Kimchi Mould Mastery: 6 Powerful Tips to Keep Your Ferment Fresh

Have you ever opened up a jar of homemade kimchi only to find fuzzy white or black mould covering your carefully fermented veggies? It’s a gut-wrenching moment for any kimchi lover. But before you toss the whole batch, stop! Some kimchi mould may be salvageable if you catch it early. This guide will walk you through how to ferment kimchi properly to avoid mould, how to identify harmful mould growth, and what to do if you discover your kimchi has mould. Let’s dive in and demystify kimchi and mould!

How Kimchi Ferments Without Mould

To understand how kimchi gets mouldy, first we need to understand how it ferments properly without mould.

Kimchi is a traditional Korean dish of salted and fermented vegetables like napa cabbage, radish, scallions, and carrots. The fermentation process is what gives kimchi its unique sour taste and dense probiotics.

During fermentation, beneficial lactic acid bacteria like Lactobacillus feed on the sugars in the vegetables. As they digest the sugars, the bacteria produce lactic and acetic acid as waste products. These acids cause the pH of the kimchi to drop quickly, creating an acidic environment.

Most moulds and harmful bacteria cannot survive at such low pH levels. This makes kimchi inhospitable to mould growth during proper fermentation.

3 Keys to Mould-Free Fermentation

There are three key factors that encourage healthy fermentation without mould:

Salting – Salt draws water out of the vegetables, creating brine. The 2-3% salt brine concentration prevents growth of bad bacteria but allows good bacteria to thrive.
Submerging – Keeping vegetables fully submerged under the brine eliminates oxygen. Aerobic moulds need oxygen to grow.
Air removal – Packing kimchi tightly into the jar forces air pockets out. Limiting air exposure prevents mould growth.

Follow these guidelines, and your kimchi has a solid defence against mould during the fermenting process. But accidents still happen, which leads to the dreaded kimchi mould.

Can Kimchi Grow Mould?

Unfortunately, the answer is yes. Given the wrong conditions, various moulds can gain a foothold and spread throughout your precious jar of kimchi:

Causes of Kimchi Mould

Insufficient salt – Too little salt leads to improper fermentation. The pH stays too high to stop mould.
Oxygen exposure – Any air pockets or surface exposure to air allows aerobic mould to grow.
Temperature changes – Fluctuating temperatures disrupt fermentation.
Contaminated equipment – Unclean utensils, jars, or hands introduce mould spores.
Over-ripening – Letting kimchi ferment too long gives mould a chance to develop.

Within a day or two of exposure to air, you may notice the first signs of mould on your kimchi:

Fuzziness – Mould starts as tiny hairy spots on the surface of veggies or brine.
Color changes – Blue, green, black hairy dots signal mould.
White film – Powdery white coating could indicate kahm yeast or mould. Kahm yeast is not a health concern (although it may make the taste less appealing). However, if you’re new to fermenting it may prove alarming.
Putrid smell – Foul, rotten odours mean spoilage.

Once mould takes hold, it can rapidly spread throughout the kimchi, ruining the batch. Time to toss it out, right? Not so fast! With quick action, you may be able to rescue some or all of the kimchi.

Tips to Keep Kimchi from Growing Mould

Preventing kimchi mould starts with mastering the fermentation process. Here are pro tips to keep your kimchi mould-free:

1. Use the Right Salt Ratio

Measure out your salt carefully and aim for a 2-3% brine concentration. Weigh the salted veggies, then multiply by 0.02 or 0.03 to determine the grams of salt needed. Too little salt and kimchi mould will run rampant.

2. Submerge Vegetables

Once salted, pack vegetables firmly into a jar and pour over brine to cover completely. Leave at least 1 inch of headspace and use a tamper to remove air bubbles. The veggies must stay fully submerged during fermenting.

properly submerged veg helps prevent kimchi mould

3. Limit Air Exposure

Tightly pack the kimchi into the jar, pressing out air pockets. Leave just enough room at the top for the brine to rise. Any trapped air or headspace allows mould to grow.

4. Maintain Proper Temperature

The ideal kimchi fermentation temperature is 15°C to 20°F. Avoid large temperature swings. Warmer temperatures above 24°F speed fermentation but increase mould risk.

5. Use Fermentation Lids

Invest in special fermenting lids with airlocks. These allow carbon dioxide to escape while keeping air out. Regular lids must be “burped” daily to prevent pressure buildup.

6. Monitor and Remove Mould Promptly

Check your kimchi daily when fermenting. At the first sign of mould, remove immediately before it spreads.

Follow these guidelines religiously, and you’ll almost never see mould devouring your kimchi creation. But what if some fuzz does sneak in? How do you know if it’s harmful and requires discarding the batch?

Identifying Harmful Kimchi Mould

Seeing mould on your kimchi isn’t always a death sentence. Some types of mould are harmless, while others spell doom for your precious fermented food. Here’s how to diagnose what type of mould has invaded your kimchi:

Appearance

Fuzziness – Mould has a hairy, speckled appearance.
Dryness – Mould sucks moisture out, leaving vegetables dry.
Spots – Dotted clusters of mould spread across surface.
Colour – Black, blue-green, orange, pink signal hazardous moulds.

Texture

Sliminess – Mould makes kimchi viscosity decrease and turn slimy.

Smell

Putrid – Foul, pungent odor indicates spoilage.
Rotten – Smells like decomposition.
Ammonia-like – Sharp, urine-like smell means mould.

Taste

Bitterness – Mould produces a bitter taste.
Mustiness – Earthy, muddy flavour associated with mould.

Types of Mould

Black – Black mould is always toxic. Toss immediately!
Blue or green – Also hazardous and potentially deadly. Do not eat!
White – Powdery white kahm yeast is generally safe if removed.
Orange, pink, other colors – Uncommon on kimchi but still unsafe to eat.

When unsure about fuzzy spots on your kimchi, apply the sniff test. If it passes, taste a tiny sample. At the first hint of foulness, get rid of the entire batch. Don’t risk your health!

Salvaging Kimchi with Slight Mould Growth

Finding kimchi mould doesn’t always mean total failure. Here are some guidelines for salvaging kimchi if you catch the mould early:

Small localised spots of mould growth may be cut out along with 2 inches of surrounding kimchi.
With extensive mould growth throughout, it is safest to discard the entire batch.
When in doubt, throw it out! Don’t risk eating mouldy kimchi.

Starting over with a fresh kimchi recipe is heartbreaking but critical to avoid toxins produced by mould. Use your newfound knowledge to ferment your next batch flawlessly mould-free.

Mould – The Ultimate Kimchi Catastrophe?

Mould might seem like the ultimate kimchi catastrophe, but armed with the right fermentation practices, you can avoid this fuzzy foe. Limit air exposure, control temperatures, and foster healthy fermentation using the proper amount of salt.

Monitor your kimchi closely during the fermenting process. At the first signs of mould, troubleshoot to identify the root cause and make adjustments. Discard any kimchi with black, blue-green or extensive mould contamination. With early intervention, white moulds can sometimes be removed.

It takes patience and vigilance, but you can master the art of mould-free kimchi. Say bye to fuzzies ruining your fermented creations! Now go forth and start whipping up big batches of probiotic powerhouse kimchi without fear of mould. Your gut will thank you!