Moisture Content Of Honey

Moisture Content Of Honey
Moisture Content Of Honey

Have you ever wondered how much moisture is in honey? The truth is that the exact amount varies depending on a given country’s food standards and the source of nectar from which the honey is made. However, in general terms, a moisture content between 17% – 21% is internationally accepted. 

Moisture Content Of Honey By Country

U.S.A (Grade A Or B)Canada (Canada No. 1 Grade)United KingdomAustralia/New Zealand
Moisture content of honey 18.6% or less17.8% or less20% or less21% or less
Moisture content of honey according to country

Every country has different food standards which are set by the relevant Government bodies. These food standards typically outline the accepted water level of honey. We took a look at a few different countries to give you an example – the U.S.A, Canada, the United Kingdom, Australia, and New Zealand. 

In the U.S.A, honey follows a grading system. There are four grades: A, B, C, and ‘substandard.’

According to the United States Department of Agriculture (USDA) standards, for honey to be considered Grade A or B, it must have a moisture content of 18.6% or less. 

Honey with a moisture content between 18.6 – 20% is considered Grade C. Anything with more than 20% moisture is considered substandard. 

In Canada, honey that is determined to be ‘Canada No. 1’ (the highest grade) must contain no more than 17.8% moisture, or no more than 18.6% moisture if the container bears the word ‘pasteurized.’

Honey with a moisture content between 18.6 and 20% is graded Canada No. 2. Anything with a moisture content of 20% and above is graded Canada No.3.

In the United Kingdom, the grading system is different. The Honey (England) Regulations 2015 simply state that all honey must have moisture or less than 20% – except for heather honey, which can have a moisture level of up to 23%.

Food standards in Australia and New Zealand are very similar to the UK, determining less than 21% moisture content as acceptable.  

How Moisture Content In Honey Is Reduced By Bees

The way bees make honey is quite fascinating and will explain where the moisture of honey comes from. 

Nectar is the raw material from which honey is made. Nectar is made up of varying degrees of 3 types of sugars –  sucroseglucose, and fructose. Foraging bees collect nectar from the flowers they visit and store it in a unique organ known as a honey stomach or sac. 

Honey bee flying towards a flower

In the stomach, an enzyme called invertase reacts with the nectar, which breaks down the sugars and converts them into a solution of glucose and water. This process is called inversion. 

Once the sacs are full, the bees return to the beehive, where the teamwork begins. The solution is passed mouth-to-mouth from one bee to another until the moisture in the solution is reduced from around 70% to 20%. 

The last bee then regurgitates the nectar into a cell in the honeycomb. Bees then further reduce the moisture in the nectar by fanning their wings to make some of the remaining water evaporate before they cap it with beeswax. 

Another way bees promote moisture reduction in nectar is by keeping the temperature of the hive at around 93°F to 95°F (33.8°C to 36°C). This is another mind-blowing fact about bees – they are remarkable at regulating the temperature of their hive.

As the moisture evaporates from the nectar, it thickens and becomes honey. At this point, the water content is around 13-18%

Why Is The Moisture Level Of Honey Important?

You are probably asking yourself, why is the moisture level in honey so important? Why is it such a big deal for beekeepers since honey is supposed to ‘never spoil’?

And it’s true. One of the extraordinary properties of honey is its very long shelf life. However, this only happens when certain conditions are met – and ideal moisture level is one of these.

Honey with a high water content has a greater risk of fermentation. 

How Does Fermentation Happen?

Honey goes through fermentation when the yeast spores in it react with excess moisture. 

Now, while the idea of yeast in honey doesn’t sound too appetizing, this is a natural occurrence. The bees bring yeast spores from flowers, so it’s almost unavoidable.

The good news is that, without enough water, the yeast remains dormant. However, if the water content is higher than ‘ideal’, it’s a different story. 

The time it takes for a given jar or batch of honey to ferment will depend on the count of yeast spores and the moisture level it contains. 

The count of yeast spores can range from one spore per gram to tens of thousands of spores per gram. As you can probably imagine, honey with a low count of yeast spores will last longer without fermenting than one with a higher count. 

Honey Safety According To Moisture Content And Spore Count 

Moisture Content (%)Fermentation Risk
Less than 17.1Safe regardless of yeast count
17.1 – 18.0Safe if yeast count is less than 1,000 per gram
18.1 – 19.0Safe if yeast count is less than 10 per gram
19.1 – 20.0Safe if yeast count is less than 1 per gram
More than 20.0Always at risk
Source: http://extension.msstate.edu/publications/maximizing-honey-production-and-heating-honey

Why Worry About Moisture Instead Of Eliminating The Spore Count? 

Getting rid of all the yeast present in honey sounds like a much better approach than fixing the moisture content. That way, there’s a better guarantee that honey won’t ferment, right?

Sort of – in many cases, it’s not practical or even desirable.

