Why is my honey fermented? A guide to preventing it

Archaeologists found edible honey in King Tutankhamun's tomb, proving honey can last forever, but only under the right conditions. So, why is my honey fermented? This happens when wild yeast, naturally present in honey, becomes active due to a high moisture content, leading to a sour, bubbly, and off-tasting product.

Quick Summary

Fermentation in honey is caused by osmophilic yeasts acting on sugars when the moisture content is too high, typically above 18%. This can occur due to improper harvesting, storage conditions, or crystallization. The process results in a sour flavor, off-smell, and a bubbly texture. Correct storage and handling are key to preventing it.

Key Points

• High Moisture is the Cause: Fermentation in honey is triggered by osmophilic yeasts when the moisture content rises, typically above 18%.

• Crystallization Increases Risk: As honey crystallizes, moisture concentrates in the remaining liquid, creating ideal conditions for yeast to become active.

• Visible Signs Include Bubbles and Foam: You can identify fermentation by a sour smell, an off-taste, and a bubbly or foamy texture on the surface of the honey.

• Prevent with Proper Storage: Store honey in a cool, dark, and dry place in a tightly sealed container to prevent moisture absorption.

• Fermented Honey is Safe to Eat: Accidental fermentation does not make honey unsafe, but it does change the flavor profile to be sour or tangy.

• Repurpose with Recipes: Fermented honey can be used in cooking, baking, marinades, or to make mead, turning a flaw into a unique ingredient.

The Science of Honey Fermentation

Honey's remarkable shelf life is due to its low moisture content and high sugar concentration, which creates an environment hostile to most microorganisms. However, certain types of yeast, specifically osmophilic yeasts, are tolerant of these conditions and are the culprits behind fermentation. These yeasts are naturally present in honey, having been introduced by bees during foraging on flowers.

The fermentation process begins when the moisture level in the honey increases, diluting the sugar and creating a more hospitable environment for the yeast to grow and multiply. As the yeast digests the sugars, it produces alcohol and carbon dioxide gas. In a sealed container, this gas can cause pressure to build up, sometimes to dangerous levels, and results in the characteristic bubbles or foam. The alcohol can then be converted into acetic acid (vinegar) in the presence of oxygen, which gives the honey its sour taste and pungent smell.

Why Honey's Moisture Content Matters

Bees naturally ripen nectar by fanning it with their wings to evaporate excess water, aiming for a moisture content below 18%. When this process is incomplete, the honey is 'unripe' and more susceptible to fermentation. Several factors can contribute to a high moisture level in harvested honey:

• Harvesting uncapped frames: If honey is harvested before the bees have capped the cells with wax, its moisture content is likely too high.
• High humidity: Harvesting and extracting honey in a humid environment can cause the honey to absorb moisture from the air.
• Improper storage: Storing honey in a container that is not airtight or is in a humid location allows it to absorb ambient moisture over time.

The Role of Crystallization

Crystallization, or granulation, is a natural and normal process for honey. However, it is a significant precursor to fermentation. When honey crystallizes, the glucose separates from the liquid, leaving a higher concentration of moisture in the remaining liquid portion. This provides the perfect condition for the dormant osmophilic yeast to activate and begin fermenting the honey. The crystallization rate depends largely on the floral source, as honeys with a higher glucose-to-fructose ratio crystallize faster.

Factors Influencing Fermentation

Fermentation is not inevitable and is determined by a combination of factors. The risk increases with:

• High moisture content (above 18% is high risk)
• High ambient storage temperatures (yeast is most active between 10°C and 27°C)
• High levels of osmophilic yeast spores
• The honey has granulated or crystallized

Comparison of Fermented vs. Non-Fermented Honey

Feature	Non-Fermented (Good) Honey	Fermented Honey (Accidental)	Purposeful Honey Ferment (Mead, Garlic)
Appearance	Clear, viscous, or smoothly crystallized.	Bubbles, foam on top, cloudy appearance, separated layers.	Bubbles, thinner consistency, may have added ingredients.
Smell	Sweet, floral, and aromatic.	Sour, acidic, slightly alcoholic, or yeasty odor.	Dependent on ingredients, often tangy, complex, or bready.
Taste	Purely sweet, reflective of its floral source.	Sour, tangy, and unpleasant.	Sweet and sour, spicy (garlic), or reminiscent of wine (mead).
Texture	Smooth, thick, and syrupy, or creamy if crystallized.	Foamy, runny, and sometimes gritty due to crystals.	Thinner, more liquid, less viscous.
Safety	Considered indefinitely shelf-stable and safe to eat.	Safe to consume, though not ideal for flavor.	Safe when prepared correctly. Do not feed to children under 1 year.

