How To Measure Moisture Content When Harvesting Honey

Learn all about how to use a refractometer to increase your honey production. Measuring moisture content can help your hives thrive.

Reader Contribution by David Burns
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Learn all about how to use a refractometer to increase your honey production. Measuring moisture content can help your hives thrive.

Let’s examine the importance of using a refractometer! A refractometer is used to measure the moisture level in honey. Beekeepers need to become more aware of what the moisture content is in the honey they are harvesting. Harvest it too soon, and the excess moisture content will cause the honey to go bad or ferment, and when it does, you’ll be seeing customers bringing your honey back wanting a refund and spreading around bad news about your honey to others. You don’t want that.

So let’s look at:
1) How using a refractometer can increase your honey production
2) How a refractometer works
3) How to use a refractometer

Refractometers and Honey Production

First, how can a refractometer increase your honey yields? Typically, you should not harvest honey from the hive until all the frames are capped over, meaning all of the cells in the honey frames are sealed with the bee’s wax cappings. But, often the bees fill up the honey cells and do not seal them over. This means that the bees cannot store any additional nectar because there is no room. This is especially the case in certain types of climates where the bees may never completely seal the honey comb.

Meanwhile, you could have been giving them more frames to fill. What you can do is remove the frames that may still not be completely sealed and give them an empty frame to continue to store incoming nectar. Then, place your filled but unsealed frames in a room with a dehumidifier and a fan, and use your refractometer to measure and dry the honey to around 17% to 18% moisture. By removing your frames earlier than normal and drying them, you can place empty frames in the hive to be filled. This is how a refractometer can help increase your honey yields.

Secondly, just how does a refractometer work? Prisms bend light. A refractometer operates in much the same way, but the light will react differently depending on the amount of sugar as the light passes through the honey (sugar), the daylight plate, and the main prism assembly. This reflective light lands on a scale, which can then measure the moisture in honey.

How to Use a Refractometer

First, open the light plate and expose the light blue area. Now, take a couple drops of honey so the honey will cover the blue area completely. If you use too much honey, it will just be messy. You just need enough to cover the blue plate.

Next, close the light gate firmly to spread the honey evenly over the blue plate.  Then, simply look into the view finder and take your reading.

To clean your refractometer after use, use a damp cloth and remove the honey from all areas. 

How To Invest In The Right Model

While refractometers are very easy to use, I would strongly urge all beekeepers not to purchase the inexpensive refractometers for under $100. These might be accurate, but many beekeepers have found they are plagued with problems. In my opinion, save up your money and invest in a solid model, such as one I use made by Atago, a superior and well-established refractometer company that sells models designed especially for honey. My Atago model operates perfectly every time, and it’s durable, handheld, and affordable. The cost is around $270.

Even though there is an initial investment, you benefit from increased honey yields and the prevention of fermenting honey.


Find David Burns online at Long Lane Honey Bee Farms.