What is the purpose of secondary fermentation?

I'm not sure if this has been addressed but I'm gonna give it a shot

Ok. This is a brewbie question and a good chance for others to learn.

What is the point of secondary fermentation? If the primary has finished fermenting, on what does a secondary have to work?

Fillabong said:

I'm not sure if this has been addressed but I'm gonna give it a shot

Ok. This is a brewbie question and a good chance for others to learn.

What is the point of secondary fermentation? If the primary has finished fermenting, on what does a secondary have to work?

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This has been covered quite a few times...here are some of the threads.

https://www.homebrewtalk.com/forum/showthread.php?t=147&highlight=secondary+fermentation

https://www.homebrewtalk.com/forum/showthread.php?t=147&highlight=secondary+fermentation

Thanks for that link dude. If I have no sugar left in my brew and I bottle it up then my beer won't produce any CO2 will they?

Fillabong said:

Thanks for that link dude. If I have no sugar left in my brew and I bottle it up then my beer won't produce any CO2 will they?

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That's why you "prime" your beer with extra sugar before you bottle it.
There is enough yeast in the batch to eat that priming sugar and create CO2.

Ok I hear what you say orrelse. In a good brew I thought there isn't supposed to be too much yeast left. Enough to allow more a last fermention though. Hmm...I'll have to read more for sure. Thanks O

In a good brew I thought there isn't supposed to be too much yeast left.

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Actually this is only true in the wizz water sold by most commercial breweries. They have convinced us that their flavorless, thin, yellow water is the standard for beer. This is why they insist their beers are to be served so cold--shock your tastebuds so they can't discern how bad the beer really is.

In any homebrew you should have small amounts of yeast living and working all the way up until you drink it. This is part of the reason to decant homebrew (pour into a glass) to leave the yeast residue behind.

Your beer will be naturally carbonated by the action of the yeast on the priming sugar (or malt extract) added before bottling.

As for the purpose of secondary fermentation. It produces little in the way of alcoholic strength and the carbonation bleeds out through the air lock. The purpose is to refine the tastes of the beer. It will allow the yeast to work on the beer and improve the flavor.

I have made batches with identical ingredients and techniques, but put one through a secondary fermentation and bottled another right after initial fermentation, the difference was quite pronounced. You will produce a much better brew if you give it chance to secondary ferment.