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Before You Drink That Beer ...


There's a good chance that sometime this month you'll find yourself in the company of good friends, sharing some good conversation and possibly a beer or two. You won't be the first and will by no means be the last. It's been happening on a daily basis for more than 5000 years.

Beer was first "invented" by ancient Egyptians or Sumerians, depending on who you speak to. It's truly an old beverage and a fine example of mankind's earliest efforts to harness microbes to work for our benefit. Of course, the product has gone through many refinements over the years. Herbs and spices have mostly made way for hops, with the exception of some craft brews and a couple of special Belgian beers.

So where does the beer industry stand today? Well, simply put, it's huge! A single large brewery can produce in excess of 400 million litres of beer a year. Guinness in Dublin, Ireland, produces 450 million litres annually, and each fermentation is a staggering 200,000 litres. In Canada, Molson's Montreal brewery has fermenters that can hold 540,000 litres. Putting this in mind-boggling perspective, a large-scale brewery can comfortably start a new brew every 90 minutes, thanks to rigorous process engineering, and these usually range from 60,000 to 100,000 litres. If they were to brew, say, 90,000 litres, it would end up as 11,000 cases of 24 bottles. If you were to try to drink all that, it would represent 24 beers per person per day for 30 years! And that's just one brew, in one brewery.

Thirsty Population, Consistent Product

Clearly there is a thirsty population on this planet. Quenching that thirst requires specialists in engineering, microbiology, chemistry, economics, marketing, logistics, and a host of disciplines that touch on many of these domains. One fundamental issue that lies at the center of brewing, and distinguishes it from winemaking, is product conformity. Grapes, and the wine that is produced from them, will change in character every year (referred to as vintage), depending on the prevailing climatic conditions during the growing season, cellar conditions, and a host of other factors. People accept this and almost expect it. At the same time, they expect that when they pick up a bottle of their favourite beer it tastes the same as the last one they had. Yet the ingredients used to make beer also come from nature and their composition will also vary with the climate. How then is it possible to make the product the same every time?

The answer, of course, is through science and engineering. Malted barley is produced, and the yeast cultivated, according to specification. The wort (unfermented beer), in turn, is fermented according to specification. Determining what the specification should be, as well as the tolerances for deviation, comes through rigorous scientific trials. Engineering, brewing science, microbiology, and good old-fashioned teamwork help overcome obstacles in the path to success.

So what kind of science could they possibly be using in beermaking? Let's start with the raw materials. It is important to understand how growth conditions affect the barley composition. That's where plant scientists come in, as they study barley genetics to better understand crop variation and composition. And precision agriculture, a subdomain of agricultural engineering, which involves the use of satellites and artificial neural networks among others, is often employed to spot crop stress and make adjustments to irrigation and fertilization regimens. It's a role that agricultural engineering plays, along with managing irrigation and other field practices.

Alpha and beta amylase enzymes found in malted barley (also found in your mouth and small intestine) are used to break down the starch present in the kernel into maltose and maltotriose, which are chains of two or three linear glucose molecules, respectively. These enzymes are really important and are produced during the malting process. The harvested barley is soaked in water and allowed to start germinating. During germination, the seed produces all the enzymes it needs to utilize the nutrients stored to help a new plant get started. By stopping the germination process at the right time, the malted barley will retain a large percentage of the nutrients (primarily starch and some proteins). The more starch present, the more sugar can be extracted. It's a case of economics: balancing the time taken to extract the sugars with the potential yield. Specially trained malting scientists work in conjunction with chemists to determine the efficiency of their malting process, while plant scientists work towards improving the barley varieties to yield more sugars, faster. There are some courses available in these areas, but often one travels to a brewing school to learn about malting practice. Heriot-Watt University in Scotland offers one such course.

There are many similar issues in hop cultivation. Hops, which provide bitterness and certain aromas in beer, will have varying quantities of alpha acids. It is these acids, found as a resin on hop flowers, that provide the bitterness when boiled in wort. A higher yield of alpha acid makes for a more efficient hop that imparts aroma and bitterness, with less plant material needing to be removed at a later stage. Crossbreeding and strain selection not only improve yields, they are also used to acquire resistance to mildews that affect hop vines.

Once harvested, it is important to process the hops as fast as possible to prevent oxidative degradation. Often, large breweries will use a resin extract. By extracting the resin from hops, using liquid carbon dioxide only, companies are able to standardize the alpha acid content (and conveniently remove plant material that would otherwise have to be removed during the process). Organic chemists along with chemical and process engineers often carry out this work.

