Written by joet
RateBeer Archives > Craft Beer Introduction
How Beer Is Brewed
A simple introduction to beer and brewingDecember 9, 2004
Santa Rosa, CALIFORNIA -
Brewing, or the process of some yeast converting vegetable sugars to alcohol, is as ancient as these organisms themselves. Typical beer histories explain beer brewing as being 10,000 or more years old and when you’re talking about humans fermenting barley in Mesopotamian, that’s correct, but in order to explain the process of beer brewing, it’s important to point out even more ancient origins.
Alcohol is created when a yeast, a microscopic single-cell organism, comes into contact with plant sugars. These plant sugars can come from fruit, like the sweet sugars of grapes make wine, or from grains, as with beer. Most plants produce complex carbohydrates in abundance and sugars are simply simple or broken down complex carbohydrates like starches. When the yeast comes into contact with the sugars, it consumes sugars as an energy source and produces alcohol and carbon dioxide as waste.
You might then imagine that a beer was created before humans arrived on the face of the earth. The only ingredients needed would be some plant sugars, some water, and some yeast. Picture an ancient volcano oozing lava down its slopes and into a reedy bog lined with barley. The resultant boil converts some of the barley starch to sugars and the liquid is then inoculated by airborne yeasts. Those little yeasts go to town on the sugars and a lucky ancient invertebrate gets a taste of ambrosia. Wham! You got beer.
Despite the great ingenuity of brewers, the basic beer brewing process has remained essentially the same for not just thousands or tens of thousands of years but perhaps for ten million years. It consists of four basic steps.
1) Grain Processing – The brewer employs various methods for turning grain into a fermentable product. Here are the basics.
Germination – The grain is steeped in water and soaked to encourage sprouting. Sprouting releases a special enzyme that catalyzes or helps the conversion of complex carbohydrates into simple, fermentable sugars.
Kilning - The grain is dried and roasted. This kills the sprout and provides the grain with roasted grain flavors and color. Lighter colored beers are more lightly roasted. Darker beers are more darkly roasted.
Milling – The grain is cracked and the sprouts removed. This crushing allows the grain to be better exposed to the boiling water. This helps convert more sugars and more efficiently kill bacteria in the grain.
Mashing – Sugars are created from complex carbohydrates or starches in the grain by simply applying heat. Chemical bonds break and the resulting pieces are smaller, simple carbohydrates – sugars that can be fermented by the yeast.
2) Boiling – Hops and flavorings are added to this grain sugar and water mixture called wort (pronounced wert). Boiling helps to kill all bacteria in order to eliminate competition for the brewer’s yeast and, as part of the mashing process, to break down complex carbohydrates into smaller, simple carbohydrates – sugars – that are fermentable.
3) Pitching – The wort is cooled to a temperature perfect for the particular brewers yeast to enjoy a competitive advantage against any stray bacteria for the wort’s sugars. The yeast is then pitched and immediately begins to quickly reproduce. Pitching a yeast is a relatively new step in brewing. Ancient beers used wild, airborne yeasts to inoculate their wort.
4) Fermentation – The yeast’s biological process consumes sugars and produces carbon dioxide (CO2) and ethyl alcohol (EtOH or ethanol). Some of this CO2 is allowed to escape and some is used to carbonate the beer so that it’s bubbly.
That’s it! Beer brewing is ancient and consists of these four basic steps. To learn more about brewing beer, the history of beer, or the science of beer, I encourage you to tour a local microbrewery or get started with home brewing. You can find more information on these topics here at RateBeer.
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