The airlock or fermentation lock is an essential tool of wine making. This device allows carbon dioxide (CO2) to escape as yeast converts sugars into alcohol and CO2, without allowing oxygen or contaminants to get into the wine.
Airlocks are cheap if you have a local supplier, but even cheaper to make with items found around the home. As I intend to keep several batches of wine fermenting at the same time, I’ve started making my own airlocks (also known as “bubblers”—the term I prefer) on the homestead.
I made my own airlocks with a medicine bottle, a pocket-size hand lotion bottle, such as one would get from a hotel, and a pen barrel. The last I ended up replacing with polyvinyl tubing, as I’ll explain below.
I don’t know the technical terms for the parts of an airlock, but looking at my photo above, you see it’s a cylinder with a central shaft or tube, a cap to cover the top of the tube, and a lid for the cylinder.
I drilled a 3/8″ hole in the bottom of the medicine bottle, right in the middle of the central dimple. I also drilled several tiny holes in the medicine bottle’s lid (to allow CO2 to escape).
The lotion bottle, which could be any similarly shaped bottle for shampoo or other liquids, provides caps for two bubblers. The lid of the bottle makes one ready-made; I cut off about an inch of the bottom of the bottle to make the second one. Anything that will catch gas as it escapes and fit within the bottle/cylinder will work just as well.
I cut the pen and removed its inner workings to leave a tapered shaft. I thought the taper would be adequate to go up through the hole in the bottom of the bottle and seal it, but that hasn’t worked very well. Temperature fluctuation makes the pen swell and shrink, and the water leaks out.
I solved this with 39¢ worth of polyvinyl tubing, enough to make four 3″ tubes. I got 7/16″ outer diameter, which jams into that 3/8″ hole tight enough to seal in the liquid.
If I run out of drilled rubber stoppers like the one at right, a 3/8″ hole in the lid of whatever bottle or jar I’m using as a fermenter fits the homemade bubbler, and I’m good to go.