I've used a 1 1/4 OD blow off tube before and it worked great with no issue. My next batch (nut brown ale) pumped out a decent amount of foam into my elevated sanitized jug of water (star san). I went to rack it into the secondary, and as I pulled the blow off hose out of the sanitized water I heard some splashing in the carboy. The light was off in the room and the carboy was covered so I didn't actually see the water going into the carboy. I don't think that it was very much (maybe a cup) but still somewhat concerned. The temperature in the closet is a steady 66 degrees F. I don't believe there was any temp fluctuation. Could the action of losing krausen into the jug create negative pressure in the carboy? No water sucked into the carboy (to my knowledge) until I attempted to remove it. Was there water in the blow off hose already and I didn't notice it, and once I removed it from the water bucket it poured in? This seems to make more sense than anything. I've looked around the forums and am still confused on what went wrong. Northern Brewer suggested elevating the sanitized solution jug (which I did), and I've also read elevating it is not a good idea. From now on I am going to take blow off hose and replace with bubble lock after the first few days of fermentation. What went wrong? How do I prevent this from happening again? Should I not raise the blow off jug?
Here is my Set-up:
Here is my Set-up: