Airlock IS a good gauge of fermentation activity

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
B

bessieflames

Well-Known Member
Joined
Aug 4, 2011
Messages
98
Reaction score
0
Location
Denver
OK OK...before the hate messages start flying, let me explain. I always hear on this forum that you can't tell how your fermentation is proceeding by looking at the airlock. While this is good advice to give to noobs, I have found that it is not the case for me. I rely on gravity readings to determine when to keg, but for me, airlock activity gives me a good estimate of fermentation activity. I have taken gravity readings throughout the course of fermentations, and the airlock activity corresponds to the change in specific gravity. I know that I could easily go without a hydrometer by waiting until all bubbles stop and then waiting another week. I have completed probably 50 batches with all different types of yeast and it has always been the same.

Disclaimer: I use glass carboys, so there is much more room for variations due to leaks when using a bucket. Also, airlock activity won't tell if you have a stuck fermentation or missed your FG, but for 95% of fermentations, it is a good gauge of fermentation activity. It also makes sense. If you have no leaks, the CO2 output should closely match how much sugar the yeasties are eating. It isn't the end-all-be-all, but it is a good gauge. Ok--now rip me a new one.
 
Except that you can gets bubbles when the beer isn't actively fermenting... and it's possible to not get bubbles when the fermentation is actively chugging along. I'll agree it's reassuring to see the air lock bubbling away, but it doesn't mean a damn thing.
 
I have to agree, given good equipment, no air leaks, even barometric pressure, temp etc, airlock activity should line up directly with fermentation. After all, CO2 is being produced at the same time as etOH, and it has to get out somewhere. I think most people have a problem with new brewers freaking out that the airlock isn't bubbling. Ever since I started brewing, I have not once had a brew that didn't push the airlock, in multiple buckets and fermentation vessels. And yes, I take a look and if the airlock is bubbling, I assume all is well in primary. I think most people here are just tired of the typical "airlock not moving, should I dump it?" posts.

I'm with you: airlock bubbling = good, no airlock bubbling = may be a problem, check gravity (but that's never happened to me)
 
FWIW, I have had a brew that didn't have airlock activity and I got 80% attenuation. Probably a leak in an otherwise tight bucket. But I had no idea there was a leak at the time - it was a brand new bucket.

But also,things like allowing the carboy or bucket to increase in temperature will magically result in airlock activity. It's not fermentation. It's a result of CO2 being release because not as much CO2 can remain dissolved in higher temperature beer.

If you really know your system well and understand things like CO2 release, airlocks can be a really great indication. But in my opinion a more accurate statement is:

Airlock CAN BE a good gauge of fermentation activity
 
Perhaps a better statement that we could agree on would be:

"Airlock inactivity is not a reliable indication of fermentation problems."
 
DMartin said:
Perhaps a better statement that we could agree on would be:

"Airlock inactivity is not a reliable indication of fermentation problems."
Click to expand...

I would agree with that. I think the only airlock activity that I actually look at is the high fermentation bubbling that could be nothing else. When it slows to a bubble no more than every 20sec or so, I disregard any of it. Could be temperature changes, co2 slowly being released from the beer, or that low pressure system moving in.
 
DMartin said:
Perhaps a better statement that we could agree on would be:

"Airlock inactivity is not a reliable indication of fermentation problems."
Click to expand...

True. And this is why the advice is most often given to noobs. As far as barometric pressure and temperature change, this can add a few bubbles, but doesn't really compare with the amount of CO2 during fermentation. I readily admit that the main reason it works for me is that I use a carboy and have no leaks. A bucket will give different results.

Once you know your system and know that you don't have leaks, then it is a good gauge. It isn't the only thing you should rely on, but I disagree with the statement that it doesn't tell you anything. There is no way to ferment beer without producing CO2.

P.S. I have an airlock on an empty carboy and see maybe two bubbles per hour when there is a barometric change.
 
Noobs will then say, "Well, this one guy said that bubbling airlocks ARE a way to tell if fermentation is complete, so..."

This is why it's best to say that bubbling airlocks or non-bubbling airlocks don't mean anything. Experienced brewers don't need to listen to other people's advice, so what do they care if people say bubbles don't mean anything when they have enough experience to understand what the bubbles can tell them and what they cannot?
 
LandoLincoln said:
Noobs will then say, "Well, this one guy said that bubbling airlocks ARE a way to tell if fermentation is complete, so..."

This is why it's best to say that bubbling airlocks or non-bubbling airlocks don't mean anything. Experienced brewers don't need to listen to other people's advice, so what do they care if people say bubbles don't mean anything when they have enough experience to understand what the bubbles can tell them and what they cannot?
Click to expand...

