Are all airlocks created equal?

[NorCal]

An observation, which made me question the use of the three piece or S shaped airlocks.

I have a 60 gallon French oak barrel that I love. When I go to top up the barrel after 3 weeks or so and pull the solid silicon bung off the barrel there is a large sucking sound as the evaporated water has created a vacuum in the barrel.

This made me think.

1. if I used a three piece or S shaped, add water type of airlock, would that vacuum in the barrel still be there? Would fresh outside oxygen pass the water in the airlock and fill the void?

2. even with the weekly change in temperature of a carboy, does that pushing air out of the water based airlocks and then suck fresh oxygen right back in when it is cooler?

I suspect the answer is yes, but it must not be significant. Looking forward to @sour_grapes and other’s thoughts.

 

[Ajmassa]

Never really put much thought into this. But that negative pressure when popping a bung on a is certainly reassuring.

I notice this with certain types of the waterless vented bungs as well. The carboy style I don’t. I suppose they allow pressure to escape more easily. But I get that “pop” with both the barrel and the demijohn vented bungs. Even if S style and 3piece style airlocks counter that ‘vacuum’ with an insignificant amount of air intake, still would prefer having that natural vacuum on aging wine.
And not all bungs are created equally! Here are the vented types I use.

The vented barrel bung

Vented demijohn bung

And vented carboy bung

 

[sour_grapes]

An observation, which made me question the use of the three piece or S shaped airlocks.

I have a 60 gallon French oak barrel that I love. When I go to top up the barrel after 3 weeks or so and pull the solid silicon bung off the barrel there is a large sucking sound as the evaporated water has created a vacuum in the barrel.

This made me think.

1. if I used a three piece or S shaped, add water type of airlock, would that vacuum in the barrel still be there? Would fresh outside oxygen pass the water in the airlock and fill the void?

2. even with the weekly change in temperature of a carboy, does that pushing air out of the water based airlocks and then suck fresh oxygen right back in when it is cooler?

I suspect the answer is yes, but it must not be significant. Looking forward to @sour_grapes and other’s thoughts.

Thanks for the vote of confidence. I don't have a lot to say on the matter, but I can say a coupla things.

Regarding your first question, for an S-shaped airlock, it can certainly pass bubbles in either direction. (I have never used a 3-piece, and am unsure about them passing gas the other direction.) So, I am pretty sure that you would NOT get the vacuum in a barrel with an S-shaped airlock.

Regarding your second question. In a properly topped up carboy, I didn't/don't think there is enough change in volume with reasonable temperature swings to pass a bubble, IME. However, I just did a quick calculation with an online calculator, and for a 10 degF swing, the wine itself changes by ~25 mL. And there also is the (much smaller) headspace, but it has a larger coefficient of expansion, so a 50 mL volume would have a ~1 mL change. So maybe I am wrong and you do get enough delta-Volume to cause a bubble with a 10 deg swing.

What I always wonder about is the simple transport of oxygen through the liquid in the airlock. Let's say you rack your wine into a carboy, and it starts out saturated with O2. Let's further assume that this O2 reacts and gets bound up (SO2, tannins...). There is nothing stopping additional O2 from diffusing through the liquid in your airlock (except maybe sulfites in your airlock!). However, I have not done the calculation to see how fast more O2 would be transported through, say, water. I generally give a shot of sulfites to my airlocks from time to time.

 

[Johnd]

I also get that same action sometimes when pulling the solid bung from my larger barrels, and have had similar thoughts. Some of that action may be actually caused by the process of removing the bung creating the vacuum, but probably not all of it. In the end, I decided that if the barrel wants to have a slight vacuum in it, so be it. The worst that could happen is that some outside air gets pulled through the wood, in controlled amounts, and is just micro oxygenation, which is why my wine is in the barrel in the first place. Better than having bubbles pulled through an airlock in my opinion.

