FWIW, the S-airlock typically has a fill line about halfway up the sides of the large cylinders. When I used S-airlocks in the past I would fill to those lines. I suspect that for the S-airlock just making sure there is liquid in it is sufficient for primary fermentation. The liquid permit the CO2 to escape and 'blocks' air from getting in. The three piece airlock is a 'better' airlock for long term storage of beer; there is less oxygen permeation through the three piece airlock. Cheers!
Jack, do you have convincing evidence or reasoning for this? For some reason, I had thought the opposite to be true, but I realize it probably came to me as heresay on a beer forum.
“…do you have convincing evidence…” Peter, that is entirely your judgement call. I have test data but if you choose to be not believe the testing source well… “…or reasoning for this?” A link to a technical paper is below. An S-shaped airlock has an average daily O2 transfer rate of 2.6 cc/day. A three piece airlock has an average daily O2 transfer rate of 1.6 cc/day. http://www.mocon.com/pdf/optech/Closures - Oxygen Passage Study.pdf Cheers! Jack
I had picked up somewhere that the S type airlocks were better for long term aging as well, but do prefer the 3 piece airlocks. Guess I can better justify that practice now.
3 piece airlocks are easier to clean. That is my only reason for preferring them until now. thanks @JackHorzempa
The reason I wanted to buy some S Style is because I am going to start cold crashing, and I don't want the beer drinking all of my star san.
No microbes can get in and around the U shaped bend. Especially if there's Star San in there. To Cold crash, I just sanitize a piece of aluminum foil and put a brick over the grommet.
Airlock challenge: split a batch and use different airlocks. Compare the beers blindly. Discover it doesn't matter which airlock you use.
Thanks, Jack. I have no reason to disbelieve the data shown in the paper, although in truth, I just skimmed it and looked at the charts. Maybe a more thorough read would make me question something, but probably not. Didn't mean to come across as skeptical of you or your assertion. Just wanted to learn where it came from. When I first started using airlocks, I went with the 3-piece for cleaning ease. But somewhere along the way, I was steered to the S-type for prolonged secondaries. I do not recall the source of that info (it's either a podcast or a forum) but perhaps it was flat out incorrect or I misinterpreted what I heard.
