How to make beer 20121031

1.       Equipment and materials

1.1    Equipment:

A Large Pot to boil

Tubing and Clamp to siphon the beer

An Airtight Glass Fermenting Carboy to keep sanitized and don’t leak

A Thermometer 

Bottles not twist-off bottles

A Bottle Capper 

Bottle Caps 

A Sanitizing solution to sanitize everything since beer is easy to be infected   

1.2    Ingredients:

Malt Extract provides substrate to which yeast will feed on to make alcohol

Hops add bitterness 

Liquid Yeast  

Priming Sugar like corn sugar

2.       Stages:

Sanitize Everything First!!!

2.1 Brewing Beer 
Boil the barley seeds for 25 min to add color and flavor complexity. 
Then, add 1 gallon of water , and heat until boiling. 
Add malt extract and stir to make sure it's dissolved. 
Add bittering hops for 1hr, then flavor hops for 15 min, and add the aroma hops for 5 min. 

  

2.2 Cooling and Fermenting 
Cool the wort (hot mixture) to 80F, and then transfer to the sanitized primary fermenting carboy. Add water up to 5 gallons. Measure the gravity of the wort by a hydrometer. Add the liquid yeast when the wort is cool down to 72-78F, and the fermentation process starts. Put on an airlock to keep the wort from contamination with the bacteria.
The 

    

2.3 Tasting 
It seems like nobody can wait for another 2 weeks to taste the beer. Actually, the wort tastes not that good and does not have alcohol at all. See everybody's facial looking when tasting the wort! How funny!!

3. Fermentation behind brewing

We also learned the pathway of glycolysis and the fermentation mechanism of brewing.

Louis Pasteur, a French chemist, is the first one to demonstrate experimentally that fermented beverages are caused by living yeast transforming glucose into ethanol. Moreover, Pasteur demonstrated that only microorganisms are capable of converting sugars into alcohol and defined it as respiration without air..

C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂

Glucose is converted into pyruvic acid during glycolysis. When oxygen is available, pyruvic acid enters the tricarboxylic acid cycle and starts the respiratory chain. As a result of respiration, cells produce 36–38 molecules of ATP for each molecule of glucose oxidized.

In the absence of oxygen, pyruvic acid can follow two different routes. It can be converted into ethanol and carbon dioxide through the alcoholic fermentation pathway, or it can be converted into lactate through the lactic acid fermentation pathway.

Reference:

http://beersmith.com/blog/2009/01/10/how-to-brew-beer-5-steps-for-making-beer-at-home-part-1/

http://www.nature.com/scitable/topicpage/yeast-fermentation-and-the-making-of-beer-14372813