Purpose of airlock

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joydivision

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I understand how it shows if the beer is fermenting but serve any other purpose ? The reason I ask is I couldn't find my middle piece when I finished brewing. I just placed the airlock and lid on. I trust it will ferment.
 

forstmeister

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The airlock allows CO2 to escape through a safe passage. Also does not allow oxygen into the fermentor.
 

progmac

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to prevent any contamination, you may want to bottle soon after the primary has died down
 

unionrdr

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I'd go looking for that missing centerpiece. That's the business end of the system. The part that acts as a valve to let co2 escape,but keep air out.
 

Effingbeer

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I usually let the first few days in primary go without an airlock. I just put on some starsan-soaked aluminum foil. Just after high krausen I add the airlock. All you have to do is keep anything from falling in. After the krausen drops, it's a different story. Less protection up top allows o2 diffusion. But you got a few days before you need to come up with a new airlock.
 

Demus

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As an indicator of fermentation, it's unreliable. It's real purpose is preventing contamination. Without the middle piece you have a path air can take into your fermentor. That air could contain mold, wild yeast, bacteria, insects and who knows what else. Fermentation will still take place, but some of it might be by organisms other than your desired yeast. This could cause serious flavor issues. Or, you could get lucky and get a great tasting beer. If this happens thank the beer gods, but don't for a minute let yourself believe you don't need a properly filled airlock to prevent invaders!!
 

Demus

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I usually let the first few days in primary go without an airlock. I just put on some starsan-soaked aluminum foil. Just after high krausen I add the airlock. All you have to do is keep anything from falling in. After the krausen drops, it's a different story. Less protection up top allows o2 diffusion. But you got a few days before you need to come up with a new airlock.
I'm not doubting this works, but I used to do my starters this way. Then one fine day I checked on a starter in a kitchen closet. To my horror I found a trail of ants climbing up the side of the flask, under the foil and down into the sweet treat below. Needless to say I chucked the culture of yeast ants rather than pitch it into brew. I invested in an 89 cent foam stopper and haven't had a problem since. Not every contaminant "falls" in; some "crawls" in!!!
 

duffbeer71

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I have found ants crawling over my carboy this spring. The airlock definitely saved the beer from being infested. I believe there are some natural foods toucan place in proximity to the beer that will keep them at bay like garlic or coffee grounds.
 

mikescooling

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Primary fermentation is aerobic, vs, secondary that is anaerobic (no O2). The airlock lets the O2 out and keeps a layer of co2, on top of the beer.
 

Effingbeer

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unionrdr said:
Yeah,those lil ants or them pesky fruit flies!
Thankfully, I've never had this problem. I have taken precautions and I realize that my process is not for everyone, but I wanted to give the OP a little peace of mind. I do believe he needs to airlock soon.
 

unionrdr

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Yeah,at least find the airlock center piece. I had a d'oh! moment myself today. Finally got the car towed to a performance repair kind of shop,& driver didn't look/ask for the keys,& I forgot. I have no car to go to the south end of the next town to drop'em off either. Damn!...:mad:
 
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joydivision

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Should I put some starsan in it? I can't get a new airlock until tomorrow. I finished brewing sat night.
 

mikescooling

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I'd stick it on dry, because without the middle it's going straight up anyway, you'll be fine.
 
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joydivision

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I bought a new airlock today poured some starsan in it and popped the middle piece on. It's been on dry for about 3 days. It's not bubbling should I be worried?
 

woozy

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I bought a new airlock today poured some starsan in it and popped the middle piece on. It's been on dry for about 3 days. It's not bubbling should I be worried?
No. The airlock doesn't affect fermentation. Fermentation affects the airlock.

After three days your fermentation should be winding down.

===== added ====

To answer your first question, the purpose of an airlock is solely sanitary. It lets air out without letting air in. Its use as an indicator of fermentation is coincidental and fortuitous. The risk you have in not having one was that your beer had some, albeit it very minor, exposure to air and so you have a slight risk of contamination. This in no way would affect your fermentation.

In other words, had you had a properly installed and working airlock from the very beginning, your beer and its bubbling would be *exactly* the same as it is now.
 
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joydivision

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How can air get in when I have the top on the airlock? II don't see how the middle piece keeps the air from getting in. I understand how the airlock can be used for letting the co2 out without letting air in but I never got the need for the middle piece and liquid.
 

stvo

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If you look really close the top has holes in it. Air coming in gets blocked by the liquid and the portion of the cap that's not submerged.
 

BryceL

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When the middle piece is on, the bottom of it should be below the water line, thus preventing air from coming up under it and in. The co2 will push the middle piece up and bubble up through the water and out. It essentially creates a one way seal
 

woozy

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The middle piece sits on the top of the valve like a lid on a boiling pot. The co2 from inside can pop the lid open and the c02 can get out but the air outside can't get through the lid. It's not an airtight seal but it's a good enough seal. But the one-way pressure of the co2 escaping and the only entry being through a pool of sanitizer make it decent.
 

boscobeans

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I have found ants crawling over my carboy this spring. The airlock definitely saved the beer from being infested. I believe there are some natural foods toucan place in proximity to the beer that will keep them at bay like garlic or coffee grounds.
If you have crawly things and want to keep them out of a fermenter put the entire thing in a tub of water with detergent in it or sprinkle some food grade diatomaceous earth around the fermenter in a six inch band.

OMO

bosco
 
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joydivision

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So if the krausen has not fallen I'm probably ok? How soon does the krausen fall? I went three days w a dry airlock.
 

Effingbeer

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joydivision said:
So if the krausen has not fallen I'm probably ok? How soon does the krausen fall? I went three days w a dry airlock.
Yes. I usually go 3-5 days without an airlock, depending on the yeast activity.
 
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