Recently I’ve heard from more than one confused beginning winemaker asking if their wine was ruined because they never put water in their airlock. It’s not all that surprising as a beginner has a lot to figure out with all the steps, additives, and equipment. I’m sure there are wine making shops that forget to mention that the airlock needs water. For a seasoned wine maker it’s just how things work.

An Academy member by the name of Robert recently wrote in with just this problem. He purchased everything he needed to make a kit wine but didn’t know that the airlock needed water in order to protect his wine. At the time he wrote in his wine had been fermenting for two weeks and was well past the vigorous fermentation stage.

So let’s take a look at which airlocks require water, which don’t, and how they work in the first place.

Which Airlocks Require Water?

Some airlocks require water and others don’t. The most common styles do require water and those are the “S” shaped and three piece airlocks as shown here.

These airlocks require water.

Here are two “S” shaped airlocks and one 3-Piece airlock. Both styles require water.

The water forms a barrier between you and your wine. Because of the shape of the airlock the carbon dioxide being released by the yeast is forced to go through the airlock, through the water, and then exit the airlock.

As the yeast produce carbon dioxide they cause pressure to build within the fermenter. When the pressure is great enough a bubble will go through the water barrier. This difference in pressure between the fermenter and the air outside the fermenter oxygen will not be able to flow through backwards through the airlock and interact with your wine.

Waterless Airlocks

A waterless airlock

This silicone stopper requires no water to protect your wine yet allows carbon dioxide to escape.

There are several varieties of airlocks available, such as silicone stoppers, that do not require any water yet still allow carbon dioxide to safely exit the fermenter. The most common waterless airlocks are made of silicon and have many holes that run from the bottom of the stopper to the top. On the top of the airlock is a silicon flap that is pressed open by the escaping carbon dioxide.

These waterless airlocks function much the same as the traditional styles. As the pressure builds in the fermenter the silicon compresses and the carbon dioxide goes out of the tiny openings in the stopper. Because there is already a gas leaving the airlock oxygen cannot get in. When fermentation slows down and is not releasing as much carbon dioxide the tiny holes will close up and keep oxygen from getting in.

These are great because you don’t have to worry about the water being blown out the top or drying up over time. Water filled airlocks can flow backwards and dump the water in your wine if fermentation has ended and there is a temperature drop in the wine.

What Can Robert Do Now?

Here’s my advice to Robert. Regardless of how long your wine has been unprotected it’s best to get it under a properly filled airlock as soon as possible. Once your wine is protected we can discuss what to do next.

Next, visually inpsect the wine. Are there any strange looking blobs of material floating in your wine? Spoilage organisms often cause black, brown, or white blobs to form that can get quite large. If you see anything like that chances are your wine has spoiled.

If your wine looks okay then move on to smelling your wine. As you might expect a wine that is in the process of becoming spoiled will give off some funky aromas. You might smell sulfur, burnt rubber or matches, barnyard like smells, or even decaying fruit. Each of these indicates that spoilage has occured or is currently happening.

Lastly, if your wine looks okay and smells okay you should taste the wine. Take a small sip to start with and pay special attention to both the flavor and the amount of bubbles you feel forming in your mouth. A still wine that all of the sudden is bubbly can indicate a spoilage organism is chomping away at something in your wine and giving off carbon dioxide.

As with smelling a wine if you taste burnt rubber, burnt matches, barnyard mustiness, or decaying fruit that is a bad sign. On the other hand, if your wine looks good, smells good, and tastes okay chances are your wine is in good shape. However, you will want to keep a close eye on things to make sure it doesn’t start to develop off flavors or aromas.

After you’ve determined that your wine is okay or at least drinkable it would be a good idea to add sulfites (if you use them) in order to protect your wine against spoilage organisms that may have found their way in but also against the oxygen it was exposed to. It won’t undo oxidation that’s already occured but it will help prevent further oxidation.

Proceed through the rest of the wine making process inspecting, smelling, and tasting your wine at each step to look for problems. The earlier possible issues are detected the easier they can be to remedy. Don’t wait until you open up your bottled wine to taste it just to find that it spoiled long ago.

But Matt, you don’t have to use an airlock…

More experienced winemakers will often forgo the airlock and ferment their wines in the open for the initial stages of fermentation. In fact most commercial winemakers will make red wines this way. The juice, skins, and seeds are left in large open containers and they ferment in the open for upwards of two weeks or so. The key to open fermentations is knowing when to get your wine under the protection of an airlock so you don’t risk oxidation or spoilage.

However, for the beginners out there I recommend using an airlock at all times until you have the hang of the fermentation process. You need to get a feel for when the more vigorous primary fermentation slows down and shifts into secondary fermentation (and by secondary I’m not referring to malolactic fermentation but the final stages of alcoholic fermentation).