Beer Fermentation: Understanding the Process and History
Beer Fermentation is a magical process in your home brewery. The process is not very well understood by beginning homebrewers, so it is usually where many mistakes occur. Most will pitch the yeast that came with the kit and hopes for the best. It is an essential part of the brewing process. Learning about what’s going on in the fermenter will make you a better brewer. Beer fermentation can be controlled, like many other parts of the brewing process. Before you learn to control it, you need to understand it.
Beer has been made since prehistoric times by people worldwide without understanding the scientific processes. Most likely, the first beer fermentations were spontaneous with wild yeast. Wild yeast lives everywhere. Mead was probably the first fermented liquid and could have occurred as rainwater filled a cavity of honey in a tree. Wild yeasts present began fermenting the liquid into alcohol. Once man discovered the divine inebriating effects of alcohol, alcohol has been an important part of our lives ever since.
At first, the beer fermentation process wasn’t understood. Those that stumbled on ways to inoculate the beverage with yeast consistently were probably treated like magicians with divine magical powers. Various ways were discovered to save and transfer yeast from one batch to another. Whether it was by stirring the beer, wine, or mead with the same paddle every time, or adding fruit, then removing and saving the fruit for the next batch, being able to ensure a batch of beer would ferment was key to improving the quality of ancient fermented beverages.
In ancient Egypt, beer was made by adding a sourdough (which contained the yeast) to damp freshly germinated barley and baking it gently until it formed a crust. This would allow the loaves to be stored for a period without spoiling. The loaves were broken up in rainwater and allowed to ferment into beer. The first beer was probably bland or, worse, flat and unfiltered. Most had to be drunk through filtering straws to keep the bitter residue out.
Beer gave the ancient man a reliable way of hydrating since water supplies were mostly contaminated. Beer was given to women, children as well as men.
It has been speculated that civilization formed from the need to grow cereal crops for beer. Nomadic hunter-gatherers settled down to help plant, harvest, and store barley.
Once beer fermentation processes and yeast, in particular, were understood, the face of brewing changed forever. Sanitation became important along with yeast propagation. The resulting improvements in the quality of beer were probably impressive. Of course, no one can know what the beer tasted like even a few hundred years ago. Go. but with our scientific knowledge, we can speculate and get a good idea.
In 1836, Cagniard de Latour proved that yeast in beer was living organisms, not chemicals, as everyone believed. He also showed that these yeast cells were necessary if fermentation into alcohol was to take place. But saying that yeast was necessary and that they were the single cause of beer’s fermentation were two different things.
In 1860, Louis Pasteur wasn’t the first person to discover yeast. But he was the first to understand that beer’s fermentation was caused by living organisms and that those organisms were yeast cells. Mr. Pasteur then went on to prove that yeast didn’t need oxygen to live like most organisms. When in the presence of oxygen, the yeast would multiply, and when all the oxygen was consumed, it would then begin fermentation. Louis Pasteur invented pasteurization to kill the yeast and halt further fermentation. Pasteurization was applied to beer around 1876, and the rest is history.
That’s why it is so important to keep sanitization at the forefront of your mind when making beer, wine, or mead. The yeast cells must have a chance to multiply and dominate the fermentation so other unwanted contaminating organisms can’t have a chance to gain a foothold and spoil your beer. The faster the onset of active fermentation, the less chance of contamination. This is why we make yeast starters, to give the yeast a chance to grow faster than any other organism and thus crowd them out of the picture. They are still there, but in such minute amounts that their effects are not noticed in the flavor, aromas, and appearance of your beer.