Beer 101: Beer Gets Scientific

08-01-2016, The BeerVibe Crew

Beer Gets Scientific Beer Review Blog

It was notable progress in brewing when beer-makers learned to distinguish between warm-brewed ales
and cold-brewed lagers, but quite a number of breakthroughs were needed to come up with the beer
we enjoy today. The experienced brewster of old could tell by the feel, smell, appearance, and taste
when a mash was ready. She didn’t have clocks or any other accurate timepiece to help her. How did
they know when the malt was the right temperature? Did the brewing monk have to stick his finger in
it? There was always variation from one batch of brew to the next, and sometimes it would just fail.

Science and technology moved the art and science of beer right along. Here are just a few of the


Mechanical clocks seemed to have existed somewhere since around 996; but they had to wait until the

late Middle Ages, with numerous improvements and the inventions of the mainspring and the

pendulum clock when they became more widely available. If the brewer owned a clock, he could keep

the malted grains in the kiln for a specific amount of time for some consistent results.

The practical thermometer was invented by Gabriel Daniel Fahrenheit in 1714, and improvements were

made. Now the brewer could let his wort ferment at more specific temperatures.

Antony van Leeuwenhoek invented the practical microscope in 1771, and was able to see for the first

time yeast cells in beer, although he did not know what he was looking at; or even that it was something


In 1789 the French chemist Antoine Laurent Lavoisier discovered that carbon dioxide and ethyl alcohol

were the products of fermentation. It is somehow comforting to know that beer was not the product of

rot and putrefaction.

Malted grains were dried in smoky kilns; which left the beer with a dirty, smoky taste. In 1818 the grains

were dried in indirectly heated kilns, where the grain touched nothing dirtier than clean hot air, and the

beer had an improved flavor.

We are now getting closer to our day, and our beer. The role of yeast in fermentation was yet to be


The German scientist Theodor Schwann made the discovery (well known to us today) that cells are the

living things that make up living tissue. He discovered that yeast cells were alive and ate sugar, hence he

called yeast “sugar fungus.” Yeast in Latin became known as saccharomyces, which means sugar fungus.

He also saw that fermentation occurred in the absence of air, that the little fungi worked using an

anaerobic process.

In 1843 the Bohemian chemist Carl Joseph Napoleon Balling created the first hydrometer, which when

used in brewing measured the amount of solid substances dissolved in the wort. Hydrometers see much

use in the brewing industry today.

Luis Pasteur gave us pasteurization, which gave us beer without the bacteria. Pasteur also gave us the

ability to control the environment in the wort. He learned that if he increased oxygen through aeration,

then the yeast would gobble up and metabolize sugar, and rapidly increase their population. When

enough yeast cells were in the pot, the time then came to stop metabolizing and start fermentation by

depriving the wort of air. This became known as the Pasteur Effect, which says: “Oxygen suppresses

fermentation, its absence stimulates it.”

Out of the Carlsberg Brewing Company in Belgium, in 1881; botanist and fungi authority Emil Christian

Hansen classified brewer’s yeasts into the two main types: the top fermenting ales, and the bottom

cold-fermenting lagers. Around 1890 he grew different strains of pure yeast, and also saw how the

varieties of yeast within the two major types imparted their own unique flavors to the beers. He

insisted on using only pure yeasts, not wild ones. (It is noteworthy that some Belgian brewers today still

use the wild yeasts floating around in their breweries)

In 1890 the British chemist Cornelius O’Sullivan discovered how enzymes worked in converting starches

into sugars in malted grains. In 1873 a German engineer named Carl von Linde created an ammonia cold

machine, making precise control of brewing temperatures easier, and allowing brewers of cold-

fermenting lagers to brew all year long.

By the end of the 19 th century, what they drank we today would readily recognize as beer.


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