It is absolutely possible to ferment food without an airlock. While an airlock can be a convenient tool for fermenting, it is not a necessity. In fact, our ancestors have been fermenting food for centuries without the use of modern airlock systems.
When fermenting food, the key is to create an environment that promotes the growth of beneficial bacteria while inhibiting the growth of harmful bacteria and mold. This can be achieved by using a brine solution, which creates an inhospitable environment for harmful microorganisms.
To ferment food without an airlock, there are a few methods you can employ to ensure a successful fermentation process. One common method is to use weights or stones to keep the food submerged under the brine. This helps prevent the growth of mold or yeast on the surface of the food.
Another option is to use glass or ceramic fermentation weights specifically designed for this purpose. These weights can be placed directly on top of the food to keep it submerged. The weight of the fermentation vessel itself can also help keep the food under the brine.
If you don't have access to weights or fermentation weights, you can also use a plastic bag filled with leftover brine as a makeshift weight. Simply place the bag on top of the food to create a barrier between the food and the air, keeping it submerged.
It's important to note that during the fermentation process, carbon dioxide is released. Without an airlock, this gas may build up and create pressure inside the fermentation vessel. To prevent any potential issues, it's necessary to “burp” the container by opening it slightly to release the built-up gas. This can be done once or twice a day, depending on the activity of the fermentation.
I have personally fermented various foods without the use of an airlock and have had successful results. For example, I have fermented sauerkraut using glass weights to keep the cabbage submerged in brine. The fermentation process proceeded smoothly, and the resulting sauerkraut was delicious and tangy.
While an airlock can be a useful tool for fermenting food, it is not essential. As long as the food is submerged under a brine solution and the fermentation vessel is “burped” regularly to release excess gas, you can successfully ferment food without an airlock.