 

[Boatboy24]

I've been using a solid stopper on one of my barrels, and I find the 'suck sound' somewhat reassuring. No noticeable difference in evaporation, BTW. I've been trying out waterless, vented bungs on a few of my carboys and while not always, will often get the same suck. For wines that I'm confident are degassed, I've been trying out solid bungs on carboys too. One thing I do like about the S shaped airlocks is that you can just look at the water levels on each side to gauge if you have a good seal. Sometimes, even a good seal will show even water levels, but not always. Downside is you have to watch water levels and keep sulfite (or something else) in them to inhibit growth of bad 'stuff'.

 

[mainshipfred]

The problem I have with solid stoppers on carboys is I have a problem with them blowing off even with fully degassed wine. It only happens on certain ones and I have yet to figure out the common denominator. With the S shaped air locks some show positive pressure, some negative and some neutral and again no common denominator that I'm aware of.

 

[btom2004]

Solid plugs are used on barrels, as you would be aging the wine there for a much extended period of time. Usually the wine is finished, with nothing further to do, but let it age. Where as air locks are used on carboys, to allow the gases to continusly escape during storage. This degases the wine while it ages. The air locks are time savers. The wine gets degased much faster, then wine aged in barreles. Also it's easier to rerack, back sweeten, or add other ingredients or favor to your wine. Any addition may or may not trigger fermentation, which would blow the solid bung off. Please note that air is not a friend to wine, it could spoil it. Thus if you open a bung or remove air locks you are letting air into the wine. That's not good. There is no reason you should be removing bungs or air locks unless you are about to rerack to filter, clear or bottle wine. Or perhaps to add a bit more sulphite.

That sound that you love to hear when you removed the solid bung, ment your barrel was sealed correctly. The gases caused by aging were protecting your wine from any outside air entering to spoil your wine. So when you pop one open, you let the protected gases out and the destructive air in.

 

[stickman]

I tend to agree with the concept that for long term aging, a barrel should develop a vacuum if properly sealed. When I was using barrels in the past, I would switch over to a solid silicone bung a few months after malolactic completion. I also rotated the barrel to the 2 o'clock position alternating direction every few months, not sure if it really made any difference, but sometimes between toppings you can get significant headspace, so I felt it was important to keep the bung stave wet.

Oxygen finds its way into barrels and even carboys one way or another, leaks around the bung and airlock stem are always possible, plastic airlocks and silicone bungs are permeable, temperature swings can bring in oxygen as previously mentioned, it's really the reason why experience has shown that everything needs to be topped up into the neck to reduce the exposed surface.

Next time you open a carboy that has been aging for a while, pull a sample from the top 1 inch, and compare to a sample from mid-carboy, and also compare to a sample pulled from near the lees (if there are any), you'll probably find 3 different wines and that oxidation is occurring from the top down (as long as the storage area has fairly constant temperature, which reduces wine bulk movement).

Unless you have major leaks and/or large temperature swings, as long as you are topped up, most of this stuff is of minor importance, and the wine turns out just fine.

 

[Johnd]

I would have thought that Brownian Motion would work against a layering effect like this, but I’ve never sampled my wine in that fashion.

 

[BMarNJ]

The problem I have with solid stoppers on carboys is I have a problem with them blowing off even with fully degassed wine. It only happens on certain ones and I have yet to figure out the common denominator. With the S shaped air locks some show positive pressure, some negative and some neutral and again no common denominator that I'm aware of.

The other day I racked my 6 month old cabernet. After that, I couldnt keep the solid silicone bung from popping out, so I switched back to an airlock. In the previous 3 months, the solid bung never popped. I can’t figure it out, but the temp is probably a little warmer now in the basement since the heat kicks on, and maybe I topped it up a little higher. Do you think I have an issue created from racking? I added sulfite when I racked. Thanks.

 

[stickman]

What did you top up with?

 

[Johnd]

The other day I racked my 6 month old cabernet. After that, I couldnt keep the solid silicone bung from popping out, so I switched back to an airlock. In the previous 3 months, the solid bung never popped. I can’t figure it out, but the temp is probably a little warmer now in the basement since the heat kicks on, and maybe I topped it up a little higher. Do you think I have an issue created from racking? I added sulfite when I racked. Thanks.

