Why do vegetables need to be kept submerged under brine during fermentation, and how do I achieve that?

Question

Why must vegetables be kept submerged under brine? Understand why this is critical for preventing mold and learn easy ways to achieve it in your jar.

Answer 1

Vegetables need to be submerged in brine during fermentation to prevent mold growth and ensure anaerobic conditions for beneficial bacteria. This is achieved by using weights like glass jars, fermentation weights, or even a clean plastic bag filled with water.

Detailed Explanation:

During vegetable fermentation, we're encouraging the growth of beneficial bacteria, primarily lactic acid bacteria (LAB). These bacteria thrive in an anaerobic (oxygen-free) environment. When vegetables are exposed to air, undesirable microorganisms like mold and yeasts can grow, potentially spoiling the ferment and making it unsafe to eat.

Submerging the vegetables in brine serves several crucial purposes:

1. Creates an Anaerobic Environment: The brine acts as a barrier, preventing oxygen from reaching the vegetables and creating the ideal conditions for LAB to flourish.

2. Inhibits Mold Growth: Mold requires oxygen to grow. By keeping the vegetables submerged, you deprive mold of the oxygen it needs, preventing its growth.

3. Promotes Even Fermentation: Consistent submersion ensures that all parts of the vegetables are exposed to the brine and the beneficial bacteria, leading to a more uniform fermentation process.

To achieve proper submersion:

1. Pack Tightly: Pack the vegetables tightly into your fermentation vessel, leaving some headspace at the top.

2. Add Brine: Pour the brine over the vegetables, ensuring they are completely covered.

3. Use Weights: Place a weight on top of the vegetables to keep them submerged. Suitable weights include:

   • Glass Jars: A smaller glass jar filled with water or brine can be placed inside the larger fermentation jar.

   • Fermentation Weights: These are specifically designed weights made of glass or ceramic that fit inside fermentation jars.

   • Plastic Bag Filled with Water: A clean, food-grade plastic bag filled with water can be used as a weight. Ensure the bag is sealed tightly to prevent leaks.

   • Cabbage Leaf: A large cabbage leaf can be placed over the vegetables before adding the weight. This helps to keep smaller pieces from floating to the surface.

4. Monitor Regularly: Check the ferment regularly to ensure the vegetables remain submerged. If necessary, add more brine to maintain the liquid level.

Pro Tip:

Use a fermentation airlock on your jar. While submersion is key, an airlock allows gases produced during fermentation to escape without letting oxygen in, further reducing the risk of mold and yeast growth.