# Silicone Vented Bungs



## jumby (May 3, 2019)

Thoughts on silicone vented(breathable) bungs???? I don't see any downside to using these. I'm making the switch.


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## Johnd (May 3, 2019)

Made the switch years ago and haven’t looked back. Only time I use airlocks on carboys is during active fermentation.


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## CDrew (May 3, 2019)

Same here, after reading about them on this forum.

I have 2 sizes, 1 for carboys and a larger size for Intellitanks (1 1/2 inch sanitary fittings)

100% happy with them.

They are slippery though, especially when sanitized with Star San, so check your stoppers an hour after install and make sure they are still set in place. No issues when installed dry.


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## kuziwk (May 9, 2019)

I just bought a few to try from vintable, should have got more as the shipping was the most expensive part to Canada. Careful when inserting, I ended up sanitizing which made it slippery and forcing it in too far. Needless to say it's a good thing they are food grade as it now is at the bottom of the carboy. Careful when Inserting!


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## NorCal (May 9, 2019)

kuziwk said:


> I just bought a few to try from vintable, should have got more as the shipping was the most expensive part to Canada. Careful when inserting, I ended up sanitizing which made it slippery and forcing it in too far. Needless to say it's a good thing they are food grade as it now is at the bottom of the carboy. Careful when Inserting!


Use a plastic bag to get the bung out, it works


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## NorCal (May 9, 2019)

I like the breathable bungs that can be turned into a solid bung.


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## Rice_Guy (May 9, 2019)

NorCal said:


> I like the breathable bungs that can be turned into a solid bung.


I haven’t seen that part , , solid? , , valve like?
The breathable silicone at the local store has 4 or 5 vent holes. They leak when I apply a vacuum, , , as making a more robust headspace eliminator that will hold a vacuum for half a year, , , or sealing a flexible tank.


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## KevinL (May 9, 2019)

I have some and I love them. Go for it!


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## NorCal (May 9, 2019)

Rice_Guy said:


> I haven’t seen that part , , solid? , , valve like?
> The breathable silicone at the local store has 4 or 5 vent holes. They leak when I apply a vacuum, , , as making a more robust headspace eliminator that will hold a vacuum for half a year, , , or sealing a flexible tank.


There are some bungs that have a flap that sit on top of the bung (right) others that have a plunger that can be depressed when you are finished wanting it to be vented (left). I prefer the ones on the left, with better assurance of minimal O2 exposure when you are done with the venting activity. There is a hooded version of the bung for carboys.


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## kuziwk (May 9, 2019)

NorCal said:


> I like the breathable bungs that can be turned into a solid bung.


Yeah I heard about that, I'll be racking in another month so we'll see how it goes. I need to repair the bung once I get it out as I tried to pull on the top flap and apparently it's a two peice design (the top flap is not part of the bung), the top flap pulled right out...there is a little mushroom on the bottom that holds the flap to the bung.


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## Rice_Guy (May 9, 2019)

NorCal said:


> There are some bungs that have a flap that sit on top of the bung (right) others that have a plunger that can be depressed when you are finished wanting it to be vented (left). I prefer the ones on the left, with better assurance of minimal O2 exposure when you are done with the venting activity. There is a hooded version of the bung for carboys.
> View attachment 54501


Thanks!


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## cmason1957 (May 9, 2019)

I am a member of a Facebook group moderated by Daniel Pambianchi. He just wrote up a detailed scientific experiment he did between the older style bungs and the newer harder bungs. "My informal study looked at free SO2 consumption and oxygen levels at 3-month intervals for the same wine in the same type of carboy but with different bung types. Carboys with the older type of silicone performed as expected, i.e. little free SO2 consumption, low O2 levels."


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## stickman (May 9, 2019)

@cmason1957 Is there a link to the study or do you have to be a member to have access? It seems like there is a need to occasionally "myth bust" a topic of discussion, and Daniel Pambianchi has the resources and instrumentation to do it.


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## jumby (May 9, 2019)

cmason1957 said:


> I am a member of a Facebook group moderated by Daniel Pambianchi. He just wrote up a detailed scientific experiment he did between the older style bungs and the newer harder bungs. "My informal study looked at free SO2 consumption and oxygen levels at 3-month intervals for the same wine in the same type of carboy but with different bung types. Carboys with the older type of silicone performed as expected, i.e. little free SO2 consumption, low O2 levels."


