To understand the moisture or water content in honey, we should understand the process of honey-making by honey bees.
Honeybees collect nectar from flowers to make honey. Nectar has around 70% water.
A honeybee collects nectar and process it through regurgitation and deposited into hexagonal honeycomb cell.
Honeybees then dry out the excess moisture through fanning by wings.
Once the collected nectar (honey) attains a moisture level of 18%, honeybees seal the comb cell with wax. This is mature honey or ripe honey.
During commercial extraction of honey, beekeepers often extract honey before ripening. This unripe honey has moisture levels anywhere between 20-25%.
Unripe honey tends to ferment because of its high moisture content. Hence has a lesser shelf life.
There are various tests to check the unripe honey.
Thumb test: Put a drop of honey on the thumb. If it slips from the nail, it is unripe honey. If it stays it is ripe honey.
Dissolution test: Pour a spoonful of honey into a glass of water. If it dissolves easily it is unripe honey. If it stays longer before dissolves, it is ripe honey.
Sticky fingers test: Take a drop of honey between thumb and index finger. Rub it to observe its stickiness. ripe honey is more sticky. Unripe honey is less sticky.
Refractometer or Brix meter :
The moisture content of honey can easily be identified using equipment like a refractometer. It can give us exact reading in percentage.
According to the parameters, honey should have moisture levels in a range between 18-20%.
The conventional methods mentioned here are mistakenly considered as purity tests, which is not true.