft brewers, regional breweries and multinational brewery groups are keen to follow strict HACCP guidelines as well during brewing process than during kegging, but one criticial point is usually out of reach for most brewers, the draught beer dispensing system at the beer sales point.




End point beer dispensing system biofilm build-up an issue to solve...

Whatever the sophisticated beer dispensing system, biofilm inside the dispensing system is unavoidable. The most important will be to reduce surface biofilm thickness and size, by regular maintainance and replacement of spare parts, dismantling cleaning and sanitizing any part of beer dispensing system in contact with beer.

beer biofilm formation

Otherwise biofilm will grow and fluid shear forces inside beer dispensing lines will tear off important parts of biofilm some of those containing massive biogene amine producing lactic acid bacteria or acetic acid bacteria releasing acetic acid into the beer when dispensed into the consumer glass,

How to evaluate the beer dispensing biofilm reduction?

How do we know if the beer dispensing system has to sanitized? And how do we know if sanitizing was successful? German guidelines for dispense systems gave threshold values of draught beer ranging <1000 colony forming units/mL for a good beer up to > 50.000 colony forming units/mL be a very bad quality of beer (we speak here of colony forming units, because nobody knows if the colony formed on the agar plate is originating from a single planktonic cell or from a cluster of cells growing on the agar media).

At 10.000 colony forming units/mL dispensing systems are recommended to be cleaned and sanitized. However no indications of the test method was given, besides the fact that all plate count methods are selective and not displaying viable but non culturable strains.

"Forced beer samples" the solution?

It is a well known fact, that hop resistant lactic acid bacteria and
those found in the environment are not able to grow on selective media.
To prevent this problem of microflora not able to grow on agar media, a
post dispense sample incubation method named “forced” post dispense
sampling method was improved by Mallett et al by addition of
cycloheximide to the incubated beer samples for four days,with a
spectrometer reading of the forced sample before incubation and after 96
hours. However as mentioned by the author lots of different yeast are
cycloheximide resistant.

One major inconvenience of the method is the complete ecological change of microbial population not representing the initial beer released microflora, leading to death of strains replaced by others not developped initially. A well known factor identified by whisky microbiologists when analyzing
wort samples travelling only a few hours to the local lab, these few
hours are sufficient to modify completely the original microbiogical
picture when the sample was taken.
Besides waiting 96
hours to know whether beer dispensing systems need to be cleaned or if
sanitizing procedure was successfull is not practical.

Another point of concern is the health issue. Discussing with the brewery industry, it appears that brewers
when performing audits would like to be able to discriminate bacteria
released into consumer’s beer instead of the total yeast-bacteria
A major issue alos is the biogenic amine producing lactic acid bacteria, and the predominant acetic acid bacteria acetic acid releasing acetic acid into the dispensend beer .

It is important to compare biofilm release into dispensed beer before and after cleaning, disinfection and rinsing operation. Is the remaining biofilm sufficiently reduced to avoid releasing into the dispenser? Internal surface of dispensing line may appear crystal clear but may harbor important colonies of microorganisms in its biofilm surface colonizing for example invisible cracks. Visual inspection is usefull in case beer dispensing were very durty, but not sufficient.


Which source of concern: yeast or bacteria?

Experience of professionnals concerning contaminated beer dispensing lines, reveal that major off-flavours released from beer dispensing systems are diacetyl (mainly produced by lactic acid bacteria) and acetic acid (mainly by acetic acid bacteria). No wonder as first surface colonization as referred above are by encapsulated acetic acid bacteria, followed by lactic acid bacteria.


Will rapid lactic acid bacteria/acetic acid bacteria screening tests be available?

The answer is yes, but it will depend if investors are found. The prototype is available, proof of concept validated by repetitive microbiology testing in a Aquitaine Microbiologie research lab, a spin-off of Bordeaux University. My innovation was recently patented in United States. It is graded by Patent lawyers as AAA grade, a grade given to breakthrough technologies with strong intellectual property protection.


My innovation is supported by New Horizons Diagnostics Corporation in Maryland in United States. For more informations concerning the rapid detection principle you can also read this article on Linkedin

Are you a brewer, a brewery consultant or service provider,  and you see the use of such a technology, you are welcome to contact us by email for more informations.