Something you need to understand I think...The airlock is NOT a magical fermentation tool or gauge. Your beer will ferment regardless of whether you use an airlock or not. ALL an airlock is is a vent, a valve to release excess co2. Nothing more. It's not even a gauge of fermentation.
All it is is some way to let gas escape from your beer so you don't blow the lid off your fermenter and paint your ceiling with beer. Lots of folks don't even use an airlock, some even just cover their fermenters with tin foil or plexiglass. Half my fermentations have no airlock activity whatsoever, regardless of buckets or carboys....In fact Northern brewer now has a little rubber valve that fits in the grommet hole and just lets excess co2 out. No need for an airlock (which is good for folks trying to do temp controlled fermentation in dorm fridges and stuff where there might not be room for either a tall airlock or a hose.
Which goes to show how inconsequential to the actual fermentation process they really are.
But you really really really need to get a hydrometer. You can't go by looks alone....I can't stress this enough.
Airlocks bubble or they don't it doesn't mean anything is wrong.
Half my beers NEVER have a bubbling airlock, but I've never had a fermentation not happen before.
Airlock bubbling and fermentation are not the same thing. You have to separate that from your mindset. Airlock bubbling can be a sign of fermentation, but not a good one, because the airlock will often blip or not blip for various other reasons...
If your airlock was bubbling and stopped---It doesn't mean fermentation has stopped.
If you airlock isn't bubbling, it doesn't mean your fermentation hasn't started....
If your airlock starts bubbling, it really doesn't matter.
If your airlock NEVER bubbles, it doesn't mean anything is wrong or right.
Your airlock is not a fermentation gauge, it is a VALVE to release excess co2. If it bubbles it is because it needs to, if it doesn't, it just means it doesn't need too...
Often an airlock will bubble if the fermenter has been disturbed in some way, like a change in temperature, change in atmospheric pressure, the cat brushing against it, opening it up to take a hydro reading, any number of things. The co2 has sat in stasis for a period of time, then it was disturbed so it is not longer at equilibrium with everything else now. And therefore it is blipping in your airlock...
Or you could indeed have fermentation happening, since maybe your fermentation was laggy and a change in temp restarted fermentation.
Airlock bubbling only tells you that co2 is coming out of the airlock, it is not telling you why. And there's various reasons. That's why it's not a good idea to equate airlock bubbling with fermentation...It could be because it is fermenting, or it could not be because of fermentation...so it's not a trustworthy tool.
And airlocks sometimes bubble or they don't. And airlock is a valve, a vent to release excess co2...NOT a fermentation gauge. It's important to make that distinction, or you'll be panicking everytime a an airlock doesn't bubble, or stops bubbling.
Fermentation is not always "dynamic," just because you don't SEE anything happening, doesn't mean that any-thing's wrong,, and also doesn't mean that the yeast are still not working diligently away, doing what they've been doing for over 4,000 years.
external visual cues like airlock bubbling and even krausen development are not as good or accurate indicator of what is happening "under the hood"....and why the one consistant indicator is gravity reading.
All krausens look different, even using the same yeast on different batches.
The amount of krausen can vary for whatever reason, it can come quick and depart quickly or it can linger long after fermentation is complete, and it all be normal.
or example, I had a wit beer that I pitched bottle harvested Hoegaarden yeast on Dec. 26th, LAST YEAR that STILL had a 2" krausen on it three weeks later. I took a grav reading and it had reached terminal gravity, 1.010. So the beer was done, but the krausen still lingered. I finally gently swirled the beer to knock it down, and let it settle for another week before I bottled it. I'm not normally a fan of knocking them down, and usually let it do it naturally.
But some yeasts are low flocculating, and may have a difficult time. I figured since mine was bottle harvested, and I had pitched the starter at high krausen, maybe it was "genetically mutated" with the flocculation "gene" off or something. So I gently swirled it and let it fall.
I brewed another batch with another mason jars worth of that yeast several months later and had the same thing happen.
Beligan wits are notoriously long krausening.
That's why it's fruitless to try to use those things as indicators, they aren't consistent from one batch to another....even with the same yeast.
That's why you need
to take a gravity reading to know how your fermentation is going, NOT go by airlocks, or size of krausen, or a calendar, the horoscope or the phases of the moon (those things in my mind are equally accurate).
The most important tool you can use is a hydrometer. It's the only way you will truly know when your beer is ready...airlock bubbles and other things are faulty.
The only way to truly know what is going on in your fermenter is with your hydrometer.
Like I said here in my blog, which I encourage you to read, Think evaluation before action
you sure as HELL wouldn't want a doctor to start cutting on you unless he used the proper diagnostic instuments like x-rays first, right? You wouldn't want him to just take a look in your eyes briefly and say "I'm cutting into your chest first thing in the morning." You would want them to use the right diagnostic tools
before the slice and dice, right? You'd cry malpractice, I would hope, if they didn't say they were sending you for an MRI and other things before going in....
So all you know is that your airlock is bubbling...NOT that your beer is fermenting or not.