Ethanol fermentation or alcoholic fermentation is one of the most important parts of the brewing process, during this phase the beer receives its alcohol content. The brewing fermentation phase is one of the last phases of brewing beer; it happens after milling, mashing, lautering, boiling, whirlpooling and finally whirlpooling. During this phase a tank filled with liquid is aerated with oxygen. It is important to maintain the right amount of aeration, thus the right amount of oxygen levels, to not spoil the yeast. The amount of needed oxygen depends on the amount of liquid and bacteria in the tank. Eventually, the yeast converts the glucose in the wort to ethyl alcohol and carbon dioxide gas (CO2) is released. This CO2 can consequently be recovered (read more on CO2 recovery). Now, only filtering and bottling is left for the beer to be ready to drink.