The expiration date of food is something that we see on a day to day basis, and it is put in place to let us know how long certain food can last. Usually, that date doesn’t represent the date when the food is unsafe to eat but more the date until when that item is of the best quality. Some food can last for months, while other types of food are edible for only a few days. Usually, natural and fresh food, such as vegetables and fruits, can’t last long, while heavily processed food can last for months. Honey is a natural sweetener made by honey bees, so it raises a question of ‘does honey expire?’. Some say that honey can never expire, but is that true?
Honey has a very long history in human culture. It is one of the oldest sweeteners consumed by humans whose use is recorded as far back as 5,500 BC. You have probably heard of ancient jars of honey found in Egyptian tombs, with honey still good to eat as the day the jars were sealed. Since humans have used honey since ancient times, there are many such findings of honey remains.
The oldest known honey was found in Georgia on the inner surface of clay vessels from an ancient tomb, which dates between 4,700 and 5,500 years. In ancient Georgia, honey was buried with a person for their journey into the afterlife.
Ancient India has documented the spiritual and therapeutic use of honey in both Ayurveda and Vedas texts, which are dated to at least 4,000 years ago. The Maya used honey for culinary purposes, and regarded bees sacred animals.
Even ancient Greeks were fond of honey and bees. In 594 BC the beekeeping around Athens was so popular that Solomon had to pass a law stating that new hives must be placed at least 90 meters (300 feet) away from hives already present. Their beekeepers didn’t hesitate to move the hives long distances in order to increase honey production.
Stories like these have led many people to believe that honey can last forever, and judging by such evidence it’s safe to assume that honey can last a long time. But why can honey last so long?
The answer to this question hides in a few special properties, which include low moisture content, high sugar content, acidic nature, and antimicrobial enzymes. In this section, we will go into more detail about those properties and how they help honey last so long.
High sugar content and low moisture
Honey is made of approximately 80% sugar and no more than 18% of water, which can inhibit the growth of microbes such as bacteria and fungi. The exact ratio of sugar and water depends on the bee species, weather, plants, and processing.
The osmotic pressure in honey is very high because of high sugar content, which causes drying out of microbes. Water flows out of them and stops their growth and reproduction.
Even though 18% of water content seems like a lot, the water in honey has a very low activity. Low water activity means that water molecules interact with sugars in such a way that microorganisms cannot use them. The result of this is that fermentation or breakdown of honey cannot occur.
Moreover, honey is dense so oxygen cannot easily dissolve into it, which prevents many types of microbes from reproducing or growing.
Honey is acidic
The honey is quite acidic with its pH ranging from 3.4 to 6.1, and the main reason for this is the presence of gluconic acid. The gluconic acid is produced during nectar ripening.
Previously, it was thought that the acidity of honey is what prevents microbial growth, but studies have shown that is not true for most microbes. The growth of some bacteria, such as E. coli, Streptococcus, and Salmonella, is hindered in an acidic environment.
This property is one of the reasons why honey is used on burn wounds and ulcers to prevent infections. The acidity makes honey effective in killing certain types of bacteria.
Honey bees produce enzymes which suppress bacterial growth
The enzyme in question is glucose oxidase, which bees secrete into the nectar during honey production. This helps preserve the honey. Here you can learn more about how bees make honey.
While honey ripens, glucose oxidase produces hydrogen peroxide and converts sugar into gluconic acid. The hydrogen peroxide prevents the growth of microorganisms and contributes to the antibacterial properties of honey.
However, despite having antimicrobial properties honey can still go bad. In the next section, we will explore why it can happen.
Even though honey can last a long time, under certain circumstances it can go bad.
Honey can contain toxic compounds
For honey production bees need to collect nectar from flowers, but this process can also transfer plant toxins into the honey. An example of this is “mad honey” which contains grayanotoxins from Rhododendron ponticum and Azalea pontica. Consuming honey produced from these plants can cause nausea, problems with blood pressure or heart rhythm, and dizziness.
Moreover, during processing and aging of honey a substance known as hydroxymethylfurfural (HMF) is produced. Some research has found that it can have negative effects on health, such as damage to DNA and cells, but other studies also report some positive properties. These properties are anti-inflammatory, anti-allergy, and antioxidative properties.
Honey might be adulterated
Since honey production is time-consuming and expensive, it has been the target for adulteration for years. What we mean by adulteration is adding cheap sweeteners to increase volume and reduce cost.
Moreover, the cost is sometimes also lowered before honey production even begins. This is done by feeding the bees with sugar syrups from cane, beet, and maize sugar.
Also, the process of producing honey is sometimes sped up by harvesting it before it’s ripe, which means that the water content is higher than it should be (can be over 25%). Such high water content means that there is a higher risk of fermentation.
Honey may be contaminated
The honey naturally contains molds, yeast, and bacteria, but due to antimicrobial properties they are usually found in small numbers.
However, 5% - 15% of honey contains spores of the neurotoxin C. botulinum, which are harmless for adults but can be dangerous for babies under one year old. It can cause infant botulism, which can cause respiratory failure, paralysis, or damage to the nervous system. Since you cannot know which honey has it, it’s best to avoid giving honey to babies.
Honey may be stored incorrectly
Incorrect storage of honey can reduce its antimicrobial properties, contaminate it, or cause fermentation. Open containers can allow contamination with microbes and an increase in water content, which increases the risk of fermentation. Also, heating honey can degrade it. If you want to learn more about what heat does to honey go here.
Honey can crystalize and degrade
Crystallization of honey is a natural process because it contains more sugars than can be dissolved, but that doesn’t mean that crystallized honey has gone bad. You can recognize crystallization by the opaque color of honey and graininess. By itself it is not dangerous for honey, but crystallization increases water, which increases the risk of fermentation.
Moreover, honey stored for a long time might start to lose its aroma and flavor, and may become darker. This isn’t a health risk but can change the appeal and taste of honey.
Honey can last indefinitely, but certain things can cause it to go bad. The main reason honey can go bad is if the water content is too high. High water content enables yeast and microbes to grow and cause fermentation.
You can easily tell if there’s something wrong with the honey when you smell or taste it. If the taste doesn’t resemble typical honey taste or you can taste some alcohol, then don’t use that honey. Also, honey gone bad is often more liquidy than usual because of higher water content.
Due to its properties, honey can stay fresh for years. But under certain circumstances it can go bad or lose some of its properties. Even though yeasts, molds, and bacteria usually cannot reproduce much, honey can still be contaminated. Most of the cases of honey going bad are due to improper storage, so make sure to store your honey properly. The best place for honey is in an airtight container in a dry, cool place. When buying honey don’t be afraid of those jars with crystallized honey, it’s just a natural process. However, be careful when buying honey in the store. Unfortunately, honey found in stores is often adulterated, so it might even be bad for you because of all the added sugar. The best choice when it comes to honey is to buy raw honey from a trusted beekeeper so you can reap all the benefits of honey. By purchasing honey from reputable places and storing it correctly, your honey can last for many years.