# Primary fermentation with or without airlock?



## Brendan O'Donohue (Feb 11, 2018)

Hi,
I'll keep this question short!
Im doing primary fermentation in a plastic fermenter with a spigot and an airlock through a rubber grommit, should I try the next one with the lid not fully snapped on or maybe with just a towel over the top?
How will it get the oxygen it needs fully sealed with an airlock in place?
Cheers


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## sour_grapes (Feb 11, 2018)

Well, sure, it is fine to either place the lid loosely or cover with a towel.

As far as your second question, yeast are able to metabolize either aerobically (in the presence of oxygen) or anaerobically (in the absence of oxygen). ̶ ̶I̶t̶ ̶i̶s̶ ̶o̶n̶l̶y̶ ̶i̶n̶ ̶t̶h̶e̶ ̶a̶b̶s̶e̶n̶c̶e̶ ̶o̶f̶ ̶o̶x̶y̶g̶e̶n̶ ̶t̶h̶a̶t̶ ̶t̶h̶e̶y̶ ̶p̶r̶o̶d̶u̶c̶e̶ ̶a̶n̶y̶ ̶a̶l̶c̶o̶h̶o̶l̶.̶ ** Judging by the feeling I have right now, after consuming a few glasses of wine, I think they have mastered the art of dealing with low oxygen environments!

**I stand corrected on this point. See post #4 below by @balatonwine.


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## meadmaker1 (Feb 11, 2018)

Oxygen no oxygen. This was answered for me after about three days in a row pulling off that Xyz lid to punch down the cap. I now usually punch twice a day till I notice a drop in fizz and I believe my product is better for it. Far less likely to skip a punch with a loose lid


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## balatonwine (Feb 12, 2018)

sour_grapes said:


> It is only in the absence of oxygen that they produce any alcohol.



This is incorrect. There is even a name for it: The Crabtree Effect.


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## balatonwine (Feb 12, 2018)

Brendan O'Donohue said:


> should I try the next one with the lid not fully snapped on or maybe with just a towel over the top?



The towel over the top during part of the primary is just fine.

Even if the below article is for beer, I suggest it as something to read so you better understand how oxygen affects fermentation, and when during the process it is just fine to allow oxygen to the must (if not in fact encourage a moderate amount for other biochemical reasons):

https://www.morebeer.com/articles/how_yeast_use_oxygen


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## NCWC (Feb 12, 2018)

I like doing cold and closed top fermentation for whites or rose` and open for reds


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## Scooter68 (Feb 12, 2018)

One assumption falsely made, albeit an innocent assumption, is that a plastic lid actually seals out air. As many can certainly attest, even with a lid snapped tightly down, rubber grommet in place an an airlock. One may see little to no activity in the airlock because lids even with their soft sealing ring inserts don't actually seal well. I had this happen several times with different fermentations. I was using a low foaming yeast in a room with temps in the mid to upper 60's. While my hydrometer reading told me fermentation was going on, there was no activity in the airlock. On a whim I wet down the seal in the lide and reclosed the container. Viola! activity in the airlock - for a few hours until the moisture helping the seal went away. 

What that means in simple terms is that a tightly snapped on airlock is not a guarantee that you have sealed out much of anything. Might as well save yourself the trouble of snapping om and taking off that plastic lid. As meadmaker1 says, the pain of taking off and putting on that lid acts more as a discouragement for doing a proper punch down than it does as a seal to keep out air. So loose lid with a towel, or towel only. 

The only thing I would add different is that I just us a towel but I tie a cord around to help keep out fruit flies and other critters. We all know that fruit flies can't hold their liquor so once drunk on your new wine must they can't find their way back out, then they die and contaminate a wine must. So I use a towel to help them fruit flies practice abstinence.


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## JohnT (Feb 12, 2018)

IMHO, a lid is not required. The expelling CO2 from produced by fermentation will keep out the O2. Also, a little O2 in the beginning of fermentation is beneficial.


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## meadmaker1 (Feb 12, 2018)

I typically pull a 5gallon paint strainer over the bucket and lid.
The theory is that the flies will focus on entering around the edge of to lid but the only way in is 12" lower, and comes with elastic band.
Has worked better for me than a towel.


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## Brendan O'Donohue (Feb 12, 2018)

Ok, thanks.. so I'll just stick a towel or paint strainer over next time. 
How long is oxygen beneficial from the start of the primary fermentation... couple of days after it starts?
I'm about to start a more expensive kit next and don't want to screw it up!
I got the Atmosphere Amarone 16L kit which is a step up from the Beaverdales I've been doing.. or so i read anyway!


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## GaDawg (Feb 12, 2018)

I use a towel and a bungee cord around my fermentation bucket.


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## balatonwine (Feb 13, 2018)

Brendan O'Donohue said:


> How long is oxygen beneficial from the start of the primary fermentation... couple of days after it starts?



Ah. Well. That is part of the art of wine making. Everyone probably has a different opinion there as each answer is simply a different wine making style.

But, as a general rule, I (thus only my opinion of course  ) never go without air locks once the yeast has used up 2/3 of the sugar in the must. Around that time must sugar and CO2 blow off is reduced to the point that O2 contact becomes a real problem. I may even put on airlocks earlier. Depends on what type of wine I want to make.

But again, that is just me.


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## tjgaul (Feb 13, 2018)

NCWC said:


> I like doing cold and closed top fermentation for whites or rose` and open for reds


I'll go with NCWC . . . I might start a white with an open top for a day or two, but then go to airlock. I generally ferment my whites slow and cold using K1-V1116. So far they have all progressed fine mostly under airlock and even at temps below 60. 

Reds get the open top treatment until the SG approaches 1.010 and then they go on airlock too. I too have experienced the seeping gas around the cap syndrome. Always trust the hydrometer. I got a supply of very basic thin white dishcloths which when doubled up and attached with a bungee cord give adequate protection from the pesky insects, but allow good airflow. 

Just one more opinion.


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