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<   No. 3305   2013-11-10   >

Comic #3305

1 {photo of four sample glasses of different beers}
1 Caption: Beer

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Black Duck Brewery
The bar counter at Black Duck Brewery. Fermenting (steel top) and conditioning (white top) vats in the background. Jars of barley and hops in foreground left.
On my weekend away last week, I drove up the coast of New South Wales from Sydney to the town of Port Macquarie. While there I did some sightseeing, walking along the well maintained walking tracks beside the beaches, along the boardwalk by the riverside, and on the rainforest walk in the Sea Acres reserve. A lot of walking is good for two reasons: to experience the local attractions, and to work off some of the holiday food, which has a tendency to be a bit richer than usual.

Another thing I did was to visit the Black Duck Brewery and take a guided tour of their facility. I always enjoy behind the scenes tours, and industrial sorts of places can be just as fun as artistic and cultural institutions. The tour is fairly short, because it's a small factory, contained within a single large room. The brewer begins by sitting down at a table with you, with a set of glass jars containing the basic ingredients for making beer.

The first contains grains of barley, a bit larger than large rice grains. They are a pale, golden colour. The next jar contains malted and roasted barley, with the grains being dark brown. This is the first step in the brewing process. Malting is a process in which the grains are allowed to germinate by soaking them in water. This converts some of the starches in the grain into sugars of various types, which is necessary for the later fermentation.

The germination is halted by drying and heating the grains, and here is where the first differences in the brewing process can lead to differences in the end result. Heating the malted grain to higher temperatures can begin to roast it, making the grains darker and producing aromatic compounds related to caramelisation of the sugars, and eventually the distinct dark toffee notes bordering on "burnt" aromas and flavours. Lighter grains lead to lighter beers, both in colour and flavour, while darker roasts produce darker, more complexly flavoured beers.

Behind the scenes at Black Duck
Mash tun (centre left) for mashing the grain and kettle (centre) for boiling wort.
The malted grains are cracked open with a gentle milling, then placed in a container known as a mash tun, where hot water is added to create a cereal mash, a bit like a porridge (only runnier). The mash is heated to around 70-80°C in various stages; not boiling, but definitely far too hot for a warm bath. This extracts the starches, and enzymes from the grain, and converts more of the starch into sugars. This mashing process is where the brewer has a lot of control over the appearance and flavour of the final product, because pausing the heating at various temperatures for different amounts of time activates and deactivates different enzymes in the mash, changing the proportions of different types of sugars and other compounds, thus altering the flavour profile.

Mashing lasts up to a couple of hours. Once the brewer is satisfied, the liquid is drained off into another container, called a brewing kettle. Most of the solid remains of the grains are filtered out at this stage, either using a mechanical filter or by draining the liquid through the mash itself, leaving most of it behind. In the kettle, the liquid, now called wort, is brought to a boil. This deactivates all of the enzymes, halts the production of further sugar, sterilises the solution of any harmful bacteria, and also boils off some undesirable volatile compounds such as sulphides (which carry a "rotten vegetable" aroma). Also during this stage, the flavouring ingredient of hops is added.

Hops are the flowers of the hop vine, specifically the female flowers. They have been used to flavour beer for centuries, perhaps thousands of years. Besides just tradition, adding hops adds a bitter flavour to offset the sweetness of the malt, as well as fruity notes that make a pleasing beer. Hops also acts as a preservative, inhibiting the growth of harmful microorganisms that can spoil the beer or interfere with the later fermenting process of the yeast. Next time you think of drinking beer as a stereotypically masculine activity, remember that beer is flavoured with flowers, just like chamomile tea or dandelion wine - and not even male flowers, just the female ones! Another flavouring commonly added to beer in historical times before the widespread adoption of hops, and still used for some specialty beers today, is gruit, a mixture of herbs.

Little Creatures
A larger brewery: Little Creatures in Fremantle, Western Australia.
At this point we return to our brewer with his jars on the table, as one of them contains hops flowers. Adding fresh flowers is desirable because of the freshness and flavour, but hops are highly perishable and difficult to transport. So the brewer has another jar, which contains compressed pellets that resemble rabbit feed pellets. These are dried hops flowers in pellet form. They can be shipped easily from hops farms.

Growing hops requires a cool climate, much like apples. While this is easy to find in the northern hemisphere, in Australia the growing region is restricted to Tasmania and the very southernmost parts of Victoria, which is about 1200 kilometres south of this brewery. So here they use the compressed pellets.

