Air Lock on primary fermenter

I generally do not use a tight lid or airlock during primary fermentation. You should be fine with just a light cover, though i suspece if the must is well aerated to begin with, you will not have trouble with the yeast growth. Anyway, I would stir it every day during primary, which means you'd take the lid off.

I made a peach wine a two years ago that is really drinkable right now. I added golden raisins to give it some body as I have found other peach wines I've tasted lacked some body and was thin on the palate.

Here's my on-line log for the peach wine I made . . .

This I made another batch of peach wine which has recently finished fermenting and is clearing. Instead of raisins, I added some niagra white grape juice. I think this is also going to be good. I did bump up the amount of fruit this year. I'll have the details on my web page one of these days.

Please let us know how it turns out!

If you are punching down several times a day then it will get all the air it needs. But then if you are punching down several times a day, covering it tightly or using an airlock does noting but keep the bugs out. I generally just cover with heavy cloth.

Ray

Steve,

Initially, you need oxygen in order for the yeast to reproduce and build a sizeable colony. They don't need (additional) oxygen to convert sugar into alcohol (technically they obtain any oxygen they need from the must).

A loose-fitting cover, plastic sheeting, blanket, or tight-fitting cover with airlock are all suitable for covering a primary. The air in the head-space and in the must itself are more than sufficient for today's "fast-breeding" yeast. Especially, since you are going to be opening the cover and stirring the must (or punching down the cap) 2-3 times daily.

The purpose of the cover is to keep (and let) things out, not to let things in. It must be loose-fitting, or have an airlock, in order for the CO2 gases (produced by fermentation) to escape. You don't WANT to keep them in, or eventually something will break, crack, or explode.

However, when the fermentation first begins, there is an "explosion" (for want of a better term) of foam, and the airlock does not allow the gases to escape rapidly enough. So you end up with foamy must in your airlock and all over the table or floor. For this reason, a loose cover is preferable --- it will let more of that initial explosion escape quickly.

As long as the fermentation is still producing a significant amount of CO2 (as indicated by the number and size of bubble in the airlock, or the height and which the cap floats, and the speed at which it reforms after being punched down), the wine can remain in the primary. When the ferment slows down, you must move it to a secondary (which has less exposed surface area, and less air-space above the wine) with an airlock.