FAQ: Fermentation
What is Fermentation?
Fermentation is a preservation method that occurs through a natural chemical process. It involves breaking down glucose molecules in food without the need for oxygen. In simpler terms, fermentation happens when yeasts from the air attach to a food product and consume its sugars. The byproducts of this process are carbon dioxide and either ethyl alcohol or lactic acid. As the food undergoes this transformation, it becomes either more acidic or develops alcohol content. Common examples of fermented foods include wine, beer, kimchi, pickles, miso, sourdough bread, vinegar, and sauerkraut.
How do I preserve food with fermentation?
Fermentation is a simple yet effective method for controlling microbial growth. To get started, you’ll need a scale, salt, fresh food (vegetables or fruit), a vacuum sealer, and either vacuum-seal bags or a sanitized crock with a weight and lid. Here’s how to proceed:
Prepare the Vessel: Tare (zero out) your crock or vacuum-seal bag.
Add Ingredients: Place all the ingredients you want to ferment into the crock or bag, including water if necessary and any seasonings.
Calculate Salt: Weigh the contents of your vessel in grams. Multiply this weight by the percentage of salt you want to use (1.5%, 2%, 2.5%, or 3%). The result is the amount of salt (in grams) you need to add to the vessel. Mix the salt thoroughly with the ingredients.
Seal and Submerge: Vacuum-seal the bag or press the weight into the crock to ensure the ingredients are submerged.
Date and Store: Label the vessel with the date and store it in a cool, dark place. Allow it to ferment for 14 to 90 days, depending on the recipe and desired flavor.
As the fermentation progresses, you’ll notice the vacuum bags expanding due to the production of carbon dioxide. It is okay to move the bag during the fermentation process.
Why is salt necessary for fermentation?
Salt plays a crucial role in the fermentation process. It draws moisture out of the fruits and vegetables, which helps create an environment that inhibits the growth of undesirable bacteria. As the salt pulls out water and natural sugars from the food, good bacteria start to grow. These bacteria produce lactic acid, which not only contributes to the preservation of the food but also facilitates the fermentation process, transforming the ingredients into a fermented product.
What type of salt should I use?
For fermenting we recommend utilizing sea salt, this is because it is naturally packed with nutrients. Our second choice is Kosher salt due to the size of the grain. We avoid iodized salt for many reasons, one reason being the grain is too small. Secondly, it often contains anti-caking agents which we like to avoid and it has a very different salinity than sea salt. For more information on SALT, click here to read our blog.
How much salt should I use?
For effective microbial control during fermentation, a salinity of 2% is generally recommended. However, the ideal salt concentration can vary depending on the type of ingredient you're fermenting:
Meats: Use 2-3% salt relative to the total weight of the product. This higher concentration helps manage microbial growth effectively.
Vegetables and Fruits: Opt for a lower salt concentration of 1.5%. This amount is usually sufficient for proper fermentation without overwhelming the natural flavors.
Adjusting the salt concentration based on the type of ingredient ensures optimal fermentation results.
How long do I leave the product to ferment for?
The fermentation time for your product depends on both the density of the ingredient and its natural sugar content. Additionally, the ambient room temperature plays a significant role: warmer temperatures (70-80°F) accelerate bacterial growth and fermentation, while cooler temperatures (30-40°F) slow it down.
Here are some general fermentation times based on different ingredients:
Plums: 2 weeks (soft flesh, high sugar)
Apples: 4-6 weeks (medium flesh, high sugar)
Green Tomatoes: 4-6 weeks (medium flesh, medium/low sugar)
Corn: 4-6 weeks (hard flesh, medium sugar)
Cabbage: 8-12 weeks (hard flesh, low sugar)
Adjusting fermentation time according to these factors helps achieve the desired flavor and texture.
Resources:
Britannica: https://www.britannica.com/science/fermentation
National Library of Medicine: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723656/