What are the benefits of a secondary fermentation?

I saw this thread and it had me wondering.

link
http://forum.northernbrewer.com/viewtopic.php?f=1&t=111072

So what is the benefit of a secondary fermentation vs a longer primary fermentation? Are there brews that benefit from a secondary? Require a secondary? What are those benefits and do they risk the possibility of infection when racking to a 2nd carboy?

It’s my experience that cold-conditioning in a secondary fermentation vessel gives me a cleaner beer, and faster. When I bottle, there is a huge difference in the amount of yeast sediment in the bottle when doing secondary vs not, but of course this depends to some extent on how flocculent the yeast is and how long it’s in the primary.

Anytime you transfer, there will be a certain amount of sediment that makes it from one vessel to the next, and if you assume that this amount is a percentage that’s reasonably consistent, the above makes perfect sense.

As far as the risks of a secondary, they certainly do exist if you’re not careful. Personally, I worry about oxidation from the transfer process more than infection at that stage of the game, but either is possible depending on how you go about your work.

There are lots of folks who don’t secondary, and I’m sure their beers can be great. I would recommend that you compare the results vs. a longer primary for yourself and see how much difference it makes to your palate. Might be a bit difficult to do unless you do the comparison between identical or very similar beers, but if you can’t perceive a qualitative difference, there’s certainly no reason for the added risk and work.

Here’s part of what John Palmer had to say in teh Ask the Experts section of the AHA website. If you’re an AHA member you can read the whole thing there.

Therefore I, and Jamil and White Labs and Wyeast Labs, do not recommend racking to a secondary fermenter for ANY ale, except when conducting an actual second fermentation, such as adding fruit or souring. Racking to prevent autolysis is not necessary, and therefore the risk of oxidation is completely avoidable. Even lagers do not require racking to a second fermenter before lagering. With the right pitching rate, using fresh healthy yeast, and proper aeration of the wort prior to pitching, the fermentation of the beer will be complete within 3-8 days (bigger = longer). This time period includes the secondary or conditioning phase of fermentation when the yeast clean up acetaldehyde and diacetyl. The real purpose of lagering a beer is to use the colder temperatures to encourage the yeast to flocculate and promote the precipitation and sedimentation of microparticles and haze.

Since I keg, the recommendation for most ales would be to let it sit in primary for 6 weeks then keg? That would make my life easier. The longest primary I have done so far was only 3 weeks and it was a wheat beer so it was still hazy.

I am brewing the Innkeeper this week. I will leave that in primary for 4 weeks and then keg to see how it turns out.

[quote=“Denny”]With the right pitching rate, using fresh healthy yeast, and proper aeration of the wort prior to pitching, the fermentation of the beer will be complete within 3-8 days (bigger = longer). This time period includes the secondary or conditioning phase of fermentation when the yeast clean up acetaldehyde and diacetyl.[/quote]Completed fermentation, ready to keg and carb in 3-8 days? I think I might spring for a DO meter.

Thanks guys for the replies. I’m completely new to this hobby, so thought I would ask.

So ideally (everything equal like pitching rate, wort aeration, etc.), it’s better to go primary a bit longer, than transferring to a second vessel. I can understand if you’re adding fruit, etc., but for just basic run of the mill brewing, a longer primary is better?

I do have the How To Brew book by Palmer. I still have a bunch to read, but I love that book. Maybe a good experiment (if it hasn’t already been done) would be to do a comparison. Maybe take a simple recipe that requires a 2 stage ferment, split the ingredients to do two separate batches instead of one complete one. One goes through the normal 2 stage ferment, while the other batch stays in primary ferment longer.

I may try that myself one day.

Well, that’s what John says. It never works that way for me!