Why aerate wine?

[oats]

Im a newbie to making wine but im used to the science behind it and I have read that a lot of these recipes, you leave the primary fermentation open and exposed to air then after a certain amount of days they airlock it.

I was under the impression that when you introduce air into the mix, yeast will produce vinegar. Whats the point of leaving it open to air?

 

[Yooper]

Im a newbie to making wine but im used to the science behind it and I have read that a lot of these recipes, you leave the primary fermentation open and exposed to air then after a certain amount of days they airlock it.

I was under the impression that when you introduce air into the mix, yeast will produce vinegar. Whats the point of leaving it open to air?

Yeast never produce vinegar. Acetero bacter, a strain of bacteria often carried by fruitflies, is the strain of bacteria that produces vinegar. In short, aceterobacter "eats" alcohol and produces vinegar. It can't happen unless there is alcohol present, as well as the bacteria.

Oxygen is very good for yeast reproduction and it's good to stir the wine must to knock down the cap as well as to degas it during fermentation a bit. Co2 pressure causes fermentation to stall.

 

[oats]

Oh ok cool thanks! I shall definitely do that. And I guess how does Acetobacter get into some batches? Does it float around in the air?

 

[Dicky]

After a little research I concluded the follow.

You're mainly going to find it on outside elements that contaminate the wine, as suggested via fruitflies. That's not to say that it can't just find it's way in there.
But I'm as reliable as Wikipedia.

To be honest, when I've made wine I've air locked it pretty quickly. Leaving the yeast open to get going for a day or so is a good idea, but make sure you seal your container with a breathable lid such as muslin to stop anything from getting in.