Beer, the age old gift that keeps on giving.
Beer, the classic drink that has been loved by millions for thousands of year. Whether it is hoppy or sweet, an ale or stout, the chemistry, behind beer is amazing look into how a delicious drink can be made from water, flowers, barley and yeast are used to make a modern brew. There are many twists, tips and tricks that can be used to provide differing styles, flavours and colours to a beer but the the focus today will be on an ale.
How is it made?
Beer has been made for thousands of years in one form or another. At its core all beer is created with the four basic ingredients. These are water, hops, barley and yeast. In years gone by beer was made with wooden barrels and imprecise measurements that made each brew a unique. However with modern record keeping and access to precise and accurate measuring devices, many breweries have been churning out consistent beers for years.
First barley is ground down so that it will increase the the surface area to lead to faster and more complete reactions with the water. This follows closely with La Chateliers principals of increasing reaction rate with increased surface area, providing more sites for a reaction to take place.
Next a substance called wort is produced. This occurs when the milled barley is added to water. This produces a sweet grainy mix. The wort is then boiled and hops added. Hops are a flower that has antibacterial properties that before sterile equipment was common could sneak in through the other ingredients. The hops also serve to balance the sweetness with a bitterness. A bitter beer will have a lot of hops added to it.
This boiling step also serves to denature proteins and breach down complex sugars into something that can be used by the yeast.
Once the mix is cooled yeast is added. This addition of yeast will turn the sugars produced by previous steps into ethyl alcohol and carbon dioxide. This gives the beer its alcohol percentage as well as producing the carbon dioxide that gives beer its characteristic bubbles.
The beer is then left to mature in tankers before being filtered and bottled, and drunk of course!
The history of beer?
Early writing tablet recording the allocation of beer. By Babel Stone (CC BY-SA 3.0) via wikimedia commons
Beer is the oldest known recipe in the world with notes dating back to 5000BCE. In ancient Egypt. There has been yeast residue found in ancient Mesopotamian sites suggesting beer could be even older still, there has been no written evidence of the production of beer.
Beer as we think about it today first originated in Middle Ages Northern Europe where there was an ample supply of barley to be turned into beer. It At the time there was competition with a fruit and botanical blend called gruit and hops. In the end hops won not because of taste but simply because it was cheaper and required less barley making it easier to produce.
In the 16th century a Bavarian law was passed saying that beer shall only be brewed from hops, barley, yeast and water.
The chemistry behind the beer?
During the brewing process the alcohol and fizziness of the beer has to come from somewhere. It iOS produced yeast. Yeast is a living organism that eats sugars and then once consumed produces the alcohol and carbon dioxide.
This reaction is usually left to run for a long time to produce the large amount of alcohol required for an entire vat of beer to be made. Once the desired alcohol level has been reached the yeast can be killed off through either heat or hostile environmental conditions.