Brew beer in our class
The principle of making beer: Ethanol fermentation is a biological process in which sugars and sucrose is converting into cellular energy, and thereby produces ethanol and carbon dioxide as metabolic waste products. Yeast, an eukaryotic organism is well known as fermentation. Yeast is able to converted starch to fermentable sugars (mostly glucose) by the enzyme a-amylase. Yeast grows and ferments glucose through pyruvic acid to ethanol with liberation of carbon dioxide. Saccharomyces cerevisiae is the only commercial organism which is used for alcohol production.
Material and Method:
Large nylon bag for holding the grains, Stockpot, with a tightfitting lid, Thermometer, Wooden spoon,Timer,Small linen bag for holding the hops, PBW cleaner, StarSan sanitizer solutionSpray bottle, Carboy for fermenting with lids., Funnel. Spring water, Sugar, Pale ale malt, crushed. Munich malt, crushed, Cascade hops, a lot of ice, White labs California Ale Yeast.
Procedures:
Fig.1. The manual of brew beer
Fig. 2. Heat the stockpot with 2 gallon spring water.
Fig. 3. Put the malt gains to nylon bag and put into stockpot and cook for 30 mints.
Fig. 3. Put the malt gains to nylon bag and put into stockpot and cook for 30 mints.
Fig.4. Lift the grains bag entire out of the stockpot, remain the bag over the pot for 1-2 mints make sure all of the liquid was filter from the bag.
Fig.5. Add malt extract into stockpot, boil it. During the time gently stir the pot, mix them well.
Fig.6. Add the hops in. We also get the chance to taste it. It does not taste as good as I expecting. However, Dr. Shaw and Dr. Ebbole like it very much.
Fig. 7. During this time, we also use the sanitize solution to clean and sanitize the carboy.
Fig. 8. Sugar also can be add to increase the concentration of sugar and help to yield more ethanol at the end.
9: Cool down the stockpot, and fill in the carboy. Saccharomyces cerevisiae was added in at this step.
Fig.10. To record the original density, we suck out small amount of brew and check the gravity which is able to indicate the density.
Fig.12. We stock it at Dr. Ebbole’s office, and cover with somebody’s coat. This will keep it warm and avoid the light which will promote the yeast’s fermentation in the carboy. However, it looks a little bit scary, I am not very confidence it will taste like beer...
Fig.13. 14 days later, before we could further carbonate the brew, we need to transfer it to a clean carboy because as fig showed, a lot of scummy were sediment at the bottom of carboy. This also indicates that the yeast has digested the gains, sugar, and malt whcih we added very thoroughly. And the layer of foam at the top was indicating the successful fermentation.
Fig.14. Transfer the supernatant to a new sanitized carboy by siphon.
Fig.15. At this time we check the gravity of the brew as well. The result indicates that the alcohol was increase during last two weeks. It tasted more like beer! Later we sent it back to Dr. Ebbole’s office, and keep it to carbonation for another one week.
16: One week later, we transfer brew from carboy to a keg by siphon, meanwhile part of them were bottled into glass bottles. Brew in keg were add the carbon dioxide by the pressure, and the bottle beer were add with the carbonation tablets. The beer will be ready to drink one week later.
17: Beer is ready! We did it!
Discussion: Although I am not a beer drinker, I really enjoy the experience of making it. It is really hard to imagine that we human use such small organism to help us produce this kind of specific product, and the mechanisms were just revealed at very recently. This demonstrate again that to know better about fungi will absolutely benefit we human being very much.
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