Written by By Aaron Brown

A brewer is like a chef; only the dish they are preparing takes weeks or even years to come together before it’s served. The choices a brewer makes are about coaxing out a desired effect in the final product over a long period of time.

Any of the fundamental ingredients in beer, such as water, malted barley, other grains, hops, and yeast, can have a noticeable influence on the drink that crosses your lips.

The qualities of these ingredients will have an impact on the finished product and will determine everything about the sensory experience; including colour, mouthfeel, flavour, bitterness, aroma, and more. All of these are driven by the inputs a brewer chooses and the brewing techniques they employ.

Today we will look at beers where we can point to yeast as having a specific influence on what we are drinking. Choosing what yeast to use is a crucial decision that every brewer makes, but yeast is often overlooked and it is easy to forget that it brings a lot to the party.

A Brief History of Yeast

Yeast was always known to be important to brewing, but was poorly understood before Louis Pasteur’s pioneering work in the 1850’s and his landmark book in 1876 Études sur la Bière (Studies on Beer – Its Defects, Their Causes, and Procedures for Preservation, With a New Theory of Fermentation).

Until this time experts weren’t even sure if the yeast was necessarily alive or not and fierce debate raged about the nature of microscopic life in general. It is hard to believe today, but some thought Pasteur’s ideas were outrageous.

Pasteur eventually prevailed in showing that the yeast was alive, and that life in general came from the reproduction of other living things. His opponents, chiefly Félix Pouchet, maintained that life could spring spontaneously from sterile organic materials. Today we know that when food spoils the rot, fungus, mould and bacteria were already there, just waiting to thrive and ferment.

Pasteur’s work helped to usher in the application of more rigorous scientific techniques and precision to brewing. This set off a technological revolution in brewing and across the entire food production system. The days where brewers could muddle their way through, using folksy techniques and rules of thumb to manage fermentation, could no longer be sustained.

The advances in microbiology were rapid. Nobody used a pure yeast strain in brewing until 1883 when Emil Christian Hansen isolated individual cells at the Carlsberg brewery laboratory. Today, you can buy pure yeast strains from commercial labs or from local shops like Brewhaven.

Yeast doesn’t just do the work of turning sugar to alcohol and making bubbles in our beer. It also has a taste in and of itself and produces aromatic compounds. Perhaps the easiest way to notice these aromas is to grab a German-style Hefeweizen. Take a whiff before you enjoy it, and you will notice a clove, pepper, banana or bubblegum aroma thanks to the phenols and esters our tiny friends can produce.

Craft Beer

A Bit More About This Style

The word Hefeweizen is German for ‘Yeast’ and ‘Wheat’. The wheat reference is to malted wheat that makes up at least half of the grain bill for this style. These beers are naturally cloudy because of proteins in the wheat and become more so when the yeast from the bottom of the bottle is poured into the beer.

Glassware is important to the beer experience and a Hefeweizen is no exception. You don’t need a perfect glass, just one that won’t get in the way. If you don’t have a Hefeweizen glass handy (it is long, slender, and flares out at the top like a trombone) try to find the tallest and largest glass you can. Hefeweizens are slightly more carbonated than most beers and will have a larger than usual head when poured. It is very easy to spill over the sides so be careful. Your glass should be tall enough to contain all of the beer as well as that extra foam.

At first, pour the beer like you would any other. Keep the glass at 45 degrees as the beer flows in. When the beer is about ¾ of the way done, tilt the glass fully upright and gently pour more beer in until you see foam rise to the top edge of your glass. Save a small bit of beer along with the yeast caked to the bottom of the bottle. The next step is optional, but you can choose to swish the remaining beer and yeast and use it top off your glass. Excessive yeast clouding your beer is usually something you want to avoid, but in this case you’ll be missing out on the full experience of the distinct yeast character.

Look out for real-deal German Hefeweizens (Schneider, Weihenstephan, Paulaner & Erdinger) at the LCBO and get local takes on this style of beer at your favourite bar.