Seems fermentation restarted in secondary

I am new to brewing. I brewed the caribou slobber as my first beer. After about three days in the primary, the foam on top had fallen and then the bubbling out of the air lock had stopped. I then transferred to secondary. After about two and a half weeks I checked the gravity by using a thief. I sanitized it before putting it in the fermenter. Since then it has started bubbling and a little foam is on the top. Not enough to cover the top, though. It has been a total of three weeks since brew day. Is this cause for concern?

It could very well be dissolved CO2 coming pout of solution and not fermentation at all. In the future, don’t xfer to secondary until at least a week or 2. Or do what most of us do and don’t use a secondary at all. Just leave the beer in primary for 3-4 weeks.

Denny is probably correct in thinking it is just trapped gas. I would wait a little longer in primary, even if most of the major work looks to be over.

On the other hand, late re-fermentation would be a sign of infection (but it would not just be a few bubbles - it would be pretty obvious). Keep an eye on it. If it continues like that for a while and does not clear out - it could be a problem. Otherwise you are fine.

Help me out here. In the secondary, is there little to no yeast left? I watched a video in where the person said the beer is taken out of the primary, off the settled yeast cake, and into a secondary with minimum head room. As I understand it, the goal is to have little to no yeast activity in the secondary? If so, how does that effect the natural carbonation in the bottling process? Or am I just completely off?

The goal of using a secondary is to get the beer off the dead yeast that has fallen to the bottom before they can break apart and cause off flavors to spread to your beer. Live yeast stays in suspension better, and even after many weeks of sitting, there will usually be plenty of live yeast still present floating about in the beer. Some people will say that using a secondary will result in clearer beer, or beer that clears faster. I personally have not found this to be the case, but depending on your equipment and process it may be true for some brewers.
The reason so many people have stopped using secondaries is that the quality of the yeast available to homebrewers has improved so much in recent years that there is little chance of having a large population of dead yeast present when you pitch. This means that the risk of those cells breaking apart and causing off flavors is pretty much negligible these days.
The fact that the yeast takes a long time to settle also means that there is still plenty of live cells floating around to carbonate the beer, even if the beer has been sitting for over a month. Somewhere around two months is where I might start to get worried and think about adding a little new yeast before bottling.

You can cold crash a beer for months and there will still be enough yeast in suspension to carb it.

You can cold crash a beer for months and there will still be enough yeast in suspension to carb it.[/quote][quote=“rebuiltcellars”][quote=“Matt_GA”]Help me out here. In the secondary, is there little to no yeast left? I watched a video in where the person said the beer is taken out of the primary, off the settled yeast cake, and into a secondary with minimum head room. As I understand it, the goal is to have little to no yeast activity in the secondary? If so, how does that effect the natural carbonation in the bottling process? Or am I just completely off?[/quote]
The goal of using a secondary is to get the beer off the dead yeast that has fallen to the bottom before they can break apart and cause off flavors to spread to your beer. Live yeast stays in suspension better, and even after many weeks of sitting, there will usually be plenty of live yeast still present floating about in the beer. Some people will say that using a secondary will result in clearer beer, or beer that clears faster. I personally have not found this to be the case, but depending on your equipment and process it may be true for some brewers.
The reason so many people have stopped using secondaries is that the quality of the yeast available to homebrewers has improved so much in recent years that there is little chance of having a large population of dead yeast present when you pitch. This means that the risk of those cells breaking apart and causing off flavors is pretty much negligible these days.
The fact that the yeast takes a long time to settle also means that there is still plenty of live cells floating around to carbonate the beer, even if the beer has been sitting for over a month. Somewhere around two months is where I might start to get worried and think about adding a little new yeast before bottling.[/quote]

Awesome. So today’s yeast are good enough to let sit in the primary the whole time, i.e. no secondary needed. That makes things a whole lot easier. Thanks!

Let me ask this then. So, by this logic, I can make a malty stout and let sit in the primary for a month, and be just fine? I plan on making something along these lines, and if I don’t truly have to transfer to a secondary, that would be wonderful!

No problem to do it like that.
BUT, even though yeast today is very good, you need to make sure you have enough of it and it is in good health when you pitch it. That’s why it is recommended you make a starter with liquid yeast. Check out MrMalty.com for some good reading on the subject.

So what are the signs of infection. Beer looks fine. No off colors or anything to cause concern. Just consistent bubbles from air lock.

One major point of concern would be if there are clear signs of fermentation when fermentation should be finished - ie if it is still going strong after 2 or 3 weeks.

Also, the beer would tend to stay cloudy and not clear out as normal.

Sniff test: would usually smell like a belgian’s ars (to varying degrees).

  • smell the stuff. Does it smell like normal beer? Are there any aromas that don’t seem right?

  • is it clear?

  • what is the gravity? If it is significantly lower than what you are expecting, it could mean that something has been eating the unfermentables (stuff that beer yeast cannot eat).

  • You can always taste some as well.