What are the advantages and disadvantages of transferring to a secondary vs. a long primary?

Question

The conventional wisdom in homebrewing has been challenged in recent years. This wisdom held that a beer should be transferred from the primary fermentation vessel to a secondary one after 7-10 days. In recent years, many homebrewers have advocated for leaving the beer in primary until packaging, rather than racking to a secondary fermenter.

What are the advantages and disadvantages of the two methods? Are there limits to how long a beer should remain in primary, in the long primary scenario?

Answer 1

The biggest concern is autolysis of the yeast, which is when a yeast cell ruptures after it dies and releases off-flavors. This can take months to kick in, and may never even be an issue, but the potential is there for long conditioning. If I'm going to have a beer in a keg in <2 months, then I'll just keg it off of the primary. If I'm going to be doing any extended aging, then I'll rack it to a secondary to be safe. Plus, moving to a secondary for long conditioning frees up the primary to use again. For most beers though, a primary on its own is just fine.

Answer 2

There are pros and cons to each approach. In most cases, a long primary will be better than using a secondary fermentation vessel.

There are three distinct advantages to leaving the beer in primary, without using a secondary at all:

1. There is less risk of oxidation and infection since one transfer is eliminated.
2. You do not need an expensive carboy to use as a secondary.
3. It's less trouble.

There are also several disadvantages of performing a long primary fermentation:

1. If you are using plastic buckets, a very long primary (more than 4 weeks) will allow some oxygen to contact the beer. The plastic that the fermentation buckets are made of is slightly oxygen-permeable.
2. Since oxidation is not a concern, a longer aging in a glass container can produce a beer with greater clarity. This may also be possible with a primary performed in a glass carboy, except:
3. A long primary may lead to autolysis (yeast death, after which their guts spill into your brew.) The common consensus seems to be that autolysis flavors will only manifest after extremely long times in primary. Perhaps three months or more.

There are a few cases where a secondary vessel is advantageous:

1. You will need one if you are adding fruit to the beer. This is usually done by racking the beer on top of a pile of fruit or fruit puree in the secondary fermenter.
2. Some brewers prefer to dry-hop in a secondary fermenter (this can also be accomplished in a keg)

Answer 3

Interesting topic.

The only difference I have noticed between a long primary and transferring to a secondary is that in secondary conditioning I end up with a beer that has slightly less sediment. And this might just indicate that my beer siphoning skills are not yet perfected! I have noticed no obvious difference in brew quality between primary-only and secondary beer.

So, unless you really want to reduce the amount of sediment in bottles beer, I personally don't think the effort and risk of contamination in transferring to a secondary is worth it.

Interested to see what others say on this subject.