It definitely is NOT a way to tell if fermentation is complete, and I made sure to make that distinction. It is a way to tell that fermentation is happening. It tells you nothing about if you hit your FG.
 
I have a pilsener that I'm fermenting at 46 degrees right now, it has a nice layer of krausen on top and I have yet to see one bubble. Before this I did a 1.105 scottish ale I fermented at 54, and although it dropped 80 points in 3 days it bubbled very little. But then when I brought it inside to 70 degrees it bubbled like mad over the next 2 days, even though the gravity stayed the same. Go figure.
 
By the way, I didn't post this to confuse noobs. I just suspected that most people look to their airlock to see what is happening in their fermentation vessle no matter how many times it is professed that it means nothing. I use it quite often as a gauge to tell when to take gravity readings.
 
Homercidal said:
Everything considered, airlock activity "may be" an indicator of fermentation activity, but only if certain criteria are met first.
Click to expand...

In my experience of about 50 brews, it has always been a good indicator. Not conclusive evidence, but good enough for me!
 
I think seeing and smelling my ales at high krausen is a lot more reassuring than a bubbling air lock. For carboys those things are easy, for a bucket not so much. It prefer relying on these things to reassure me that fermentation has begun without needing to bother with early hydrometer tests. Beyond that the only way you can be sure its done is to wait the proper amount of time.
 
I do think it's funny the responses I get saying that airlock activity means nothing, followed by an example of what the airlock has been doing. If it means nothing, why are you paying attention to it?
 
Living in the south with some pretty large barometric pressure shifts in thunderstorm season, I can almost predict a good thunder boomer coming if I have a batch bubbling. Approaching Low pressure causes bubbling to almost slow to a stop. works just like a pilgrim barometer (http://berryhilllimited.com/productimages/PW101x.jpg)

Although... I can use it as indication on when to take first gravity reading. I use about 2 or 3 yeasts on a regular basis for several years now, I pretty much know my time after pitching to take first reading, which "can" link up with airlock activity.
 
Airlock activity does not mean ANYTHING by itself. It has to be interpreted with an understanding of many other factors that are occurring during the airlock activity or have occurred before the airlock activity. I think that is what most people are saying.
 
I support the OP's position. I've never liked the strategy of implying to new brewers that airlock activity (or lack thereof) implies NOTHING about their fermentation, because it assumes they know nothing about (or don't care to learn anything about) the basic laws of physics.

Instead, there should just be a sticky that contains a short description of the ideal gas law and the different scenarios that can lead to pressure differentials (or lack thereof, e.g. leaks) between the inside of their carboy and the external atmosphere.

With that knowledge, they can solve problems with their fermentation systems and know more about how their fermentations are progressing under different conditions.
 
bessieflames said:
By the way, I didn't post this to confuse noobs. I just suspected that most people look to their airlock to see what is happening in their fermentation vessle no matter how many times it is professed that it means nothing. I use it quite often as a gauge to tell when to take gravity readings.
Click to expand...

This thread will confuse noobs.

Experienced brewers don't need to be told.

Therefore, this thread is not going to serve a good purpose.
 
I go by the airlock only, I only take a gravity reading when I am about to bottle. I keep my beer in primary for about 2 weeks after primary fermentation has finished - which I determine by watching the airlock. I figure if I didn't hit FG after 2 weeks after primary has wrapped up it's not because I didn't wait long enough, it's because I miscalculated or didn't use enough healthy yeast.

I just don't find it practical to take multiple gravity readings if I am keeping the beer in primary for 2-4 weeks.
 
bessieflames said:
Way to be a Negative Nancy, Bryan. If you don't like discussions about brewing, you are in the wrong furum.
Click to expand...

There is no discussion here though, its not a difficult concept nor does it actually provide any benefit to anyone. You just wanted to get some attention. Anyone that has brewed a few batches and is not retarded understands the airlock.

New brewers are the only ones who ask these questions. Your initial post is full of just poor information that has a lot of 'ifs' that require using the airlock as a good indicator of fermentation.

Do what works for you but think before you start stupid threads.
 
I think this thread should be useful to most new brewers. They want to learn like the rest of us, and many times I see people's responses to "my airlock isn't bubbling" threads is a curt response of "The airlock bubbling doesn't mean anything" with no explanation. Threads like these educate new brewers rather than unhelpfully inform them. I think it's good to get theories about why and how indicators like these should/should not be used.

PS. Holy sh*t people, calm down.
 
