Nutrition Diet: What temperature kills yeast in honey?

November 6, 2025 •

4 min read

According to food science research, heating honey to approximately 145°F (63°C) for 30 minutes is a standard pasteurization process designed to kill the osmophilic yeasts responsible for fermentation. This guide explores exactly what temperature kills yeast in honey and how this process impacts the nutritional profile of this natural sweetener for your diet.

Quick Summary

Heating honey through pasteurization kills yeasts that cause fermentation and delays crystallization, but this process also degrades beneficial heat-sensitive compounds and alters its flavor profile.

Key Points

Yeast Destruction Temperatures: Standard pasteurization involves heating honey to at least 145°F (63°C) for 30 minutes, or a higher temperature for a shorter time, to kill fermenting yeast cells.
Nutritional Loss: The heat used to kill yeast also degrades beneficial enzymes (diastase, glucose oxidase, invertase) and reduces antioxidant compounds like polyphenols and flavonoids.
Raw vs. Pasteurized Honey: Raw honey is unheated and minimally filtered, retaining its full nutritional profile, while pasteurized honey has reduced nutrients but a longer shelf life and a smoother texture.
Fermentation and Moisture: Yeast-driven fermentation in honey is triggered by increased moisture content (above 18%), which can occur naturally after crystallization.
Infant Botulism Risk: The temperatures used for pasteurization do not kill botulism spores, so honey should never be given to infants under one year old, regardless of whether it is raw or pasteurized.
Preserving Nutrients: To maintain honey's nutritional benefits, use raw honey in unheated applications or gently warm it below 104°F (40°C) to prevent crystallization.
Flavor Alteration: Heating honey can cause the loss of delicate volatile compounds, resulting in a milder and less complex flavor profile compared to raw honey.

The Role of Yeast in Honey

Honey, in its raw and natural state, contains trace amounts of osmophilic yeasts, which are tolerant to high sugar concentrations. Under normal conditions, honey's high sugar content and low moisture prevent these yeasts from becoming active. However, if the honey's moisture content rises above approximately 18%—often a result of crystallization, where glucose sugars separate from the watery fructose solution—the yeasts can become active and initiate fermentation. Fermentation in honey results in the formation of alcohol and carbon dioxide, leading to a sour taste and a bubbly, foamy texture. While fermented honey is generally safe to consume for adults, it is often viewed as a quality defect by commercial producers, which is why pasteurization is a common practice.

The Pasteurization Process: Time and Temperature

To prevent fermentation and achieve a consistent product with a longer shelf life, honey is often pasteurized. The temperatures and exposure times required to kill yeast can vary, balancing the need for sterilization against the desire to preserve flavor and beneficial compounds. Different methods exist:

Low-Temperature, Long-Time (LTLT): Heating honey to around 145°F (63°C) and holding it for approximately 30 minutes is a common method for pasteurization.
High-Temperature, Short-Time (HTST): Some commercial operations use flash heating, quickly heating the honey to 160°F (71°C) or higher for a very short duration and then rapidly cooling it. This method aims to kill yeast while minimizing heat damage.
Flash Heating for Filtration: In some cases, honey is heated to around 160°F (71°C) to kill yeast cells and also to reduce its viscosity, allowing for easier filtration and bottling.

The heat treatment effectively destroys the yeast cells, preventing future fermentation. However, these temperatures also impact the honey's delicate composition, altering its taste, color, and nutritional value.

The Impact of Heat on Honey's Nutritional Value

While heating successfully kills yeast, it comes at a nutritional cost. The natural enzymes and antioxidants present in raw honey are particularly vulnerable to heat degradation.

Enzymes

Diastase: This enzyme, which helps break down starch, is a key indicator of honey's freshness and heat exposure. Research shows that heating honey above 118°F (48°C) for extended periods can significantly reduce diastase activity.
Glucose Oxidase: This enzyme produces hydrogen peroxide, contributing to honey's natural antibacterial properties. It begins to degrade at lower temperatures, with activity reduced by up to 30% when heated to 130°F (55°C) for 15 minutes.
Invertase: Responsible for converting sucrose into glucose and fructose, invertase is highly heat-sensitive, with its activity measurably impacted by prolonged exposure to temperatures as low as 95°F (35°C).

