Not Everything Should Be Fermented

Fermentation depends on the right food, the right microbes, and a process that keeps things safe.

• Fermentation
• Food Safety
• Food Preservation

It feels almost like you can ferment just about anything. You can ferment flour and make bread. You can ferment sugars and get alcohol. You can ferment fruit juice and get ciders and wines. You can ferment vegetables in a brine and get pickles. You can even ferment milk and get yogurt and cheese.

However, there’s a very important thing all of these have in common: sugar.

Sugar is nature’s food. It’s the favorite of all kinds of microbes. Some are symbiotic with more complex animal life, while some can be extremely dangerous.

When fermentation was discovered and became an intentional practice, it was a method of preservation by introducing good microbes to eat all the compounds that bad microbes would find appealing (like sugars). As we’ve learned more about how fermentation and food preservation works, we’ve also discovered that in some cases fermentation can starve these bad microbes of things like oxygen so that they can’t reproduce or consume the non-fermentable compounds and create potentially harmful byproducts.

So while this means that there is certainly a lot that you can ferment, especially if you carefully watch the environment and make sure that only the good microbes take hold, it’s best to stick to the common safe fermented foods and stay away from trying anything risky.

For instance, if you try to ferment something that simply doesn’t have enough sugar, the good bacteria and yeast won’t wake up, won’t reproduce, won’t ferment anything, and will leave plenty of food (cellulose, fat, etc.) for other bad microbes (e.g. molds). This will result in something unpalatable at best (ever forget about a salad in your fridge?) and poisonous at worst.

If you try to ferment something that has already been preserved (especially chemically preserved) it may lack enough naturally-occurring bacteria and yeast to start a fermentation or kill any bacteria and yeast that you introduce to it.

Additionally, there are different ways to ferment, but they are not interchangeable. Different cultures, different amounts of salt, and different amounts of oxygen can be factors that would lead to a successful fermentation on one food but a dangerous one on another.

All that being said, the safest option is to follow the right process to properly ferment only foods that have been safely fermented for thousands upon thousands of years. Which, thankfully, is still quite a lot.