To eliminate yeast, the honey must go through pasteurization, which requires heating honey at a certain temperature for a specific time. 

Commercial honey producers pasteurize their honey before putting it on the shelves to make sure it has the lowest risk possible of fermenting, among other reasons.

However, the temperature can also change the quality of honey. So, doing this without the proper equipment or in an uncontrolled way might end up changing some of the more desirable properties in your honey, like its taste. 

Plus, pasteurizing might be easy for a big company with commercial kitchens and labs that allow for controlled and sterile conditions – but not so much for the average backyard beekeeper. 

Further, given how popular raw honey has become, many beekeepers would prefer to keep their honey raw rather than pasteurize it, even if they had the equipment to do so. 

So, the preferred way to ensure honey doesn’t ferment is by making sure its moisture levels are low enough to keep the yeast inactive – which in some cases is easier to do than eliminating yeast altogether.

How To Make Sure Honey Has The Right Moisture Level

The best way to ensure your honey has the right amount of moisture is by monitoring and applying corrective measures before harvesting. 

Once the honey has been extracted, reducing the moisture level becomes more difficult. 

Honey is hygroscopic, meaning it will absorb excess moisture from the environment. 

Additionally, if you blow warm fans over jars of honey, only the layer on the surface would dry out – unless you have access to specialized equipment.

In short, if you find your honey has a higher than ideal water level, it is always easier to correct this before you extract the honey from the frames. 

Capped Honey Vs. Uncapped Honey

Want to make sure you extract the honey when it’s at the correct moisture level?

Sometimes the best answer is the simplest – extract the honey only when the cells are capped. 

Remember how bees make honey? The process of turning nectar into honey aims at reducing moisture because bees also need honey to last.

During the cold winter months, bees will rely on the sugary substance to maintain their energy levels and sustain life in the beehive without going out of the hive at low temperatures. Therefore, they cap the honey at the proper moisture level. 

Honey bees on frame of capped brood

Honey extracted from capped cells usually is at the desired 13% – 18% moisture level. There are cases when this doesn’t happen, for example, when the environment is too humid and the bees struggle to reduce moisture within the hive. 

However, if everything is working as it should, the water level in honey would be low, and taking honey from uncapped cells will increase the probability of having a high moisture content.

Measuring Moisture Content Before Harvesting

Besides extracting from capped cells, you can also use a refractometer to ensure the honey you will be extracting has the correct moisture level. This will give you a higher level of certainty that the moisture content of your honey is just right. 

For this, ensure you have a properly calibrated refractometer and take honey from a few cells in the frame you want to extract from. Here is one you can buy from Amazon that is inexpensive and has good customer reviews.

Compare the different readings you get so you can decide if the average moisture level is above or below the one you are aiming for. 

Using a refractometer will be especially helpful if you sell the honey as you want to meet your local regulations and food safety requirements to avoid any trouble (or unhappy customers).

Extracting As Soon As Possible 

Once you are happy with the moisture level of the honey you’ve measured, the best thing you can do is extract it and store it as soon as possible. 

As I mentioned earlier, honey will absorb the moisture in the environment, so the longer it stays exposed to a humid climate, the more water it will take in. 

Extracting it and storing it in closed containers or jars will prevent the absorption of excess moisture. 

If you live in a place where there is low humidity (50% or less), you won’t have to do this as quickly. 

How To Reduce Moisture Before Extracting The Honey

Suppose you took a few honey samples from your frames and show a higher moisture level than desired. What now?

There are a few ways you can bring down the moisture before extracting honey from the frames. 

For this, you need to be able to control the humidity and temperature of the room you will be extracting in – unless you already live in a dry climate. 

The moisture level in the honey will balance with the moisture in the air it is exposed to. That’s why having this variable under control is extremely important. 

This relationship can work for or against you. For example, if you leave honey exposed to a relative air humidity of 60% or less, your honey will release some of its water content and achieve a moisture content of 18.3% or below. This reduces the risk of fermentation almost completely. 

But suppose it’s exposed to higher relative air humidity. In that case, you risk ending up with honey that can ferment quicker due to high moisture. 

Relationship Between Relative Air Humidity And The Moisture Content Of Honey

Relative Air HumidityHoney Moisture Content
50.0%15.9%
55.0%16.8%
57.8%17.2%
60.0%18.3%
65.0%20.9%
70.0%24.2%
75.0%28.3%
80.0%33.1%

The best thing is to use a closed room, so it is easier to adjust the temperature and air humidity level. 

Also, these conditions will take longer to change in a larger space, so you might want to pick a room that is not too large but is still comfortable to work in.

You can use a hygrometer if you want to know with certainty the temperature and the humidity in your extraction room. 

At first, you might have to experiment a little to find the best method for you, given the available equipment and how much moisture your honey has. 

Sometimes it will be enough to just raise the temperature in the room for the relative humidity level to drop and, therefore, for the honey to release some moisture. 

