We have one of the larger 1/4 inch auto-siphon tubes and racking cane.
When it gets about 3/4 done, the siphon starts sucking bubbles through the tube and makes a hissing noise.
The tip of the cane is fully submerged when this happens and the tube is full of beer the entire time.
It’s just that last short bit during the racking process that it starts blowing the bubbles through the tube and making the hissing noise.
I’m worried that I just oxidized 10 gallons of beer!
Anyone else experience this? Any idea why it would do this?