Honey’s stable nature is due to a variety of factors and characteristics. Its unique chemical composition makes it one of the most resilient foods.
The Science Behind Honey’s Eternal Shelf Life
Honey is hygroscopic, meaning that it absorbs water from everything, including air. Honey’s ability to attract water molecules is due to it being composed out of mostly sugar. That being said, sugars are hygroscopic — they don’t contain a lot of water in their natural state. Moreover, honey is made up of about 80% sugar, which is essential in inhibiting the growth of many types of microbes, including fungi and bacteria.
Since honey is mostly sugar, it doesn’t contain much water. What’s great about this is that bacteria cannot thrive in a low-moisture environment. Honey’s high concentration of fructose and glucose makes it resistant to bacteria, thus giving it its long shelf life.
The hygroscopic properties of honey create an environment that is inhospitable to bacteria and other spoil-ready organisms. They can’t survive long enough to have a chance to spoil the honey. This is an important feature of honey’s longevity.
Moreover, due to the osmotic imbalance between bacterial cells and the high-concentrated surroundings, the bacterial cell loses all the water from the cytoplasm. This process — called plasmolysis — kills off all bacteria. This is honey’s secret to not spoiling!
Being that there’s no free water for microbes and molds to thrive in, honey has often been used for a variety of medicinal purposes. Its high viscosity and antibacterial properties make it the perfect barrier against infections, especially for wounds. Medicinal honey was regularly used by the Sumerians and the Ancient Egyptians in ointments and other treatments. It works as a kind of natural band-aid.
Highly Acidic and Antibacterial
Aside from its hypertonic and hygroscopic properties, honey is also acidic and antibacterial. Its low pH value of around 4 creates an environment that’s too acidic for most microbes. This sets it apart from other sugars. Also, when honey absorbs moisture, it naturally produces hydrogen peroxide, which acts as an antibacterial agent. This makes it difficult for bacteria to survive and spoil the honey, even if improperly stored.
Bees play an essential role in contributing to the low water content of honey. They flap their wings to dry out the nectar. When bees regurgitate the nectar they collected into the hive, the worker bees begin breaking down the sucrose into fructose and glucose. Keep in mind that nectar is high in water — about 60 percent. Flapping their wings does an excellent job of drying out the nectar. This helps keep the moisture level low and prevents harmful organisms from multiplying.
An enzyme called glucose oxidase is secreted during this process. It comes from the stomachs of bees. Bees vomit nectar into honeycombs, so this enzyme is transferred with the nectar. This enzyme is responsible for breaking down glucose into gluconic acid and hydrogen peroxide.
Why is this important? How does it relate to honey having an eternal shelf life? Well, gluconic acid is the main reason for the acidic nature of honey. The presence of gluconic acid makes the environment lethal for bacteria and microbes. Whereas, hydrogen peroxide is the main compound responsible for the antibacterial properties of honey. It works towards preventing microbial growth that would otherwise spoil honey.
Keep in mind, although honey is resilient to spoiling, if the water content gets high enough, yeast can ferment the honey and create alcohol. This could be considered spoiled honey. However, it depends on the type of yeast. For example, good yeast can create mead! If your honey is protected and well-sealed, it can remain edible for thousands of years.
Honey’s appearance and texture can change with time. Instead of being golden and clear, you’ll notice that it may begin to look cloudy and somewhat grainy. If left long enough, honey will turn hard and white. When it begins to change in color and consistency, this means that the honey has started the crystallization process. This happens when some of the glucose content begins to crystallize.
When honey crystallizes, this does not mean that it has gone bad. It’s still safe to eat. It’s just a bit granulated. While it might not be the most pleasant texture, it is still edible. With time, honey can darken and lose some of its aroma.
Also, keep in mind that some commercial honey that you would find in your grocery store may never crystallize. This is because it’s been processed to prevent natural crystal formations. However, if the honey is raw and natural, it will crystallize more frequently. This is due to the pollen and enzymes that were not filtered out due to the lack of pasteurization.
Crystallization is a good sign. It means that your honey is natural and pure. It’s normal that it changes in texture and appearance with time and temperature change. Processed honey doesn’t stand the test of time like raw and unfiltered honey.
What to Do if Honey Crystallizes?
Heat It Up
Don’t toss it; heat it up. You can do this by microwaving it in 30-second increments or placing the honey in a glass jar and then placing it in a container of heated water. Just make sure you don’t bring the honey to a boil. This will have a negative effect on the flavor. The key to removing crystals is using slow and indirect heat.
Store at Room Temperature
Keep honey stored and sealed in a dry place like your cupboard or pantry at room temperature conditions.
Honey crystallizes faster at temperatures between 50 and 59 degrees Fahrenheit. It resists crystallization best at temperatures above 77 degrees Fahrenheit.
What About the Expiration Date?
Manufacturers of honey place an expiration date on every jar of honey — just like all other products. However, pure honey does not spoil if stored and sealed properly. The expiration date is more of an indication of how long the contents of the jar should be of the best quality. After that specific date, the honey may begin to deteriorate and change in aroma and texture.