How to Prevent Honey from Fermenting

Preventing fermentation primarily involves managing moisture and storage conditions. By following these best practices, you can ensure your honey remains in perfect condition for years to come.

1. Harvest Ripe Honey: Beekeepers should only harvest frames that are at least 90% capped by the bees, indicating a low moisture content.
2. Use a Refractometer: For hobbyists and commercial producers, a refractometer is a key tool for measuring moisture content. The goal is to be below 18%, or even better, 17%.
3. Ensure Proper Storage: Store honey in a clean, dry, and airtight container. Glass jars with tight-fitting lids are ideal for preventing moisture absorption.
4. Control Temperature: Keep your honey in a cool, dark place, ideally below 10°C (50°F), to slow or stop yeast activity. Refrigeration will halt fermentation entirely.
5. Re-liquefy with Care: If your honey has crystallized, re-liquefy it by placing the container in a bowl of warm water (not over 40°C or 95°F) to avoid destroying beneficial enzymes.
6. Avoid Humid Environments: Do not store honey in high-humidity areas like near a stove or above a dishwasher, as this increases moisture exposure.

What to Do with Fermented Honey

If your honey has already begun to ferment, it is still safe to eat, though the flavor and texture will be altered. You cannot reverse fermentation once it has started. However, you can make the best of it with a few creative options.

• Use it in Cooking and Baking: The sour, tangy flavor of fermented honey can add a unique dimension to sauces, marinades, and baked goods. Its flavor is particularly well-suited for barbecue sauces or glazes for meat.
• Make Mead: Fermented honey is the primary ingredient for mead, a honey wine. You can control the process by adding specific yeasts for a more predictable result.
• Create Fermented Garlic Honey: A popular remedy involves fermenting garlic cloves in honey. The fermented honey acts as a probiotic-rich base, and the mixture develops a delicious, savory-sweet flavor.
• Add it to Hot Beverages: The tangy taste can be a pleasant addition to tea or warm water, especially during cold and flu season, as fermentation can increase probiotic content.

Conclusion

While a jar of honey can theoretically last indefinitely, fermentation is a natural process that can occur if the honey is exposed to excess moisture and stored improperly. The combination of naturally occurring osmophilic yeast, moisture content above 18%, and warmer temperatures is the recipe for unwanted fermentation. By taking simple preventative measures like proper storage and harvesting ripe honey, you can easily avoid this issue. Should you find yourself with a fermented batch, it's still safe to use and can be repurposed creatively in cooking or for making mead, so nothing has to go to waste. Understanding the science behind honey's natural state empowers you to manage and appreciate its journey from hive to table.

An excellent and authoritative guide on the topic is the USDA's Beekeeping in the United States, which offers deep insights into honey management.

Frequently Asked Questions

What is the primary cause of honey fermentation?

The primary cause is the activity of osmophilic yeasts that are naturally present in raw honey. They become active and consume the honey's sugars when the moisture content rises above the ideal level (around 18%).

Is fermented honey safe to consume?

Yes, accidentally fermented honey is generally safe to eat. While the flavor will be different—sour, tangy, or yeasty—it is not harmful. However, it may not be suitable for selling as premium honey.

Can I stop honey from fermenting once it has started?

You cannot reverse the fermentation process once it has begun. You can, however, halt further fermentation by refrigerating the honey, as cold temperatures slow yeast activity.

How can I tell if my honey is fermenting?

Look for signs such as foaming or bubbling on the surface, a runnier consistency, a sour or yeasty smell, and a tangy or off-flavor. This is often accompanied by crystallized honey.

Does crystallization mean my honey will ferment?

Crystallization itself is a natural process, but it is a precursor to fermentation. The separation of glucose from the water increases the moisture concentration in the liquid portion, which can trigger dormant yeast.

What can I do with fermented honey?

You can use fermented honey in cooking, such as in barbecue sauces or glazes, or for making mead, a honey wine. It's also popularly used for making fermented garlic honey, an immune-boosting remedy.

How do beekeepers prevent honey from fermenting?

Beekeepers prevent fermentation by ensuring they only harvest 'ripe' honey from capped frames, minimizing moisture exposure during extraction, and storing it in airtight containers in a cool, dry place.