Airlock on the primary?

[Luc]

I have to wonder, and we'll leave this one to LUC. if anyone has ever done a controlled experiment trying it both ways.

Thanks for the confidence Troy !!!

well as a matter of fact I am doing test batches (5 liter each) just to test what works better. And indeed there are differences........
I still have to examine all figures and details, and indeed I will have an article on this on my web-log in due time.

However in the mean time I can say this:
I always have an open fermentation in my primary. Meaning that I put a cheesecloth on my primary and do not use the lid with airlock.

First, I think it is easier to remove a cheesecloth (fastened with a rubber band) as removing the lid.
And I have to remove it two to three times a day for punching down the cap.

Next, remember I always make a yeast starter:
http://wijnmaker.blogspot.com/2007/08/gist-starter-yeast-starter.html

So my yeast will hit the must with full strength and fermentation will start within the hour.
Nevertheless I want my yeast colony to grow the first few days.
Growing is done by oxygen (aerobic fermentation).

Now there wil be a lot of oxygen in the must dissolved just by the way we make our must: dissolving sugar and acid by stirring etc.
But a lot of this will be expelled (in my opinion) soon as CO2 starts to form due to fermentation.
So stirring is a way to introduce fresh oxygen.

Now a fermentation will produce CO2 and that will form a layer on top of the fermenting must.
So above the must there will be not much oxygen around. This is what I presume. I have not measured that yet. Actually I just had an idea on how you can measure this, so I am going to try that soon.
The fact that there is not a lot of oxygen above the must is a good thing. Many bacteria (think acetobacter meaning vinegar) need oxygen.

However the laws of gasses dictate this:
as you walk by a fermenter with a cheesecloth on top you will form some turbulance. That might pull some CO2 out of the fermenter and pulls oxygen in.
However that will be dissipated (is that a good word, sorry for my english) soon enough by the CO2.

So in my humble opinion.
The only way you will get oxygen into a must is by stirring it.
Pushing down the cap gently is not enough. It will introduce some oxygen, however not enough to dissolve in the must.

And there is one more thing.
It is now understood that yeast create their own microclimate.
Meaning that contradictionary to what we used to believe is that yeast decide themselves when to start anaerobic (without oxygen) fermentation. Meaning that even with the lid off, the yeast decide themselves that they not need oxygen anymore. There is still research on that going on.......

However believe me: my test batches have indicated that there ARE differences in a wine made with an open fermentation (cheesecloth) and wines in a closed fermentation (airlock).

All my old winemaking books tell the following:
Put the must and pulp in a vessel and stir at least twice a day, punching the cap down.
When the cap collapses (meaning the cap sinks by itself to the bottom) it is time to press and bring the juice under an airlock.....
There are some exceptions like high tannin wines etc.

So no easy answer here.

I still ferment in an open vessel covered with a cheesecloth to keep the bugs out.
After a few days when vigorous fermentation stops I press, transfer to a carboy, or just place the lid on depending on the kind of wine I am making.

Luc

 

[270bob]

I have made only about 20 kits, so I'm fairly new to this compaired to some.
This is what I do, I ferment 5 days with a loose fitting top then I place a sealed top on fermenter with airlock. Usually fermentation to .994 or so takes 8 to 10 days. I also use brew belt. This works for me.

Bob

 

[Daisy317]

Okay lets take this one step further.

Cover with a cloth etc. Fine, but putting a lid on it seems to me to inhibit any oxegen entering to help the yeast "grow", and just cancels out the whole idea of the cheese cloth, save the cloth and do the lid anyway.

Guess I am really wondering is just how much oxegen is required to ensure a successful ferment?

So if we have no cats, no kids and no nosy friend or inlaws, WHY, even bother with the lid? Just leave the cloth on it.

Many people have had great successes with leaving a lid on the primary with an airlock. Many have never used an airlock at all during the primary.

I have to wonder, and we'll leave this one to LUC. if anyone has ever done a controlled experiment trying it both ways.

Are there differences in TEMP, so2, etc.

If the end result was to be the same, then I wonder why this would be a question at all.

Still curious. For me, cheesecloth.

Anyone?

Troy

With my luck... the time I don't put the lid on loosely I'll have a purple cat...

 

[Wade E]

Believe me Im not telling anyone that using the airlock is the better way, ive just had no problems doing it this way in many years. The bigger the batch is the more likely youll need to use open fermentation method as the gases will be concentrated meaning if you are making a 30 gallon batch in a 40 gallon container then youll really need to have an open fermentation unless you have a very wide opening vessel like a trough! Youll also be creating more heat in that vessel with all that fermentation and likely need a cooler area to ferment in hence why big wineries need liquid cooled fermentation vessels. Im just stating that from my experience these smaller batches (6 gallon in a 7.9 bucket) and stirring a few times a week have supplied the yeast with enough 02 to not have any problems at all like slow fermentation or any off flavors or smells or stuck fermentations. I do use both nutrient and energizer in all my wines so maybe thats also helping as to not have any problems. I will also state that once my currants are producing big volume Ill be getting a big primary vessel and be using the open method. Ill most likely take a lid and perforate the heck out of it with a drill and big drill bits and screen it from the inside.

 

[Dugger]

This is one of those questions that will be asked forever. I make only kits so that's where my experience lies. I use a solid lid (no airlock hole) sitting loose on the bucket and have not had a problem with fermentation. When RJS changed to a 2 week bucket ferment I drilled holes in some covers and now use a loose solid cover for the initial 5 days or so and then switch to a sealed airlocked cover for the remainder of the fermentation.
I believe that the initial mixing of the must generates enough oxygen for the aerobic yeast activity. I don't know how long this is but would guess it's one or two days. Then it goes anaerobic and oxygen becomes the enemy. I also believe a loose cover or cloth makes little difference in passive introduction of oxygen to the must through the CO2 layer.
Thus, a loose or sealed cover, in my opinion, really doesn't make much difference for fermentation. However, a loose cover ( or cloth) makes it a heck of a lot easier to punch down/stir and to take SG readings.
What I don't know or can even hazard a guess is whether the rate of fermentation makes a difference in the final product and whether periodic oxygen introduction affects this rate of fermentation ( certainly temperature does, but that's another question for another topic).
It will be interesting to see what Luc comes up with in his test results.
.. Doug

 

[Tom]

I have made only about 20 kits, so I'm fairly new to this compaired to some.
This is what I do, I ferment 5 days with a loose fitting top then I place a sealed top on fermenter with airlock. Usually fermentation to .994 or so takes 8 to 10 days. I also use brew belt. This works for me.

Bob

Sounds OK from here.