How did the newer, vented bungs perform?


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## CDrew (May 10, 2019)

Regarding the plunger type silicone bungs, how do you know when to completely seal? I'm asking because I recently racked some fall 2018 Syrah that was still completely full of Co2. Meaning, I'm glad it wasn't sealed and hope it continues to off-gas. It's been under a silicone bung with a flap since October. The process is slower than I would have thought. I'm hoping 1 more vacuum racking prior to bottling will do it.

On another note, if your equipment includes sanitary fittings, you can completely seal with a cap if desired.


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## cmason1957 (May 10, 2019)

stickman said:


> @cmason1957 Is there a link to the study or do you have to be a member to have access? It seems like there is a need to occasionally "myth bust" a topic of discussion, and Daniel Pambianchi has the resources and instrumentation to do it.


I tried to make a link and gave up. It is so hard to do from inside Facebook. I believe you have to be a member of the group to see it. I do encourage anyone to join, I love when folks shoot off about something and Daniel gently corrects them with that science thing. Home winemaking is the name of the group.


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## cmason1957 (May 10, 2019)

jumby said:


> How did the newer, vented bungs perform?


I think all the harder bungs performed poorly.


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## kuziwk (May 10, 2019)

cmason1957 said:


> I think all the harder bungs performed poorly.


Which ones are the harder bungs? Do you have pictures comparing the two?


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## cmason1957 (May 10, 2019)

kuziwk said:


> Which ones are the harder bungs? Do you have pictures comparing the two?



I don't I am almost old school and only have the older Universal type bungs, which I believe are the "better" ones, in that they don't allow as much oxygen exchange and fit better into carboys. The ones that are not as good are similar to the ones pictured above.


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## kuziwk (May 10, 2019)

cmason1957 said:


> I don't I am almost old school and only have the older Universal type bungs, which I believe are the "better" ones, in that they don't allow as much oxygen exchange and fit better into carboys. The ones that are not as good are similar to the ones pictured above.


So I'm assuming the picture I attached is the new style? The old style is the solid rubber ones that are drilled out in the middle?


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## CDrew (May 10, 2019)

kuziwk said:


> So I'm assuming the picture I attached is the new style? The old style is the solid rubber ones that are drilled out in the middle?



Just me, but I really do not like the ones you show in your picture. Even traditional rubber air lock bungs can be problematic. Real silicone, seems to conform and seal best. Their only drawback is that they are slippery when wet.

These work well with air locks:
https://www.beveragefactory.com/hom...in-table-size-7-silicone-drilled-stopper.html


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## kuziwk (May 10, 2019)

CDrew said:


> Just me, but I really do not like the ones you show in your picture. Even traditional rubber air lock bungs can be problematic. Real silicone, seems to conform and seal best. Their only drawback is that they are slippery when wet.
> 
> These work well with air locks:
> https://www.beveragefactory.com/hom...in-table-size-7-silicone-drilled-stopper.html



That's what she said , i just placed an order for two vented bungs from vin table to try them. I'm typically using the standard hard ones I posted but generally only for 3-6 months. The vented ones are for the carboys going longer than that. I Will be testing for Sulphites pretty soon here...just waiting for my chemicals to arrive, so I can conduct my own tests. I don't think a little bit of oxygen is a bad thing as it builds structure in the wine, it's beneficial in barrel aging and is really the only difference to what we do in air tight glass compared to what commerical wineries do. So perhaps the added oxygen with the new bungs/air lock, some added tannin complex and oak cubes will be a good alternative to barrel aging. The only problem is we than need to make sure sulphite levels are adequate. From what I understand this is a major problem with oak barrels anyways forcing us to do testing.


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## vacuumpumpman (May 11, 2019)

cmason1957 said:


> I tried to make a link and gave up. It is so hard to do from inside Facebook. I believe you have to be a member of the group to see it. I do encourage anyone to join, I love when folks shoot off about something and Daniel gently corrects them with that science thing. Home winemaking is the name of the group.



