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The final metabolite of yeast (fermented sugar)
Why was fermentation an advantage in hot climates?
Fermentation inhibits bacterial growth. It some climates it was difficult to find clean water. Fermented beverages were consumed and used to decontaminate water.
How does fermentation inhibit bacterial growth?
It affects the permeability of cytoplasmic membranes of bacterial which in turn does inhibits their growth.
Fermentation - aerobic or anerobic?
an anerobic process
Why did the Babylonians brew slightly sour beer? And why was this important?
Lactic acid which prolonged storage life of the beer because the bacteria couldn't survive as easy.
What is the oldest biotechnology?
What kind of beer did the Celtics and Germanics brew?
Mead which was a sour tasting beer that was stored in vessels underground (500L @ 10C)
What type of beer did Egyptians brew and when?
2400 bc Darker, with an alcohol content of 12-15%.
Egyptians were the first to bottle their beer.
Describe the process of midieval beer brewing.
Soaking barley or emmer wheat in water and letting it germinate.
Describe modern day brewing.
- Germinating barley into malt.
- Step #1: Barley is soaked in water
- Step #2: left to germinate for 7 days @ 59-64F
- Step #3: Mixture is crushed, mixed with water, and turned for a few hours till starch is broken down into glucose, maltose, and various enzymes by amylases (Saccharification)
- Step #4: Hops are added giving the beer a bitter taste and the mixture is now called wort.
- Step #5: Wort is poured into a fermentation vessel where yest is added to begin the fermentation process
- Step #6: Maturation: After fermentation, the beer is allowed to mature in large tanks
- Step #7: Beer is heated to kill any noxious microbes
Breakdown of starch into maltose glucose and various other sugars
What does Beta-Cellulases do?
breaks down the oter layers of the barley grain for Alpha-amylase