On other occasions, you might need the help of a fan and a dehumidifier. 

Steps To Reduce The Moisture Content In Honey

Before you begin, you will need:

  • A hygrometer/thermometer.
  • A base to mount your supers – this can be anything that can raise the supers above ground level and keep them stable like two bricks. The idea is to allow airflow from underneath and also stack supers on top of each other. 
  • A small or large dehumidifier (depending on your room size) set between 35% to 45%
  • A heater set between 77 F and 86 F (25 C and 30 C). 
  • I also recommend a refractometer to measure the honey’s moisture and make sure it actually gets to the right level. 
  • Optional: a fan

Step By Step

  • Adjust the heater and dehumidifier, so the room reaches ideal conditions. Aim for the temperature to be at least 77 F (25 C) and the humidity to 55%. 
  • Put your hygrometer in a visible place to check on the variables. 
  • Leave the dehumidifier and heater running. Remember to close the door!
  • Bring in your honey supers and stack them. Put the first one on the base and then stack the next one on top of it, BUT first, rotate it so it doesn’t sit neatly as it normally would, but instead, they are crossed over each other. 
Diagram showing how to increase air flow through hive and reduce moisture content of honey
This is how the supers will look when they are cross-stacked. This will allow for better airflow without having to use a fan.
  • The air will flow underneath and in-between the supers allowing the honey to dry up.
  • Leave the supers in the room with the equipment running. Measure the moisture in the honey during the process using your refractometer. Make sure you take samples from different frames and supers to read more accurately. 
  • The time it will take the honey to dry out will depend on several factors, including how much moisture it had in the first place, how big the room is and how many supers you have in the room. 
  • Once you are happy with your readings (below 18.6% for Grade A honey), extract, bottle, and seal. 

Using a fan

For this, you will need a small fan that fits inside an empty super.

  • Repeat steps 1 and 2 from above
  • Stack the supers neatly like you normally would but make sure the last one is an empty super to support and keep the fan in place.
Diagram of beehive
Stack the supers on a base. Leave an empty super on top – this is where the fan will lie facing down so the air flows from the top to the bottom super.
  • Place the fan facing down on the empty super so the air will flow from top to bottom. 
  • Measure your honey’s moisture every day from different spots so you can tell when it’s ready. Adding the fan can reduce the time it takes as it promotes airflow. 
  • Finally, extract, bottle and seal!

Additional tips 

  • If you don’t have a fan that sits nicely on top of an empty super, just place a fan in the room and crisscross the supers like the first method. The fan will still promote airflow in the room, helping the process. 
  • Don’t turn off the dehumidifier (maybe just the heater if it becomes too uncomfortable for you to work) until you have bottled the honey, and always keep an eye on your hygrometer!
  • You might be tempted to leave the supers in the dry room until you get a very low moisture reading (less than 16%) but keep in mind that the less moisture honey has, the less runny it is – meaning it becomes harder to extract and work with. 

How To Reduce The Moisture Content In Honey After Extraction

Hopefully, the previous steps save you from reading this section because reducing the water content in extracted honey is significantly more difficult.

If you plan to sell your honey, your last resort will be to mix a high-moisture batch with the one you already know has a very low moisture level. This can be enough to bring down the overall water content and still meet the requirements to sell it. 

If that doesn’t work, however…

It’s best to be safe and keep this honey for personal use. The quicker you eat it, the better.

Storing honey at a temperature below 50 F (11 C) will also stop yeast activity, but the risk of fermentation returns once the temperature rises again. 

You can use this honey to prepare other foods that require further processing, like heated baked goods or sauces. 

If you are not planning on consuming it relatively quickly, keep an eye on the signs of fermentation which are:

  • A visible foam or froth on the top layer of the honey
  • It foams significantly while heated.
  • It smells a bit like sweet wine. 
  • The container in which it is stored builds up gas, so the lid looks bloated or protruding outwardly.
  • When you open the container, some gas is released.
  • The flavor is off or acidic. 

One or more of these signs might be present. So, if you see bubbles but taste ‘okay,’ it can still mean your honey is fermenting

Summing Up… What Is The Ideal Moisture Content Of Honey

  • The ideal moisture content of honey varies in different countries, but it is typically between 17-21%.
  • Bees reduce the moisture content of nectar to turn it into honey. They do this by mixing it with an enzyme called invertase, passing it mouth-to-mouth with other bees, and fanning their wings to evaporate the water.
  • Low moisture content is necessary to reduce the chances of fermented or spoiled honey.
  • The simplest way to ensure your honey has a low water level is to only harvest capped honey.
  • You can reduce the moisture content of honey before extraction through the use of airflow, as well as controlling the temperature and humidity in the room in which you perform the extraction.
  • Reducing the water content in honey after extraction is almost impossible unless you combine it with a batch of honey that has a low level of water.

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