I got ahold of Daniel and got a link for what you were looking for = 

https://techniquesinhomewinemaking.com/attachments/File/Coravin Performance Study Paper v0.1.pdf

I hope this helps -


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## sour_grapes (May 11, 2019)

vacuumpumpman said:


> I got ahold of Daniel and got a link for what you were looking for =
> 
> https://techniquesinhomewinemaking.com/attachments/File/Coravin Performance Study Paper v0.1.pdf
> 
> I hope this helps -



I don't think this study addresses what is being discussed in this thread (viz., silicone bungs for carboys). Perhaps he misunderstood what you were asking about?


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## vacuumpumpman (May 14, 2019)

sour_grapes said:


> I don't think this study addresses what is being discussed in this thread (viz., silicone bungs for carboys). Perhaps he misunderstood what you were asking about?




Here I copied and pasted it off of facebook = 
*Daniel Pambianchi*
April 17 at 9:04 AM
After a 9-month watch period, I now have conclusive evidence that "grab ring" type bungs (TOP picture) allow much more oxygen into carboys than the common silicone bungs. Now, I'm suspecting the new-type, hard-silicone bungs (BOTTOM picture) may have the same issue.

My informal study looked at free SO2 consumption and oxygen levels at 3-month intervals for the same wine in the same type of carboy but with different bung types. Carboys with the older type of silicone performed as expected, i.e. little free SO2 consumption, low O2 levels.

P.S. Yes, I know, the bungs are not inserted fully. I am in the process of sampling and analyzing the wines.


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## kuziwk (May 15, 2019)

vacuumpumpman said:


> Here I copied and pasted it off of facebook =
> *Daniel Pambianchi*
> April 17 at 9:04 AM
> After a 9-month watch period, I now have conclusive evidence that "grab ring" type bungs (TOP picture) allow much more oxygen into carboys than the common silicone bungs. Now, I'm suspecting the new-type, hard-silicone bungs (BOTTOM picture) may have the same issue.
> ...




So which bungs would have the grab ring or be considered the hard silicone?

It's these ones?


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## cmason1957 (May 15, 2019)

kuziwk said:


> So which bungs would have the grab ring or be considered the hard silicone?
> 
> It's these ones?


No, those are the ones considered soft.


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## Johnd (May 15, 2019)

cmason1957 said:


> No, those are the ones considered soft.



I read that whole post on FB and it’s confusing. The ones you just called “soft” are (to me) the “old kind” and are way harder than the white vented bungs I use, they lose much pliability in my chilled cellar environment and seal poorly. The white, soft ones seal way better in my carboys and barrels and maintain their pliability even at lower temps. 

In any case, and with no disrespect to the study, the soft, white, pliable ones remain my choice, I’ve never had any kind of issue using them with short or long term storage in carboys or barrels.


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## SethF (May 15, 2019)

Johnd said:


> I read that whole post on FB and it’s confusing. The ones you just called “soft” are (to me) the “old kind” and are way harder than the white vented bungs I use, they lose much pliability in my chilled cellar environment and seal poorly. The white, soft ones seal way better in my carboys and barrels and maintain their pliability even at lower temps.
> 
> In any case, and with no disrespect to the study, the soft, white, pliable ones remain my choice, I’ve never had any kind of issue using them with short or long term storage in carboys or barrels.


John- Can you please provide a link to the ones you prefer?


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## stickman (May 15, 2019)

I was also a little confused which is why I was looking for more information. He refers to all of the tested bungs as being silicone, yet many bungs on the market are not silicone, not sure if he is just using the term loosely, or if he verified that the bungs tested are silicone. The one in his top photo looks like this silicone carboy bung from Morewine https://morewinemaking.com/products/silicone-bung-solid-carboy.html

I am also currently using silicone bungs on my two demijohns and haven't noticed any issues, though I'm not confident that means much from a technical viewpoint. I guess if the wine still tastes good there's no need to worry. I have noticed that many wineries are still using silicone bungs on their barrels, though I have seen some using glass bungs.