Perhaps the action from racking has prompted your wine to release some CO2. I typically don't put solid bungs on any of my wines except those that are in barrels, just leave the airlock on there and let it do its thing!

 

[BMarNJ]

What did you top up with?

Some purchased cabernet that I was drinking that night.

 

[JoP]

The problem I have with solid stoppers on carboys is I have a problem with them blowing off even with fully degassed wine. It only happens on certain ones and I have yet to figure out the common denominator. With the S shaped air locks some show positive pressure, some negative and some neutral and again no common denominator that I'm aware of.

I have the same problem with the three piece airlocks on carboys; they pop out easily especially if the inside of the mouth is wet.

This happens on all smooth mouth carboys made in China, but the Italian carboys have a rough surface inside the mouth and these rarely have this problem.

The Italian carboys are made of thicker glass and claimed to be of a more uniform thickness, but they are almost double the price.

To prevent oxidation due to the inevitable exposure to oxygen, I top off all my vessels with Argon.

Cheers

 

[BMarNJ]

Perhaps the action from racking has prompted your wine to release some CO2. I typically don't put solid bungs on any of my wines except those that are in barrels, just leave the airlock on there and let it do its thing!

I switched to the solid because I was following the instructions from More Wine.. but I think you’re right. Or else I’ll give it a few days and try the solid again after it settles down.

 

[jburtner]

I have the same problem with the three piece airlocks on carboys; they pop out easily especially if the inside of the mouth is wet.

This happens on all smooth mouth carboys made in China, but the Italian carboys have a rough surface inside the mouth and these rarely have this problem.

The Italian carboys are made of thicker glass and claimed to be of a more uniform thickness, but they are almost double the price.

To prevent oxidation due to the inevitable exposure to oxygen, I top off all my vessels with Argon.

Cheers

I've got this issue on several of my carboys. I wonder if roughing it up in the inside of the neck with a little emory paper would help?

Cheers,
johann

 

[Johnd]

I've got this issue on several of my carboys. I wonder if roughing it up in the inside of the neck with a little emory paper would help?

Cheers,
johann

The other thing that you can try is drying off the bung and the inside neck of the carboy, then twisting the bung as you push it down in place. Even my vented bungs will pop up if the neck / bung is wet, due to the slippery nature of the silicone and taper on the bung. A reproduction from the past: "Nobody likes a wet, slippery bung hole."

 

[Ajmassa]

The other thing that you can try is drying off the bung and the inside neck of the carboy, then twisting the bung as you push it down in place. Even my vented bungs will pop up if the neck / bung is wet, due to the slippery nature of the silicone and taper on the bung. A reproduction from the past: "Nobody likes a wet, slippery bung hole."

The twist definitely works when they’re stubborn. Ya gotta cork screw that sucker into that bunghole. Just a little extra convincing helps if they aren’t into it at first.

However I do have one vessel that refuses to accept it in the bunghole<- and it’s not the wife!

*i really do lol. It’s a 34L demijohn which has an odd sized opening and taper. Smaller than large demis and PET, —closer to #9 barrel bung but all depends on the taper.
Only the solid rubber style bungs stay in that. The friction of the rubber holds it down. (Not sure what type of rubber that is) But any type of silicon refuses to hold (nothing to do with pressure)

The universal style silicon bungs have similar friction, however no size fits the damn thing. I would go and check my wine and notice the bung would be sitting loose. Maybe sealed maybe not. Still trying to find ideal stoppers for it.

 

[stickman]

I've used Velcro ties around the neck and over the top to hold the bungs, only one narrow strip over the top so if pressure gets high enough, the bung will tilt and release the pressure; the last thing you want to see when you come down to the cellar is a ruptured 54L demijohn.

 

[jburtner]

I've tried different things with both S shaped and 3 piece airlocks and on certain carboys the bung always slips up. Maybe a couple wraps of 1" teflon tape would help in those cases also.

Cheers!
-johann