Boiling the wort takes about an hour. The hops can be added near the beginning or near the end of the boil, or in multiple stages, depending on the flavour profile the brewer aims to achieve. Earlier addition brings out more of the hops flavours and aromas. However some of the hops flavours are also in volatile compounds that are quickly removed by boiling, so if these are desired then at the end of the boil the hot wort is piped through a separate device known as a hopback. This contains fresh hops or pellets, and allows the hot wort to pick up the volatile flavour compounds just before being cooled.

The hot wort is cooled quickly to room temperature or just below by piping it through a heat exchanger. This is a series of pipes surrounded by a tank of cold water. Heat flows rapidly from the wort in the pipes into the cold water, which is pumped through to remove the now warmer water and replace it with colder water. From the heat exchanger, the now cool wort is put into a vat. The wort needs to be cooled quickly both to retain any volatile hops compounds and also to avoid a long delay in adding the yeast to begin fermentation.

Potters Brewery
Potters Brewery, Pokolbin, New South Wales.
Yeasts are a group of single-celled fungal organisms. They digest carbohydrates, particularly sugars, and convert them into carbon dioxide and alcohol. Yeast is commonly used in baking bread and other leavened dough products, where the carbon dioxide forms bubbles in the dough, causing it to rise, giving bread its slightly airy texture. Any alcohol produced is evaporated off during the baking process. In brewing, in contrast, the alcohol is desired, so the developing brew is kept cool. Heat also kills yeast, which is why the hot wort needs to be cooled down before the yeast is added. Brewing typically uses different species of yeast to baking.

There are a few different methods of fermenting beer. The two main methods use different strains of yeast with different properties. One ferments at cool temperatures, around 10°C, and does so near the bottom of the fermentation vat. This type of yeast can completely break down all of the sugars in the wort (into alcohol and carbon dioxide), leaving a dry (i.e. non-sweet) style of beer, known as a lager. A different strain of yeast ferments at higher temperatures, around 20°C, and floats near the top of the brewing mixture, producing a foamy head as it does so. This yeast can only partially break down the sugars from the malted grain, leaving behind some types of sugar, which give the resulting beer a characteristic slight sweetness. It also produce esters, organic compounds such as those found in various fruits, which can give the beer subtle aromas and flavours of apples, bananas, pineapples, and various other fruits. The resulting type of beer is called an ale.

Chicha, corn beer home brewed in Peru.
Fermentation can take from a few days for ales, up to a few weeks for lagers. The cooler fermenting temperature of lagers makes the action of the yeast slower, so lengthening the process. The goal is to let the yeast consume as much of the sugar as it can - interrupting the fermentation earlier will leave additional residual sweetness in the beer. (Though remember that ales always leave some sugars which the yeast cannot digest.) After fermentation, the beer is aged, or conditioned. It is drained from the fermenting vat to a storage vat, filtering off much of the now dead yeast along the way. The ageing process allows the remaining chemical reactions time to settle down, as well as allowing any particulate matter in the beer to settle out.

Lagers are typically matured at near-freezing temperatures for several months, during which the cool-temperature yeast remains still slightly active, adding additional alcohol and carbonation. Ales can also have a secondary fermentation during the maturing period, if a little fresh wort is added. At the end of the conditioning time, the beer is packaged in bottles or kegs for distribution and consumption. Even at this stage, a slight further fermentation can take place, resulting in what are known as "bottle fermented" beers. So the whole modern process of making beer takes several months, to perhaps a year or more.

Just before bottling, the beer is often filtered, to remove any last remaining solids and ensure a clear end product. Some producers choose not to filter the beer, simply allowing solids to settle out and then drawing the liquid off the top of the vat. This can result in a slightly cloudy appearance to the beer, which does not really detract from the taste, and can appeal to people interested in a "less processed" beer. The Black Duck Brewery I visited does not filter their beers, for example. In fact, depending on demand and current stocks of bottled product, they leave their beers to settle for different amounts of time, so the beer can come out with different degrees of cloudiness from batch to batch.