However, keep in mind that this applies to processed or pasteurized honey products. Honey will remain edible after the expiration date but might not taste as great as a new jar of honey. Raw honey, as long as stored in a dry and cool place, will never spoil.
If you’re worried about the state of your honey, smell it. If it smells bad, it probably is. Honey will go rancid if left unsealed in a humid environment.
Harmful to Infants
Although honey doesn’t spoil if stored properly, it can be harmful to a child, especially if they’re under a year old. Honey is safe for adults and older children.
Honey sometimes can contain spores of a microorganism called Clostridium botulinum. This can be harmful to infants because their gastrointestinal tract hasn’t developed enough to process these spores. In rare cases, babies can develop infant botulism, which damages the nervous system and can cause paralysis and even respiratory failure.
It’s best to avoid feeding your young child any form of honey until their gastrointestinal tract fully develops.
It Can Be Contaminated
Honey is not one hundred percent, bacteria or microbe-free. There are some microbes that are naturally present in honey. These microbes include bacteria, yeast and even molds. They can come from the pollen or nectar or from the bees’ digestive tract, as discussed in the above sections.
Aside from these sources, there are many other external sources that can infect honey with microbes. This can be from dust, air, dirt or flowers. Due to honey’s natural antimicrobial properties, these microbes are found in small quantities. Again, due to the presence of hydrogen peroxide and glucose oxidase, these organisms don’t have the chance to multiply.
What does this mean for your health or food safety concerns? It means that, yes, honey can sometimes be contaminated. But, due to the antimicrobial characteristics, the harmful organisms are unable to multiply and thrive. So, it’s not a health concern at all, nor does it contribute to the overall spoiling of honey.
Keep in mind, as discussed in the above section, spores of the toxic organism, C. botulinum are found in 5–15 percent of honey samples. Don’t be alarmed; the concentration of this is very low. For adults or mature children, the presence and consumption of C. botulinum are harmless. Just keep it away from children under one year of age.
Apart from natural contaminants, other external factors can result in secondary contamination. This can happen during the processing of honey in a factory, for example. So, although pure honey itself won’t go bad on its own, if exposed to outside sources, it can indeed be contaminated. However, it will remain safe to consume.
When Honey Becomes Toxic
Honey can be contaminated by toxic compounds anywhere in the honey-making process. From the nectar to the processing and aging, there are numerous ways honey can become harmful and unsafe to consume.
So far, we’ve discussed honey being naturally contaminated or being contaminated by an external source but overall, still being safe to consume. However, this doesn’t mean that you should trust all the honey you come across. There are cases where honey can contain toxic and harmful compounds that should raise health concerns.
These are rare cases but need to be addressed. When bees collect nectar at the beginning of the honey production journey, they visit a wide variety of flowers and plants. Sometimes, the toxins present in these plants is transferred into the honey, contaminating it from the very start. If you’re consuming this product as pure, raw honey, you could get very sick.
A famous example of this is mad honey. This is caused by grayanotoxins in nectar from Rhododendron ponticum, as an example. Nectar extracted from this plant produces nectar that can be harmful and cause a variety of health problems. These can be serious afflictions, ranging from dizziness, nausea and high blood pressure.
Yes, the presence of these toxic compounds is rare, but is still very much something you should at least be cognizant about. Honey itself, when not contaminated, can have an eternal shelf life, but when tampered with accidentally or if the source itself is toxic, honey can be dangerous and will spoil.
Moreover, there’s another substance called hydroxymethylfurfural (HMF), which is produced during the processing and aging of honey. MHF can have serious effects on your health. It can permanently damage cells and DNA.
This is an example of how secondary external forces can upset the natural protective forces put in place by the antimicrobial properties of honey.
Honey Can Be Tampered With
Unfortunately, there can be foul play when it comes to the processing and production of honey. Honey is difficult to produce and takes a lot of time and effort to reach the final product. This makes it susceptible to adulteration, especially for honey that’s produced on a wide commercial level.
Adulteration can take many forms. One of the most common ways of tampering with honey is adding artificial sweeteners to the final product. Of course, this is intended to increase the volume and the profit margin. So, keep in mind, when purchasing inexpensive honey in the supermarket that some manufacturers do add non-honey fillers to their product.
During the initial production phase, the bees themselves can be fed with sugar syrups. Beekeepers or honey producers can also mix these syrups into the finished product. This would mean that your store-bought honey will spoil as it isn’t pure, raw honey.
Also, beware that big companies will often harvest honey before it’s reached its ripe state. Unripened honey has higher water content. This water disrupts the natural balance that protects the honey and throws off all those hygroscopic properties we discussed above.
Honey’s unique composition and chemical properties give it its eternal shelf-life. Its low pH level, low moisture content and the presence of hydrogen peroxide work together to prevent bacteria and microbes from spoiling it. These properties all work in perfect harmony to almost form something like a perfect shield against toxic and harmful microorganisms.
Its special properties help it last for decades or even centuries. It’s resilient to bacteria and other spoil-ready microorganisms. As long as it is stored in a cool, dry place in a sealed container, it will never spoil. Yes, it may change in texture or color, but — as long as it’s raw and unfiltered — it will always remain edible.