There are different ways to “gauge” when your beer should be transferred from the primary fermenter to the secondary fermenter. We’ll discuss a couple of the ways to gauge, and we’d love to hear from you homebrewers out there if you use any of our suggested methods, or if you have a different way to tell when you should transfer your beer to a secondary fermenter. Keep in mind that these methods will vary from beer to beer.
Time the release of bubbles from the airlock. I’ve heard some people say when the airlock is down to releasing a bubble once every 20 seconds all that way up to once every minute. I’ve also heard to wait until bubbles have ceased completely, but these would seem that fermentation has completed and the beer should be bottled.
After a specified number of days. Some homebrewers like brewing on a schedule and prefer to work in 7 day increments for instance. Brew on a Saturday and put wort into a primary fermenter. On the following Saturday, transfer the beer to a secondary fermenter.
Transfer when gravity hits a certain level. Many kits will come with an anticipated final gravity, so transferring could take place when you are close to this figure. I prefer not to use this method because it requires opening the airlock or seal and puts your beer at risk for contamination
Another popular method and a solid way to gauge when to transfer to the secondary is by monitoring the bubbles and residue on the top of the beer. When the yeast is active, there will be a lot of residue on the surface, but as the yeast begins to die off, it and the residue will fall to the bottom of the fermenter. When the top is clear (or more clear) that can be a good time to transfer to the secondary.
Whatever method you prefer, one thing is for certain. Secondary fermentation will add clarity to your beer and will also give you a great opportunity to sneak a little sample and get a gravity reading. When moving beer from a primary to a secondary fermenter, it is also a good idea to transfer it into a smaller carboy (6.5 gallon to 5 gallon) because you don’t want your beer to oxidize, and keeping less airspace will help prevent this. Also, during primary fermentation, your beer may need the extra airspace for bubbles when the yeast is highly active.
View the video below and let us know whether you’d transfer this to a secondary with the airlock activity seen here. If you need to know more specifics about the beer, feel free to ask in the comments section.