PoppinCaps said:
I think this thread should be useful to most new brewers. They want to learn like the rest of us, and many times I see people's responses to "my airlock isn't bubbling" threads is a curt response of "The airlock bubbling doesn't mean anything" with no explanation. Threads like these educate new brewers rather than unhelpfully inform them. I think it's good to get theories about why and how indicators like these should/should not be used.

PS. Holy sh*t people, calm down.
Click to expand...

Thank you. I think that it is more confusing to a new brewer to hear things like "experienced brewers know not to look at the airlock, only the hydrometer". That is simply not true. I use it, know its limitations, and I suspected that lots of other people use airlock activity to judge fermentation activity. Not the only judge, but the easiest by a long shot. Therefore, I think the thread has merit.

By the way, I have friends who don't own a hydrometer and go by airlock activity alone. The have made many many good batches of beer.
 
bessieflames said:
Thank you. I think that it is more confusing to a new brewer to hear things like "experienced brewers know not to look at the airlock, only the hydrometer". That is simply not true. I use it, know its limitations, and I suspected that lots of other people use airlock activity to judge fermentation activity. Not the only judge, but the easiest by a long shot. Therefore, I think the thread has merit.

By the way, I have friends who don't own a hydrometer and go by airlock activity alone. The have made many many good batches of beer.
Click to expand...

I agree with the first part of this post. I've used airlock activity as a primary indicator and a hydrometer as a quantitative measure for all of my fermentations. Since I use a glass carboy and only have ~0.5 - 1 gallon of headspace above the fermenting wort, I have airlock activity for every single one of my fermentations without fail. If I don't see airlock activity, I know something is awry.

As for the second paragraph, I wouldn't ever recommend this (which I know you're not, you're just giving an anecdote). I don't think there can be any argument that in the long run, you will be more informed and will make better beer by using a hydrometer.
 
Panic_Flowchart_2.png
 
bessieflames said:
By the way, I have friends who don't own a hydrometer and go by airlock activity alone.
Click to expand...

I highly doubt it. Most likely, they go by time and airlock activity combined. If they brewed a beer and 48 hours later they didn't see any bubbles, they wouldn't say, "Wow! I guess fermentation is done early!" and then begin to keg / bottle. Experience would tell them that they should wait longer before assuming that fermentation was complete. Noobs may not.
 
bottlebomber said:
I have a pilsener that I'm fermenting at 46 degrees right now, it has a nice layer of krausen on top and I have yet to see one bubble. Before this I did a 1.105 scottish ale I fermented at 54, and although it dropped 80 points in 3 days it bubbled very little. But then when I brought it inside to 70 degrees it bubbled like mad over the next 2 days, even though the gravity stayed the same. Go figure.
Click to expand...

This is a effect example of why a bubbling airlock means nada ! Co2 is held on a disolved suspension at lower temps at a higher rate. When said beer is moved to a warmer location the dissolved co2 cannot be held at the same rate in suspension there co2 comes out but there is no fermentation taking place. Trust a hydrometer not an airlock. Truly a airlock is no more than a trap to keep a one way street for outward exit only not a measuring tool. I will agree though that airlock activity is a good indicator but only to the extent something is happening.

Sent from my iPhone using HB Talk
 
I loved to watch my airlock. It was a good source of information and it was reassuring to see it bubbling away the day after pitching.

One time I waited and waited for the thing to start fermentation. After about 2 days I popped the top and took a whiff as I peeked inside. Instant nose burn.

See, the lid was not airtight, and so the CO2 took the easy way out through the leak, instead of out the airlock. Since I was somewhat experienced, I knew not to judge the fermentation by the airlock activity, but even I was on the edge of panic and re-pitching.

There are too many variables in equipment, time, and temp to safely say that all airlocks are going to be a useful source of fermentation information.

However, if you understand your equipment, the fermentation process, etc. then it can be useful as a means of fermentation activity.
 
ayoungrad said:
FWIW, I have had a brew that didn't have airlock activity and I got 80% attenuation. Probably a leak in an otherwise tight bucket. But I had no idea there was a leak at the time - it was a brand new bucket.

But also,things like allowing the carboy or bucket to increase in temperature will magically result in airlock activity. It's not fermentation. It's a result of CO2 being release because not as much CO2 can remain dissolved in higher temperature beer.

If you really know your system well and understand things like CO2 release, airlocks can be a really great indication. But in my opinion a more accurate statement is:

Airlock CAN BE a good gauge of fermentation activity
Click to expand...

