Water Content Calculator
Enter your refractometer reading and instantly find out whether your honey is ready to extract.
The water content determines the quality and shelf life of your honey. Below 18 % it is safe from fermentation, from 20 % it is no longer marketable. Read more in the article Measuring the water content in honey.
Assessment
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Refractometers are calibrated for 20 °C. If the sample differs, 0.08 % is applied per degree – subtracted above, added below. Instruments with automatic temperature compensation (ATC) do not need this; enter 20 there.
Record harvests per colony and type
Note the water content of every harvest and after two seasons you can see which sites deliver dry honey.
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Frequently Asked Questions
My refractometer reads 81.5 – is my honey too moist?
No, quite the opposite. 81.5 is a value on the Brix scale and corresponds to about 17.5 % water, not the water content. Many honey refractometers carry both scales side by side, and reading the wrong one leads people to discard perfectly good honey. Switch the calculator above to °Brix and it will convert.
How accurate is the conversion from Brix?
It is an approximation. For honey, Brix and water content stand in no fixed relationship – it depends on the type of instrument. The calculator uses (100 − Brix) − 1.0, which matches the Chataway table to within about two tenths of a per cent. If your device has a water content scale, read that instead; it is more accurate.
How do I measure correctly?
Calibrate the instrument before the season and measure from several combs – the content varies within a colony. The most telling sample comes from sealed cells in the centre of the comb.
At what water content may honey no longer be sold?
Above 20 % it may no longer be sold as honey; it can still be passed on as baker's honey. Heather honey from Calluna is an exception up to 23 %. The German D.I.B. jar is stricter and requires below 18 %.
Why does temperature matter?
Refractometers are calibrated for 20 °C. Per degree of deviation the reading is off by roughly 0.08 %: above 20 °C the instrument shows too little water, below it too much. At 15 °C and a reading of 18.5 % the true value is around 18.9 %. Instruments with automatic temperature compensation do this themselves.