It is well known that silicone is one of the most gas permeable elastomers on the market, I assume that's why he is conducting the test. There is an old study from Betterbottle that indicated silicone bungs were more permeable than the standard rubber bungs. http://www.better-bottle.com/pdf/ClosuresOxygenPassageStudy.pdf


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## kuziwk (May 15, 2019)

I'm welcoming the so2 to leak out and let a bit of oxygen in, I accidentally added double the SO2 in two kits. If I leave it until Christmas or maybe longer with the leaky bungs I'm sure it will be fine.

So we are assuming silicone bungs are more permeable? What about the vented silicone bungs from morewine/ vintable?


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## Johnd (May 15, 2019)

SethF said:


> John- Can you please provide a link to the ones you prefer?



These are they:

https://www.morebeer.com/products/c...MIqonlhsSe4gIVSLnACh1_WwULEAQYBCABEgKFkPD_BwE


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## jsbeckton (May 16, 2019)

Love these. This was a good reminder so I just ordered 5 more!


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## skyfire322 (May 19, 2019)

Johnd said:


> These are they:
> 
> https://www.morebeer.com/products/c...MIqonlhsSe4gIVSLnACh1_WwULEAQYBCABEgKFkPD_BwE



I ended up getting three of these. So much better than using an airlock! I store my carboys in a cooler bag for bulk-aging and the airlock would keep falling off because it was just a bit too tall. I placed a strip of electrical tape over the top of it just to make sure it doesn't pop off and haven't ran into any issues since!


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## kuziwk (May 24, 2019)

skyfire322 said:


> I ended up getting three of these. So much better than using an airlock! I store my carboys in a cooler bag for bulk-aging and the airlock would keep falling off because it was just a bit too tall. I placed a strip of electrical tape over the top of it just to make sure it doesn't pop off and haven't ran into any issues since!


I keep a roll of electrical tape in the wine room for this very reason. When the airlock bungs are wet they rarely stay in


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## andrewmaixner (Jun 1, 2019)

I'm coming at this from moreso from a beer/mead perspective (I make some higher-end kit wines, but nothing advanced, just EM/nutrient/yeast improvements), but here's a relevant study which I've read in the past about O2 permeability of various bung materials. 
The main takeaway was that old-fashioned RUBBER was the best, and that airlocks let through a *lot *of oxygen. 
https://www.mocon.com/assets/documents/PPS_Article_highq.pdf

I'd love to see a similar study on the new silicone self-venting bungs -- I just can't seem to get myself to trust them, as a hands-on look at the store didn't inspire confidence. But I don't know what model it was, maybe not the 'good' ones.


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## kuziwk (Feb 19, 2020)

Resurrecting this thread, have any new studies come out yet? I tend to use standard air lock with the flange type bungs for a year of aging, although I did buy some drilled rubber bungs as well as a few vented silicone bungs. Every time I rack I tend to add 1/4 tsp or 1.2 Grams anyways since testing every racking would be a huge pain and also wastes precious wine, lol. Has anyone ever run into trouble racking and adding every 3-4 months and not having enough sulfite?

I did just bottle an early RJS international grand crew where I tested the sulfite level before bottling and they were on the verge of being dangerously low at 14PPM. I racked from the primary, added 4G sulfites and used my stirring rod to carefully degas as always, than added the clearing agents. Rack again in three weeks adding some oak. Racked again in two months and tested at 14PPM before racking to bottle. Usually i would wait three months instead of two but i needed the carboy for my high end kits without clearing agents. In any case i used a standard S airlock and lipped & hollow universal carboy bung.


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## ZebraB (Feb 20, 2020)

This isn't a new study but found it interesting. This article states that contact lenses are made of silicone because of their oxygen diffusion.

http://www.better-bottle.com/pdf/ClosuresOxygenPassageStudy.pdf


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## kuziwk (Feb 20, 2020)

ZebraB said:


> This isn't a new study but found it interesting. This article states that contact lenses are made of silicone because of their oxygen diffusion.
> 
> http://www.better-bottle.com/pdf/ClosuresOxygenPassageStudy.pdf


Just posted a new thread, I did an informal experiment and found that the silicone vented bungs perform better than the hollow rubber, lipped bung and airlock. It seems that water would be more permeable than silicone which makes sense since it’s less dense.


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