Number 6
Schlenkerla brewery/tavern in Bamberg, home of Rauchbier.
The difference in the two basic types of beer explains a perennial puzzle that even I, as a non-beer-drinking teenager, knew about when growing up: the fact that in England they serve "warm beer", whereas everybody else knows beer should be served icy cold. This oversimplification to the point of seeming strangeness is a reflection of the fact that lagers have become the most common form of beer in much of the world, since the introduction of refrigeration technology. Lagers do not contain many volatile aromatic compounds and rely mostly on the hops to impart flavour. This style of drink, much like light white wines, benefits from being served chilled. An icy cold beer is also a good thirst quencher after a hard day working in hot weather. England, however, does not have weather as hot as many other parts of the world, and there the drinking tradition has tended to stay associated with ales. The volatile flavour compounds in ales are masked if served too cold, so these beers are better served at something just below room temperature. Although still cool, to someone raised on icy cold lager, this seems disgustingly like "warm beer". However, as I discovered when I visited England, if you try it with an open mind, ales are very pleasant to drink this way.

Ale is the older historical form of beer, since it could be fermented at room temperature, without needing any refrigeration. The exact process would have been a bit simpler than what I've described here, since the technology was less developed. But ale has a very long history, particularly in England, and also across Europe. In the medieval period, it became customary for people (including children) to drink ale with a low alcohol content, rather than water. This was a good thing for two reasons: firstly, ale has significant nutritional value, providing calories and some grain nutrients to people who otherwise had rather poor diets. Secondly, ale was actually safer than water to drink, because the boiling and fermenting process destroyed most of the harmful microorganisms that tended to reside in waterways near human habitation at the time. Such low-alcohol ales were known as small beer, an expression which can still be heard occasionally today. Also, to further shatter the image of beer as a masculine activity, most of the ale brewed in these times was done by women, in small cottage industry establishments.

Not sure which beer to have? Try 'em all!
Beer sampler at Mudgee Brewing Company, Mudgee, New South Wales. Yes, I seem to have visited a lot of breweries...
Besides barley, you can also make beer from other things. Wheat beer is, as the name suggests, made from wheat, although it usually still has barley in the grain mixture. Beer can also be made from millet, sorghum, rye, oats, rice, and even bananas. Historically, the Americas did not have access to Old World grains, so made beer from corn (i.e. maize). The process invented independently by the Inca is surprisingly similar, involving germinating the corn seeds, boiling them, them allowing them to ferment. The resulting corn beer is known as chicha. Many people in the Andes regions brew it today.

You can do other things to modify beer as well. Rauchbier is a distinct smoky beer developed in the German town of Bamberg. It is made by smoking the malted barley before mashing. You can introduce various fruits or vegetables to the wort to transfer some of their flavours and aromas into the beer. During fermentation, various other strains of yeast can be introduced, either deliberately added or by exposing the beer to the air in open-topped vats. This is generally termed wild fermentation, and can result in strains of yeast that impart a distinct sour flavour to the beer, in a way similar to how sourdough bread differs from other breads.

Back to the brewery: after my tour of the brewing machinery, I tried sampling some of the beers. Black Duck brews a total of eight different styles of ale - they don't make lagers. They range from very pale and light to very dark and rich in heavy flavours. A sampler of four small glasses is available and I choose a selection across the range. The brewer pours them and arranges them from light to dark, recommending tasting them in that order. This is for the same reason that wines are tasted in a sequence from lighter to more intense - you can better appreciate the more subtly flavoured varieties when your palate is fresh, rather than soon after tasting something with a strong flavour. The four beers are shown in the title image, from left to right (though I drink them right to left): Phoenix (a stout style beer), Dark Ale, Heron's Craic (an Irish style red ale), and Platypus (an Australian pale ale). I offset the drink with one of the ploughman's lunch platters that they also sell at the brewery. It's a hearty meal including different types of cheeses, sliced meats, and relishes and my wife and I split it as our lunch for the day.

If you get the chance, I recommend visiting a brewery that offers behind the scenes tours and samplers of the various brews. The best bets are probably small boutique and craft brewers, rather than big national or multinational brands. Trying a wide variety of beers in a tasting session is a good way to get an appreciation for the differences in aroma and flavour, and finding styles you like. (A similar thing applies to wines, but that's a story for another day...)

It's also fascinating to learn just how much science is behind the process. Modern brewers are not rough and tumble characters with simple ways. Listening to our brewer go through the process of making beer, you realise he's talking in terms of complicated chemical and biological reactions. He needs to understand the interactions of all parts of this process to make the decisions that lead to various styles of end product, and that requires knowledge, experience, and creativity. As with many things, beer is both science and art.

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Last Modified: Sunday, 10 November 2013; 22:03:17 PST.
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