# Primary fermentation: Airlock or no airlock?



## Slyder73

Hi all.
Have enjoyed the information everyone is sharing with everyone on this forum. For a beginner I"ve learned a lot very quickly.

I have my 2nd and 3rd batches a few days into primary fermentation. However, in reading here and on several other wine sites as well as youtube videos I am a bit confused about something.

When starting a kit wine, the primary fermentation, should there be an airlock or should it be open to the oxygen (covered with a cloth)? Many sites suggest no airlock as the yeast need oxygen in the first few days. Many sites and many here airlock as well. I've had my first batch turn out great and my two current batches, one in a glass carboy are bubbling up a storm and the yeast in no way seems compromised.

Is there a concensus on airlock for primary fermentation? Personal preference? Is it different for yeast cultured for wine kits? Has anyone found a difference between both methods?

Thanks.


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## AlFulchino

what sites are showing an air lock on a primary???

the primary ferment needs O2...the wider the top surface area the better


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## Wade E

Almost all kit manufacturers state to use a airlock. I myself use an aorlock but aerate my must at least once every day. I have a cat that lives in my basement and can get into things so Ive always used the airlock and have never ha a problem yet with any problems over many years. If you have good conditions then by all means leave it to get more 02 but just make sure no bugs can get in there.


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## AlFulchino

wow Wade...i dont do the kits like you do....but i have never used an airlock in primary...i suppose a cat would be an issue, especially if they stood by the primary and a fly was cavorting above the primary


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## Wade E

Actually my cat loves to sit on everything so if the lid was on loose he would probably flip it over and go for a swim or just spaz and leave my wine open to anything.


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## Tom

I'm also like Al. I rarely add an airlock to the primary. Now I dont do that many kits BUTT, I do a $___ load of fresh juice and fruit. I also rack before its dry like around 1.015.


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## St Allie

For kits.. I add an airlock.

For homemade recipes I stir daily for the recipe requirements. Add airlock usually after 4 days minimum ( 6 maximum)

never had an issue with either requirements.

Allie

XX


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## Slyder73

Thanks for the replies all.

What I'm curious about is the mechanics of it all. Given that the CO2 produced is heavier, and in essence creating a CO2 blanket on the surface of the wine, if there is no airlock, how does O2 (being lighter), get down through that layer of CO2 and into the wine solution? Especially when the CO2 is constantly "pushing" upwards against the lighter O2. This would be even more pronounced if fermenting primary in a carboy, I can't see how it's even possible for Oxygen to travel down against the heavier Carbon Dioxide and into the narrow neck and enter the solution where the yeast can make use of it.

What seems to be making sense from the comments here and the reading I"m doing is there is a difference between Kit wine and fresh grape/fruit wines. The kits by my reading are designed to have the essential nutrients for the yeast without needing initial reproduction level oxygen? THe fresh ingredients need the oxygenation to help the yeast reproduce in the first few days?

As of now, with my kits I have the airlocks on, one in carboy, one in bucket and this discussion is more for interest sake at this point, but I can see in the future already wanting to move on to fresh ingredients and I think this might be an important point. 

Then again, perhaps I'm reading too much into it....never in all the research I've done heard of anyone having a destroyed wine by either method...so maybe both are good?


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## St Allie

Temperature, nutrients, acidity,and oxygen all play a part in the fermentation.

I don't know which sites or kits recommend an airlock on a primary fruit fermentation ( compared to a kit)

Oxygen is a big need for the yeast initially, starve the must and the ferment ceases. once the yeast is up and running.. as long as it has nutrient and sugars.. it keeps going.

I have given up on kits.. I was keen on them however,my homemade fruit wines are more complex and interesting a year down the track.

have planted my own vines now.. so unlikely to keep attempting kits.

you'll all have to cope with me posting


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## MBRA

Cant say for kit wines, never done one and probaly never will. The oxygen that desovles in your must when crushing the grapes is most of the times enough for the yeast. Only add O2 if ferm starts to lag. Also dep1ends on the style of wine making, like chardonnay(oxidative) can turn out awesome with a bit of O2, but forget about a citrusy one then. Sauv. Blanc you keap it as far away as possible and make the wine as reductive as you can.

And the previos Qeustion on how does O2 get past the CO2 layer, google Bhor's Gas law, that plus a light breeze.