Far More Than an Alcohol Factory

Process control, as well as a fair amount of automation in the larger companies, helps to ensure that the brewing process proceeds as intended. Electronic and electrical engineers come to your beer-drinking rescue at this stage.

The wort undergoes fermentation once it has been brewed. Enter our industrial friend, yeast and lots of it. Most brews are inoculated with approximately 10 million yeast cells per millilitre. Yeast cultures normally do not exceed 100 million to 200 million cells per millilitre. So, if you want to ferment 600,000 litres of beer, you need to culture roughly 60,000 litres of yeast. Keeping this much yeast healthy and getting it to ferment in the same manner each time is not that easy. But if you think that's not a big deal, consider this: Yeast is responsible for more than 700 flavour compounds in beer.

Yeast is far more than just an alcohol factory. These flavour compounds are of critical importance in the final product and a large chunk of research goes into understanding how and why yeast produces what they do. Strain selection for making a product is important and the responsibility for this falls on a group comprising master brewers, chemists, flavour panels, and microbiologists. Most breweries guard their strains carefully.

Here's an example of one important compound found in beer, diacetyl. It's a relatively undesirable compound that smells like butterscotch and is detectible at levels as low as 0.1 parts per million (or 0.1 milligrams per litre). During fermentation yeast produces a significant amount of this product, which then has to be reduced before the product is sold. This is one of the primary reasons for aging. After fermentation is finished, the yeast and beer are held in a tank for a prolonged period of time. During this time, the yeast, which is essentially starved, consumes diacetyl in order to produce energy. It's a slow process though, which means tanks are tied up for some time.

Understanding and perfecting this, and other, processes helps breweries produce beer more efficiently. Our fermentation research facility located in the department of bioresource engineering at McGill University in Montreal works closely with breweries and other industries to solve problems with fermentation performance. It's a broad field of work, ranging from genetics right through to scale-up problems. Scientists at the University of British Columbia (UBC) also perform similar research with wines and wine yeast. ( Editor's note: see Next Wave's article on wine research at UBC.)

Traditional Practice, Modern Technologies

Brewing is a very traditional practice, even though modern technologies are employed in production. Although the whole drive to understand the molecular basis of beer production involves modern tools that are used in biotechnology, such as real-time polymerase chain reaction (PCR), gene chips, proteomics, mass spectrometers, and so forth, genetic manipulation is not acceptable in any form--not in any of the raw materials or the yeast. Rather, biotechnology tools are used to study processes and come to an understanding of how to control them as best as possible using other techniques.

Traditional strain-selection techniques are supplemented with strain screening, which can involve examining gene-expression patterns through PCR or understanding global gene expression in relation to environmental factors using gene chips. With an understanding of what a particular brewery is looking for in terms of flavour compounds and other factors, it may be possible to scan for yeast with desirable expression profiles. These advanced techniques are often coupled with gas chromatography as well as other chemical analysis techniques in order to determine the profiles of flavour-active compounds. This could save a lot of time and as the cliché goes, time is money.

So, the brewery has a good strain and they have a beer that's finished fermentation, which is all fine and dandy and we are at once impressed that they could make so much of it. Nevertheless, the beer is not sitting in our fridges yet. It needs to be packaged and shipped to a place near you. The marketing crowd informs the packaging specialists of their plans for this brew, and the latter then need to figure out how to achieve that goal. Should they use glass? What colour? Will the product be exposed to light? How will it be handled? Cans? Kegs? How much do you need to fill per hour? 100,000 cans? It's all possible. There are machines that fill 2000 cans a minute.

Process engineers integrate these machines into lines that can keep up, and packaging specialists figure out what the material properties should be to handle the stresses the beer container(s) might encounter. Graphic designers work on the flash and splash that goes with marketing. Logistics manages the shipments and stock rotation. Hey, sometimes beer can go bad, but good control of stock helps prevent you putting your lips to that 'skunky' brew. Let's have a show of appreciation for those guys that work in the background, making sure that mistakes are minimized! All we do is pick up a case at the store, pop the top, and sip it down. Now you can see there is a whole lot more to it.

So next time you find yourself with a beer in hand, or nearby, use the opportunity to have a good look. Appreciate the clarity, the fine nose, the delicate bubble streams that seem to be just right every time, and if you wish to, savour the flavour and give a toast to the hundreds of people that it took to make that one beer!

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