Aschecte said:
This is a effect example of why a bubbling airlock means nada ! Co2 is held on a disolved suspension at lower temps at a higher rate. When said beer is moved to a warmer location the dissolved co2 cannot be held at the same rate in suspension there co2 comes out but there is no fermentation taking place. Trust a hydrometer not an airlock. Truly a airlock is no more than a trap to keep a one way street for outward exit only not a measuring tool. I will agree though that airlock activity is a good indicator but only to the extent something is happening.
Click to expand...

Homercidal said:
See, the lid was not airtight, and so the CO2 took the easy way out through the leak, instead of out the airlock. Since I was somewhat experienced, I knew not to judge the fermentation by the airlock activity, but even I was on the edge of panic and re-pitching.

There are too many variables in equipment, time, and temp to safely say that all airlocks are going to be a useful source of fermentation information.

However, if you understand your equipment, the fermentation process, etc. then it can be useful as a means of fermentation activity.
Click to expand...

PoppinCaps said:
See.... useful thread.
Click to expand...

Because the third time is the charm?
 
Homercidal said:
There are too many variables in equipment, time, and temp to safely say that all airlocks are going to be a useful source of fermentation information.

However, if you understand your equipment, the fermentation process, etc. then it can be useful as a means of fermentation activity.
Click to expand...

And that's why these threads are good. Definitely better than some where new brewers are emphatically told that AIRLOCK ACTIVITY MEANS NOTHING.

I once saw a thread where a very experienced brewer and frequent poster told a nervous new brewer that AT LEAST 50% of his fermentations never produced one bubble in the airlock. I asked him multiple times to please clarify to the new brewer the details of his fermentation vessels, since this observation surely indicates that he uses plastic buckets that are not that air-tight, but he abandoned the thread and didn't comment again.

Surely threads like that provide much more confusing information to the new brewer than a thread that stresses that you have to understand your equipment and the fermentation process before relying on airlock activity as an indicator of fermentation.
 
Sorry to get everyone riled up. I guess my setup is leak-free and my airlock activity tells me a lot about what is going on. Apparently not everyone has the same experience. I posted this because when I started brewing, I kept seeing this statement repeated over and over and it confused me because my airlock seemed to tell me every time EXACTLY what my yeast was doing. There was a day lag, then bubbles started slowly, day 2-4 was bubbling away, and then the next week they slowly died off. All of this advice to noobs directly contradicted what I had experienced and I wanted to see if anyone else had the same experience. It seems like most people have leaks/ temperature changes/ barometric changes more than I do. I stand corrected. I should have titled the thread "Airlock activity IS a good gauge of fermentation activity....for me).
 
bessieflames said:
Sorry to get everyone riled up. I guess my setup is leak-free and my airlock activity tells me a lot about what is going on. Apparently not everyone has the same experience. I posted this because when I started brewing, I kept seeing this statement repeated over and over and it confused me because my airlock seemed to tell me every time EXACTLY what my yeast was doing. There was a day lag, then bubbles started slowly, day 2-4 was bubbling away, and then the next week they slowly died off. All of this advice to noobs directly contradicted what I had experienced and I wanted to see if anyone else had the same experience. It seems like most people have leaks/ temperature changes/ barometric changes more than I do. I stand corrected. I should have titled the thread "Airlock activity IS a good gauge of fermentation activity....for me).
Click to expand...

Being lone of the offenders, I recognize I should also have been more precise (although I don't recall posting BDMA in the beginners' forum). For me it was exasperation fro the daily "Help, my beer is ruined!" threads that were invariably followed by "D'oh! Hydrometer FTW" about 48-60 hours later.

I still maintain that "airlock activity tells me EXACTLY what my yeast is doing" is equally misleading. All it really tells you is that your beer is off-gassing. But perhaps this has gotten to the point of splitting hairs,and is more trouble than help. So please, no more lectures on basic chemistry. I'll be careful in the future with my advice!
 
such a highly contentious issue... i have never experienced airlock failure, it's always been a good indicator for me. but for obvious reasons seen in this thread, i've never felt compelled to share that with anyone.
 

Similar threads

J
S05 Non Runner?
Replies
14
Views
581
Jack_0106
J
S
Anyone ever get a stuck fermentation with WLP300?
Replies
12
Views
717
jdauria
jdauria
Brooothru
Pressure Gauge Errors
Replies
9
Views
421
whoaru99
W
MaxStout
Preventing O2 ingress when cold-crashing for lagering - ideas?
2 3
Replies
81
Views
4K
jerrylotto
jerrylotto
R
Lager yeast question
2
Replies
52
Views
3K
redrocker652002
R

Latest posts

Back
Top