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## Zoogie

I always use an airlock ...and have yet to have a problem.. all the wines I have done kits and non kits came out great...well... except for the grapefruit
will leave its sit and age but to me its nasty tasteing lol bth way looks like you have great spot for growing your vines  Zoogie


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## STEEDTUCKER

i have never had a problem with kit wines or fresh fruit wines fermenting under an air lock. i know beer brewers use air locks as well. the beer has been boiled for 60 min plus....this is before it is fermented. boiling for that long would boil out a lot of oxygen and all beer brewers ferment their beer under an air lock with no problem. i would think that a must which has not been boiled would have much more oxygen within it than some wort that a brewer just boiled. i think sometimes people may look into things a little too much. i feel that it probably is just personal preference....all this is coming from someone that only makes 6 gallon batches....the oxygen may play a different role if the batches are larger but im not sure.....anyway everything i have ever fermented...beer/wine has always been under an airlock and i have never had a stuck fermentation.


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## wyntheef

I airlock my wines (both kit and juices) in a bucket type primary. Mostly for the reasons Wade stated. Not wanting flies or other interested creatures having access. 
So far, I haven't had any trouble at all with fermenting, but from now on I'm going to start stirring the must for the first few days. For some reason I thought it was a no-no to be stirring it up. Still, as I said, no problems that I'm aware of to this point.


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## ffemt128

I've only made a couple items so far but both kits as well as my apple and tropical breeze I have airlocked the primary. The scratch wines I set the lid with airlock in place so that I could stir daily and squeeze the straining bag.


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## cpfan

This is one of those wonderful questions that comes up on the forums on a regular basis. The only real answer (as shown above) is "It's YOUR Choice".

Personally I do not use an air-lock on my primaries. This is partially because of the style of primary that I use. But many folks do use an air-lock. I know of people who have created a hole for an air-lock in the lid of the primary that I use.

It is my understanding that a good vigourous stirring before pitching the yeast should incorporate enough oxygen into the must for the yeast to survive, so that isn't really an issue.

So basically, it's your choice.

Steve


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## barslater

can I ask a question about the direction of the gases in the airlock chambers?

my single piece s-airlock goes one way showing that the wine is still off gassing, i.e. fermenting and producing co2. at times it is sucking in, is it seeking gas for some purpose? it is almost time to bottle the 2 year old wine so it is a moot point, but I would like to know more about the other side of air lock behavior. thanks


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## bkisel

barslater said:


> can I ask a question about the direction of the gases in the airlock chambers?
> 
> my single piece s-airlock goes one way showing that the wine is still off gassing, i.e. fermenting and producing co2. at times it is sucking in, is it seeking gas for some purpose? it is almost time to bottle the 2 year old wine so it is a moot point, but I would like to know more about the other side of air lock behavior. thanks



Welcome to the forum!

My best guess is your seeing, after the must has pretty much pumped out most of the CO2, is the result of changing atmospheric pressure. Again, just a guess.


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## richmke

Two major factors that would draw air into the carboy are: 1) change in air pressure; and 2) change in temperature.

The more gas you have in the carboy (head space) the greater the effect of change in air pressure. When the weather is nice, it is usually associated with High Pressure systems, and that would push air into the carboy.

Change in temperature causes thermal expansion/contraction of the wine. As temperature drops, the volume of the wine decreases, and draws in air.


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## Tom_S

There's been quite a bit of debate on whether or not an airlock on primary fermentation is a good thing to do or not, and I've found personally that it really doesn't make any difference at all. I've done it both ways and have never had a problem either way.

From everything I've read about yeast and fermentation, the yeast goes through two stages after you pitch it into your must. The first stage is reproduction, and this is the stage where oxygen is important. The yeast need oxygen to reproduce enough to have a big enough colony in the wine in order to effect fermentation. Once they've reached maximum density, so to speak, they stop reproducing so much and focus on changing sugar to alcohol. In this stage, they don't need oxygen since they become anaerobic. 

So basically, you need oxygen in your must the first few days after pitching yeast, but once a vigorous fermentation takes off there's going to be a blanket of CO2 constantly pushing all other air out, so there's no way for oxygen to reach the yeast even if they needed it. So I say it doesn't matter if you put an airlock on at this time or not. I do and have never had any problems, but I always do it after there's a vigorous fermentation and the must is bubbling like freshly opened champagne.

*edit* Sorry I didn't realize this was a revived old thread. But the above is my opinion.


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