What is the advantage of a second fermentor for home brewed beers?!
Some people also use a glass secondary because their primary bucket is either not completely airtight, or is made of a plastic that is not food grade. Food grade plastic is marked with either a number 1 (PET) or number 2 (HDPE) in the little triangular recycle symbol on the bottom. All other plastics are oxygen permeable, and will allow some oxygen to reach your brew if left long enough.
Third, it clears up your primary fermenter for another batch of brew!
RDWHAHB... ;)
Answers: There are a couple reasons for racking to secondary. First, it gets the brew off of the dead yeast that have settled to the bottom of your primary. The dead yeast will begin to break down (autolysis) after a couple weeks, and this can lead to off flavors in your brew. This also helps the brew clear, again, due to removing it from the yeast. This is especially important if you are lagering your brew.
Some people also use a glass secondary because their primary bucket is either not completely airtight, or is made of a plastic that is not food grade. Food grade plastic is marked with either a number 1 (PET) or number 2 (HDPE) in the little triangular recycle symbol on the bottom. All other plastics are oxygen permeable, and will allow some oxygen to reach your brew if left long enough.
Third, it clears up your primary fermenter for another batch of brew!
RDWHAHB... ;)
The beer taste better if it does not set on the sediment for the entire fermentation period. And you will have a clearer beer at botteling or kegging time.
Mitchell has a great answer, but I do need to add that it can add carbonation in for example open air brewed Lambics. It can also (when done properly) kick up the ABV a little.