Secondary fermentor?

What purose or benefits does using a secondary fermentor have. Or what is the reasoning behind using one and when should a secondary fermentor be used.

The purpose of a clearing tank is obvious. Homebrewers insist on calling them secondary fermentors, which confuses people. I can think of only two commercial brews that undergo secondary fermentation (I'm not classifying bottle conditioning as a secondary fermentation here). And the only homebrew I make that goes into a secondary is my barleywine, although there are other styles when you add fermentables and do a second ferment.

A clearing tank is used to let the ale settle. It can also be used for dry hopping.

As David_42 said, it is really a clearing tank. You can leave your beer safely in it for months if necessary before bottling or kegging.

However, it has another very useful purpose. It frees up the primary fermenter so you can get on with a second brew. You don't want to leave the beer in the primary for too long or it can develop off flavors.

-a.

So baisicly its just a clearing tank and a place to let it age and settle to avoid any bad flavors from the yeast.

yes that is pretty much correct. It is mainly used to get the wort off the trub at the bottom that overtime can give off bad flavors for aging...