How Beekeepers Check Honey Moisture Before Extraction (and Why It Matters)

Every jar of honey starts as nectar, and nectar is mostly water. Before a beekeeper takes a single frame off the hive, one question decides whether the honey will stay delicious on your shelf or start to ferment: is it dry enough yet? Here's how beekeepers check the moisture in honey before extraction, the numbers they aim for, and the simple tools they use, from a quick look at the wax cappings to a pocket refractometer.

Why the water content of honey matters

When bees bring nectar back to the hive, it can be up to about 80% water. Inside the hive, worker bees spread it through the cells and fan their wings to evaporate the extra water, while the enzymes they add transform the sugars. When the honey is ripe, usually at about 17 to 18% water, they seal each cell with a thin cap of fresh beeswax.

Getting that number right is what keeps honey stable. All raw honey naturally contains a few sugar-tolerant yeasts (called osmophilic yeasts). In ripe honey they can't grow, because there's too little free water. Give them more water and they wake up, feed on the sugars, and the honey ferments: it foams, smells sour or yeasty and tastes off. The research honey scientists rely on gives a clear picture:

• Under about 17% water: honey is very stable and isn't expected to ferment within a year, whatever its yeast count.
• About 17 to 19%: the risk rises, especially if the honey holds more yeast or is stored somewhere warm.
• Above about 19%: fermentation is likely within the year after harvest.

Water content also changes how honey behaves in the jar. Wetter honey is thinner and runnier, drier honey is thicker, and water even plays a part in how quickly honey crystallizes. We explain that side of the story in Why Natural Honey Crystallizes and What to Do When It Happens.

The numbers in Canada

In Canada, moisture is part of how honey is graded. Under the Canadian Food Inspection Agency's grade standards for honey, Canada No. 1 honey can contain no more than 17.8% moisture, Canada No. 2 no more than 18.6%, and Canada No. 3 no more than 20%. Slightly higher limits apply to honey labelled pasteurized. In practice, most beekeepers aim for about 17 to 18% water, which keeps raw honey in the top grade and protects it from fermenting.

Check 1: Look at the cappings

The first check happens at the hive. Bees only cap honey once they've dried it, so the wax cappings are the bees' own sign that the honey is ready. A frame that is fully capped, or close to it, is usually ready to harvest. A common rule of thumb among beekeepers is to extract only frames that are at least 75 to 80% capped.

Frames with a wide band of open, glistening cells are the ones to watch. That honey may still be thin, unripe nectar, so the frame stays in the hive a little longer, or goes on to the next checks.

Check 2: The shake test

For a frame with some open cells, many beekeepers use a quick field test. Holding the frame flat, with the open cells facing down over the hive or a clean surface, they give it one firm downward shake. If drops of liquid rain out, the honey in those cells is still too wet, and the frame goes back into the hive so the bees can finish their work. If nothing falls out, the honey is thick enough to stay put, which is a good sign. The shake test is only a rough guide, though, so beekeepers who sell their honey confirm it with a measurement.

Check 3: Measuring moisture with a refractometer

A honey refractometer is the most precise everyday tool for the job. It's a small handheld instrument that measures how much a thin layer of honey bends light. The more sugar and the less water, the more the light bends, and the scale turns that into a moisture percentage. A single drop of honey is enough.

Here's how beekeepers typically use one:

1. Calibrate it with the calibration fluid or block that came with it, so the readings are accurate.
2. Sample from several places. Moisture can vary from cell to cell and frame to frame, so beekeepers take a few drops from different cells, especially the uncapped ones, and blend them on the prism. After extraction, they stir the honey well before sampling.
3. Read it at the right temperature. Refractometers are calibrated for about 20 °C. Many correct for temperature automatically, but very warm or very cold honey can still throw a reading off.
4. Decide. If the reading is in the target range, the frames are ready. If it's too high, the honey isn't ready yet.

A refractometer also answers questions the cappings can't. Late in the season, when the nectar flow suddenly stops, bees sometimes leave perfectly ripe honey uncapped. And after long stretches of humid weather, honey under wax cappings can occasionally test wetter than expected. A reading takes the guesswork out of both.

Humidity: the beekeeper's invisible enemy

Honey is hygroscopic: it pulls water out of the air. So the job isn't finished once the frames come off the hive. Boxes of honey left in a damp shed, or open pails in a humid extraction room, can absorb moisture and creep back above the safe range.

Quebec summers can be hot and humid, so beekeepers here pay close attention to the air in the honey house:

• Frames are extracted soon after they come off the hive, instead of waiting for days.
• Many beekeepers run a dehumidifier in the extraction room, often with fans moving air around the stacked boxes. Some use a warm, dry room to gently bring slightly wet frames down to the target before extracting, checking progress with the refractometer.
• Extracted honey goes into sealed food-grade pails or stainless steel tanks with tight lids, so it can't take on water while it waits to be jarred.

One more check before jarring

Careful beekeepers test again after extraction and straining, because the honey from many frames is now blended together. If honey has been stored in bulk for weeks or months, it gets another quick reading before it goes into jars. It's a small step that protects every jar on the shelf.

What if the honey is too wet?

When honey reads too high, beekeepers have a few options. Frames still on the hive can simply stay there longer while the bees finish drying them. Frames already pulled can be dried in a warm, dehumidified room before extraction. Honey that can't be brought down to a safe level isn't jarred for sale. What a good beekeeper won't do is jar wet honey and hope for the best.

How to keep your honey at its best at home

• Close the lid tightly after every use: honey absorbs moisture from the air in your kitchen too.
• Always use a clean, dry spoon. A few drops of water, added again and again, can raise the moisture where they land.
• Store it at room temperature, away from the kettle, the dishwasher and the stove.
• If a jar ever foams, bubbles or smells sour like beer or yeast, it has likely started to ferment.

Frequently asked questions

What is the ideal moisture content of honey?

Most beekeepers aim for about 17 to 18%. Below about 17%, honey is very unlikely to ferment. In Canada, top grade honey (Canada No. 1) can contain no more than 17.8% moisture.

Is capped honey always ready to extract?

Usually, yes. Bees cap honey once they've dried it. Capping isn't a perfect guarantee, though, especially after long spells of humid weather, which is why many beekeepers confirm with a refractometer.

Can you harvest honey that isn't capped?

Only if it tests dry enough. Uncapped honey can be ripe, for example at the end of a nectar flow, but the only reliable way to know is to measure it.

Why does honey ferment?

Natural sugar-tolerant yeasts in honey start to grow when there's too much water. That happens when honey is harvested before it's ripe, or when it absorbs moisture from the air afterwards.

Does crystallized honey have too much water?

No. Crystallization is natural and depends mostly on the honey's sugars and on temperature. Crystallized honey is still perfectly good honey.

Taste ripe, raw Quebec honey

We extract and jar our honey ourselves, from our hives around Montreal. Discover our raw Quebec honey, starting with our Wildflower Honey and our Whipped Honey. Curious how beekeeper honey differs from supermarket honey? Read Why Buy Honey from a Beekeeper Instead of the Grocery Store? Have a question about your honey? Write to us at info@mielbrut.com or on Instagram (@mielbrut_com).

Header photo: Cristina Marin / Unsplash