Antioxidants and Other Compounds

Polyphenols and Flavonoids: These beneficial antioxidant compounds, found in varying levels depending on the honey's floral source, can be reduced by 14–30% after heating to pasteurization temperatures.
Flavor Compounds: Heating can alter honey's nuanced, floral flavor profile. Volatile aroma compounds are lost, resulting in a more uniform but less complex taste.

Raw Honey vs. Pasteurized Honey: A Comparison

The choice between raw and pasteurized honey often depends on individual priorities, whether they prioritize maximum nutrient content or a longer, more convenient shelf life.


Feature	Raw Honey	Pasteurized Honey
Processing	Minimally filtered, unheated (kept below 104°F/40°C)	Heated (145-170°F or 63-77°C) and often ultra-filtered
Nutritional Value	Retains enzymes, antioxidants, and pollen	Reduced content of heat-sensitive enzymes and antioxidants
Texture	Prone to natural crystallization over time	Remains liquid for longer periods, with a smooth, consistent texture
Flavor	More complex, floral, and distinct flavor profile	Milder, less complex flavor due to loss of volatile compounds
Appearance	Often cloudy due to pollen and wax particles	Clear and translucent due to high heat and fine filtration

Choosing Honey for Your Diet

Understanding the effects of heat on honey's composition allows for more informed dietary choices. If preserving the maximum nutritional benefits is your goal, consuming raw or minimally processed honey is the best option. To minimize nutrient loss, use raw honey in recipes that don't involve high heat or add it to warm (not hot) beverages after they've cooled.

How to Safely Decrystallize Raw Honey at Home

For those who prefer raw honey but encounter natural crystallization, gentle heat can be used without damaging the beneficial compounds. Instead of microwaving or boiling, try these methods:

Warm Water Bath: Place the honey jar in a pot of warm water. The water temperature should not exceed 100°F (38°C). This slow, gentle heating will return the honey to a liquid state while preserving its enzymes.
Use a Dehydrator: A food dehydrator set to a low, consistent temperature can be a reliable tool for decrystallizing honey over several hours.
Monitor Temperature: Use a kitchen thermometer to ensure the honey's temperature stays below 104°F (40°C), the commonly accepted threshold for raw honey.

Conclusion

The temperature required to kill yeast in honey, which typically ranges from 145°F to 170°F (63°C to 77°C) during pasteurization, effectively prevents fermentation and extends shelf life. However, this heat treatment comes at the expense of valuable, heat-sensitive nutritional compounds, including enzymes and antioxidants. Raw honey, by contrast, retains its full complement of nutrients but is susceptible to natural crystallization and fermentation over time. For those prioritizing a nutrient-rich diet, opting for raw honey and using gentle, low-heat methods for decrystallizing is the most beneficial approach. Ultimately, the best choice depends on your dietary goals and what you value most in this versatile natural sweetener.

For further information on honey processing and regulations, you can consult resources like the National Honey Board.

Frequently Asked Questions

Yeast in honey can be killed during pasteurization with various time-temperature combinations. A common method is heating to about 145°F (63°C) for 30 minutes, but some methods use higher temperatures like 160-170°F (71-77°C) for a very short duration.

No, pasteurization does not remove all nutrients, but it does significantly reduce the levels of heat-sensitive compounds. Enzymes, antioxidants (like flavonoids and polyphenols), and volatile flavor compounds are particularly vulnerable to degradation from heat.

Yes, fermented honey is generally safe for consumption for adults. The fermentation process is caused by harmless yeasts and results in a change of flavor and texture, not a health risk.

Honey ferments when its moisture content rises above 18%, causing the osmophilic yeasts naturally present in it to become active. This often happens after honey crystallizes, which separates some of the water and increases the moisture level of the liquid portion.

Signs of fermented honey include a distinct alcoholic or sour smell, a foamy or bubbly appearance on the surface, and a changed, more liquid consistency.

Honey, whether raw or pasteurized, can contain dormant spores of Clostridium botulinum. An infant's immature digestive system can allow these spores to grow and produce a toxin, causing infant botulism. Pasteurization does not kill these resistant spores.

To prevent fermentation, store your honey in a tightly sealed container in a cool, dry location. This keeps the moisture content low and inhibits yeast activity.