Speidel airlock question

[RonObvious]

So I just received my first Speidel variable volume stainless steel tank and I have a question about the two-piece, screw-together airlock that comes with it. It appears that, when screwed together tightly, it will completely seal the unit, preventing air from entering and CO2 from leaving. If I screw it together only loosely, it would seem to allow gasses to exchange from both directions. In other words, it's either sealed or it isn't. There doesn't seem to be any way to allow CO2 to escape without the possibility of air entering, like traditional water filled airlocks do. Is that correct or am I missing something? And is this a problem? I know during active fermentation there will be positive pressure inside and a layer of CO2 over the wine, which should pretty much prevent air from contacting it. But when fermentation slows down, I'm a bit concerned that if the airlock is unscrewed a little, it might allow some air in.

 

[NorCal]

It should not be sealed, until there is no activity. Bad things can happen. I have seen screw tops that allow for breathable bungs / airlocks.

 

[RonObvious]

So in other words, keep it screwed on only lightly during fermentation, then tighten it for bulk aging?

 

[NorCal]

During the active AF, leaving it cracked is fine. During mlf, or when the wine is ridding itself of CO2, I'd have an airlock in place. When the wine is done producing CO2, in any amount, then a solid bung is appropriate.

 

[balatonwine]

Confused. This is a normal setup for a Speidel variable capacity tank during fermentation and degassing:

The orange plastic airlock you may need to buy separately. What you are calling the air lock is more likely just the attachment to seal the unit for long term aging and storage.

 

[stickman]

@RonObvious you should post a photo as there are different components depending on what you purchased.

The link is for assembly instructions.
https://morewinemaking.com/images/file.php?file_id=12271

 

[NorCal]

Mine is a fixed Spiedel

 

[NorCal]

fixed Spiedel

 

[balatonwine]

Mine is a fixed Spiedel

I would call that an HDPE tank with rubber bung inserted into the the top screw on port with a Spiedel two piece airlock attached. Not sure where the "fixed" part is. The orange sealing cap at the bottom also screws into this top screw port to seal the tank for long term storage and aging. I had to buy all my Spidel arilocks separately. As well as extra sealing caps. And I have quite a few such HDPE Spiedel tanks from 200 L on down (I prefer the screw top lid on the rectangular tanks):

 

[stickman]

I believe @NorCal is referring to fixed capacity.

 

[balatonwine]

I believe @NorCal is referring to fixed capacity.

Hm..... But the OP query is about a variable tank. And that is even not actually relevant. As the question was about the airlock.

 

[NorCal]

Yea, I was trying to describe my fixed capacity Spiedel vs. @RonObvious variable capacity and even though we have different tanks, the air locks are the same. I like your nicely worded description.

 

[RonObvious]

Thanks for the input all, I guess I should have included these pictures in my original post. The manual that came with the fermenter kept calling it an "airlock," but I'd call it more of a screw cap, myself. I may have answered my own question too... I found that a standard rubber bung (I think it's a #7) fits inside the inner collar. Which seems like the most sensible thing to do to me. Then, once fermentation is over, I'll take the rubber bung out and put the cap back on nice and tight.

 

[RonObvious]

By the way, the first two pictures (and the last) are looking at the top (outside) of the lid. The third picture is of the underside.

 

[Rmarr]

@RonObvious, just wondering if your gasket in you underside picture is on the bottom of the airlock? Morewine instructions say to put it on the top. Which way do you have it working?