If/When to move to secondary fermentation

Question

Digression from What's the point of secondary fermentation?

What are the good rules of thumb for determining a. whether to use secondary fermentation at all and b. when to move from primary to secondary.

Preferably any rule of thumb should have both chemical and anecdotal rationale supporting it.

Answer 1

There are two things to consider when racking to secondary:

1. Wait for primary fermentation to finish. The common rule of thumb is to wait until the gravity of the beer doesn't change over the course of three days. This will indicate that the primary fermentation has completed. However, it's helpful to leave your beer in primary a little longer, even after fermentation has finished, to...

2. Allow the yeast to clean up byproducts in the beer. During reproduction and fermentation, the yeast product a number of byproducts that can contribute to off-flavors and instability in the beer. After fermentation is complete, the yeast clean up these byproducts. If you rack off of the yeast cake too early, the yeast won't get a chance to do this housekeeping, and you'll end up with undesirable compounds in your beer.

For most beers, I personally leave my beers in primary for no less than two weeks--often more for bigger beers--before racking to secondary or bottling. It's always better to leave the beer a little longer in the primary than to rack too early. Autolysis (the process by which yeast break down and die) isn't really a problem for homebrewers, unless you're keeping your beer on the yeast cake for many months to years.

Answer 2

From John Palmer in the "Ask the Experts" section of the AHA forum:

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.

So, the new rule of thumb: don’t rack a beer to a secondary, ever, unless you are going to conduct a secondary fermentation.

Answer 3

I've heard that beer can stay in the primary for several weeks, but I continue to rack to a secondary. I usually do it as soon as the head has died down and I'm pretty sure it's not going to flare up again in the carboy. I like to get the beer away from the grungy primary and get the primary cleaned. (I use a plastic pail for primary, and glass carboy for secondary.) And I like to do it quite early so that there will be plenty of CO2 still coming out of the beer to force the 02 out of the carboy. I usually let it sit a days or two, and then top it up with water.

I think there is still plenty enough yeast in suspension to do the clean-up mentioned by Jeff L.

I often bottle 2 or 3 weeks later. And though I know I probably don't need to use a secondary at all in those cases, I like to do it anyway. It's party aesthetic.

Answer 4

The current recommendation from homebrew experts John Palmer and Jamil Zainisheff is to never use a secondary unless you are doing an actual secondary fermentation...i.e., adding additional sugars or fruit. The previous ideas that you should move your beer off primary quickly came from commercial brewing examples. since we don't have fermentations on the same scale, that recommendation doesn't apply to us.

Answer 5

Using a secondary is a matter of preference for the brewer and the style of brew. While I highly recommend using a secondary it is not required.

You move to secondary after primary fermentation is done. This is usually determined by taking specific gravity readings and once they've been the same for 3 days primary fermentation is considered complete (~2+ weeks).

Secondary is used to clarify the beer and allow spent yeast and other materials to settle to the bottom for clearer beer and to prevent off tastes. It is also a good time to do things such as dry hop, add oak chips, or any other aging flavor. Secondary is usually done for around 1-2 weeks.

Answer 6

If you use a non-transparent plastic bucket or carboy for your primary, moving it to a transparent plastic or glass carboy allows you to see the clarity of the beer before bottling. You will be able to bottle your beer when the desired clarity is reached. In most cases, moving to a secondary is purely cosmetic.

Answer 7

In contrast to @Jeff L, I'd read in CJJ Berry that when brewing wine, it's advisable to rack off fairly early to prevent wine sitting on dead yeast and being contaminated by undesirable flavours.