On Thursday, November 7, I attended an entertaining and intriguing Chemistry seminar presented by Tracy P. Hamilton. The speaker came from Arkansas to share his knowledge of home brewing beer; he has been brewing since 1997. During this presentation, he explained the history and story of beer, the differences between lagers, malts, etc., why beer has certain flavors, and the actual process of brewing beer.
There is no precise date known for when beer was first brewed, but it is believed that the domestic crops used for beer first appeared around 11,000 B.C. They were found in the middle east and used as a food source at first. Hops weren't first used until around 850 AD. Beer was actually discovered on accident by trial and error once the feeling of intoxication was experienced. Brewing even helped contribute to the literacy of people by providing opportunities for citizens to record and keep track of the amount of grain held in warehouses.
The basic process of brewing involves making sugar water and adding yeast; the sugar converts to alcohol and carbon dioxide. On a more specific level, first you need malted barley. Malting is the process of germinating seeds that produce enzymes which break down protein and starch. Then you dry the seeds again. The malted barley must then be gelatinized followed by mixing the grain and hot water to form "the mash". While making the mash, the enzymes within must be held at specific pH and temperature ranges depending on the type of beverage being made. Lautering comes after mashing, this involves rinsing the sugars from the mash (we want maltose, not sucrose). The sugar solution then becomes "wort" and is boiled to remove proteins. Once this is complete, yeast is added after the wort has cooled and aerated. The last step is fermentation; temperature is very important in this step, lagers are held at 50F and ale at 70F. And voila, beer!
Another interesting topic Dr. Hamilton went over was how beers have certain flavors:
H2S - rotten eggs
CO2 - gives a bite
acetaldehyde - green apple
diacetyl - butterscotch, buttery
lactic acid - sour
dimethyl sulfide - cooked corn (means infection is present)
Overall, it was really neat and definitely not your average chemistry seminar!
It is pretty neat to think about the extent to which complex chemical processes go into the making of what seems to be a simple glass of beer. The wort you mentioned, or unfermented malt, used to be made by first baking loaves of bread, crumbling it into bits, adding water, and then straining it. Because so much knowledge has been acquired about the underlying formation of beer, it's literally been reduced to a science that is amended and perfected continuously. So, go beer! Go science!
ReplyDeletehttp://www.rpi.edu/dept/chem-eng/Biotech-Environ/beer/history1.htm
npr also had a cool sciencefriday edition about it:
http://www.sciencefriday.com/segment/08/30/2013/food-failures-beer-home-brew.html
Jenn, actually remember he did say they have an idea about the origination of beer? The Egyptian keg-stand hieroglyphics? It was good seeing you! I might go to the next one for more toffee!
ReplyDeleteMy uncle brews his own beer so I have seen the process in its simplest form but I have never been exposed to the intense chemistry behind it. I did not know it could be so involved and complicated. I personally do not drink beer and hate the taste but I have a new respect for beer brewers.
ReplyDeleteI find it very interesting that the making of beer increased the literacy of those who handled the grain. There is also a great deal of work being out into products that consumers have no idea about; it's funny to think that whenever someone drinks beer, they are drinking chemistry.
ReplyDeleteThis post is really interesting. I personally am not a huge beer fan, but I was surprised to know that hops were not the first flavoring agent! I would have loved to hear about how the different flavors in beer are created, I wish I had gone to this lecture as well. Also, I have had my own experience with a family members well-water having H2S in it... it made everything smell like rotten eggs, I wouldn't think any beer flavored like that would sell very much. Haha.
ReplyDeleteI actually know this house in Greensboro where they have a 5-All-Concert and you pay $5 to drink all the beer you can and attend various concerts in their basement. The interesting part is that they have this party once a year because that’s how long it takes them to brew the beer. I spoke with them a little about it and two of them were actually chemistry majors at UNCG. It’s a very cool process and the fact that they brew 4 different types and the only thing that makes them different is the temperature they make it at.
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