So why is my auto-siphon now injecting air into my beer?

[FTG-05]

I have a standard NB auto-siphon sized for 3/8" tubing. I just replaced the tubing since I found some mold in the original ones.

Now, when I siphon, air is injected into my beer when I siphon from the fermenter into my bottling bucket. The air is coming out of solution right at the end of the racking cane exit.

What's causing this and what can I do to stop it? I don't recall it being a problem with the original 3/8" tubing. I hope I haven't ruined the one beer I've bottled since I noticed this.

Help!

Thanks,

 

[Jayhem]

perhaps it's not making a strong air-tight seal where the new tubing attaches to the cane? you can put a hose clamp or zip tie on it to see if that helps.

 

[MTate37]

I've had this same issue myself. The first time it occurred I believe that the clamp holding the tube to the racking cane wasn't tight enough. As soon as I tightened the clamp the air issue went away.

When the clamp is as tight as it will go and this happens, I'll lift up on the first few inches of the tube coming off of the racking cane and the bubbles will go away pretty quickly. I don't know the reason for this, but my LHBS recommended it and it works. Maybe it slows the flow coming out of the racking cane just enough so that the liquid can fill the space where the bubbles are. Try it with water before you rack again. I've had one terribly bubbly racking situation and it was really frustrating, so I always practice a few times with sanitizer just to make sure I'm not going to have an issue.

If these don't work for you, maybe a more experienced brewer than myself will have some other ideas. I have also heard that the spot where the racking cane ends can act as a nucleation site and the bubbles that you see there are just CO2 that is coming out of solution.

 

[the_trout]

I had the same issue. The bubbles were forming where the tubing meets the racking cane. It was a bad seal even though it looked fine. I resealed it by heating the tubing in some hot water so it became more pliable. This allowed for deeper penetration of the cane into the tube... (insert joke here). Anyways, the air bubbles went away and I've had no problems since.

 

[GarageDweller]

squeeze the small air bubble out while the beer is racking through it. i have had the same problem before, all i did was squeeze the tubing right where it was connecting to the cane (which is also where the air bubble was) and the bubble went away. it doesn't always happen, but i am on the lookout for it everytime i use the auto siphon now. don't want to oxidize the beer this late in the game (well, ever really, but it sucks to come this far and have problems transferring).
good luck with it

 

[homebrewdad]

Guys, you're all making this too hard. Most auto siphons do this (or get to this stage) - it's really tough to keep a perfect seal.

Provided that you do have a tightly fitting hose, there's only one other spot that the auto siphon tends to leak - around the plunger itself.

To remedy this, pour a little sanitized water down the tube on top of your plunger. The vacuum is restored, and the bubbles go away. The worst you get is a few drops of sanitized water in your beer.

 

[pwkblue]

Guys, you're all making this too hard. Most auto siphons do this (or get to this stage) - it's really tough to keep a perfect seal.

Provided that you do have a tightly fitting hose, there's only one other spot that the auto siphon tends to leak - around the plunger itself.

To remedy this, pour a little sanitized water down the tube on top of your plunger. The vacuum is restored, and the bubbles go away. The worst you get is a few drops of sanitized water in your beer.

the most likely air leak source is from around the plunger gasket...it will be worse if the fluid intake is blocked by trub, hops etc. BUT the bubbles you see at the cane/tube junction may just be co2 in solution being released by the turbulence. Put a kink in your tube and you will see the same thing

 

[FTG-05]

Thanks guys. I racked the last of my Skeeter Pee this afternoon and I didn't have a problem. This time I installed a small hose clamp at the hose/siphon junction and no air or bubbles.

Much happier camper!!!

Thanks!!!

 

[XPLSV]

It is, indeed, air entering at the top of the racking cane from the tubing-cane juncture. I have used the small worm clamp to stop this issue with some thick wall tubing on one of my racking canes. On another racking cane, I have used thin wall tubing and the fit is tight enough that I get no air seepage. In fact, I cut that tubing off the cane after each use.