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MBC Brewing Philosophy – for the beer and brewing nerds!
by MBC head brewer Tom Casey, B.Sc. Biotechnology


Brewing can be considered the original form of biotechnology, which is defined as the exploitation of microorganisms to produce a substance, in the case of brewing the microorganism is yeast and the product is beer.  I hate to use the word exploitation in relation to brewing yeast, I prefer the phrase “aquesence of yeast to produce an alcohol based beverage of the Gods”!!  For millenia brewers knew nothing of the chemical, biochechical and biologics process’ which make up the brewing process but they knew that they needed to control the various stages of the process to get the optimal results.  Today we have a much better but by no means complete understanding of why precise control of various parameters is critical and we make every effort to follow the same procedure for each batch to ensure the production of a consistently high quality product.  However, for any given parameter there is typically a wide range within which the process will still work, but there is a narrow range which gives the optimal results.  This is true for the grist to water ratio of the mash, the mash temperature and pH, oxygen concentration, yeast pitching rate, fermentation temperature, etc.  The exercise of determining the optimal setting for each of these parameters is called “Process Characterisation” in the biotechnology industry.  In simple terms it required multiple small batches to be brewed and only one parameter changed for each batch to determine what the optimal range is.  This is a time consuming process but the end result is well worth it, as the final beer will be a pleasure to drink.  At the end of the characterisation process you find, what I like to call, the “Happy Place” for the yeast being used and the entire production process.  Different yeasts have very different happy places so the iterative characterisation process must be repeated for each new yeast and beer introduced.  I’ve produced my share of poor batches but even bad batches are useful as you know not to repeat it! Detailed documentation is critical to ensuring all the information is captured during the characterisation process.  This characterisation process is a very important part of the science of brewing.  The vast majority of home brewers who contribute to on-line forums are giving their honest opinion on a given topic and are very helpful.  However, I never cease to be amazed by on-line threads on various yeasts where some home brewers frequently dismiss a given yeast completely out of hand when I know from personal experience that under the right conditions the yeast in question produces a fantastic beer.  The homebrewing industry has its share of self-appointed experts who know very little of the biochemistry of brewing and follow a “one size fits all” approach.  They can produce good beers but only with yeast strains which fit their specific brewing conditions, e.g. water chemistry, fermentation temperature, etc..  Ok I’m starting to rant!!


During MBC brewery tours I’m frequently asked what’s the most important element in brewing a good beer.  There is no short answer to this question as producing a good beer requires attention to multiple parameters and elements.  However, even if it’s never formally documented, all good brewers have a general high level “brewing philosophy” which they develop over years of experimenting, testing and commercial brewing.  At MBC we have developed a clear brewing philosophy which I hope to explain in this article.

I got my first proper exposure to brewing while studying Biotechnology at university in Dublin and developed fermentation technology skills during my time working in the US in the early 90s, when the microbrewing industry was really starting to take off.  However, it wasn’t until I moved to Sweden in 2007 that I started to brew more frequently and acquired professional brewing equipment and instrumentation.  Over the years I obtained numerous brewing books and was an avid reader of on-line brewing forums, which provided invaluable information and in-sights.  However, as with most crafts there is no replacement for hands on experience and “real world” training.  Thus, I started infusing the kitchen with the beautiful sweet aroma of crushed malt soaked in hot water and boiled hops.  After about four batches I was sent packing to the garage as my wife and kids couldn’t stand the “stink” – how dare they!!

While having a third level education in the life sciences and extensive experience in fermentation technology is definitely an advantage when brewing beer commercially, it is by no means a guarantee for success.  As the old vantage goes, brewing is both an art and a science, which is something that I can definitely attest to.  Consistently brewing really good beers with lots of character requires a strong element of both.  The art comes in the form of the ingredient selection, the tried and tested procedure followed, the balanced flavour determination, patience with the fermentation, the right liquid yeast for the brew, hop combinations for dry hopping and most of all the taste experience.  The science comes in the form of sanitary equipment design and operation, yeast culturing and handling, controlling and monitoring the critical parameters during the various stages of the beer production process, from the mash temp & pH, to the wort cooling rate, to the yeast pitching rate, to the oxygen concentration and many more besides.  During brewery tours I often point to our lab instrumentation which I considered every bit as critical as the brewing equipment itself.


In any case, to get back to the subject at hand, at MBC our brewing philosophy is based on our characterisation studies which in general have shown that a slower extended fermentation with the correct liquid yeast results in a healthier “unstressed” yeast which produces a superior product.  Much like the “slow food” movement, we firmly believe in slow fermentation.  Many within the microbrewing industry do not consider the “well being” of the yeast to be important, it’s just another microorganism which must be handled carefully to avoid contamination but it’s just a tool for making the product of interest.  Without starting to sound like a yeast “welfare” advocate, years of experience within the biotech industry have thought me to consider the “health” of this single cell microrganisms, much as you would consider the health of a multicellular organism.  With our lofty digital microscope, cell counting plate and dye we ensure that our in house cultured liquid yeast has good viability before we inoculate the cooled wort.  Exactly why a slower fermentation is better for the final beer is down to the myriad of biochemical process’ occurring during fermentation, understanding which, as the saying goes, is above my pay scale!  We have also observed that the harvested yeast from a slow fermentation has a higher viability than that harvested from a more rapid fermentation.   Don’t know why this is the case but the simple fact of the matter is that the beer produced from slow fermentations is superior to that produced from rapid fermentations.  So, for us the formula for success on the fermentation side of the process is:

Healthy Liquid Yeast + Slow Fermentation = Better Beer!!

Achieving this slow fermentation requires accurate control of parameters from the mash process forward.  Slow fermentation ties up equipment for longer which limits output but at MBC we know it’s worth it!  For me one of the biggest difference between commercial breweries and microbreweries is that the former aim for fast throughput, make maximum use of physical and chemical aids to accelerate the brewing, fermentation and maturation (if there is any) process.  Microbreweries in general give beer more time to develop and mature.  Large commercial breweries generally have large labs and they strive to develop yeasts and associated manufacturing processes which will deliver a satisfactory beer in the fastest possible time.  At MBC we are extremely patient with our yeast and give it as much time as necessary to achieve the optimal flavour, taste and yeast that live happily ever after!!!

Sláinte (That’s Irish for health),


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