Glossary
The distinction between honeycomb cells that bees have sealed with a wax cap (indicating ripened honey at or below 18.6% moisture) and open cells still being dehydrated. The capping status is a beekeeper's primary field indicator of honey readiness for harvest. Harvesting uncapped honey risks fermentation.
When forager bees return to the hive with nectar (70 to 80% water), they deposit it in cells where house bees begin the ripening process: they fan the nectar with their wings, creating air flow that evaporates the excess water. They also add the enzyme invertase, which converts sucrose into glucose and fructose. When the moisture content drops to approximately 17 to 18%, the bees consider the honey ripe and seal the cell with a thin cap of freshly secreted beeswax. This cap is the colony's quality certification: the honey inside is properly ripened and preserved.
Beekeepers use a simple guideline for harvest readiness: when at least 80% of the cells on a frame are capped, the honey is ready to extract. The remaining 20% of uncapped cells likely contain honey that is very close to ripe (the bees may cap those cells within days). Extracting a frame that is less than 80% capped risks mixing adequately ripened honey with high-moisture nectar, raising the overall moisture content above the safe threshold.
Honey extracted above 20% moisture is at high risk of fermentation. Osmophilic yeasts (which can survive in honey's concentrated sugar environment) begin multiplying, converting sugars to alcohol and carbon dioxide. The honey develops an off-taste, fizzy bubbles, and eventually spoils. Properly capped honey, extracted at 17 to 18% moisture, has an indefinite shelf life because the water activity is too low for yeast to reproduce.
The shake test: Hold a frame of honey horizontally and give it a firm downward shake. If nectar sprays out of uncapped cells, the honey is too wet. If nothing comes out despite shaking, the uncapped cells likely contain adequately ripened honey. This is a rough field test; a refractometer provides the precise measurement.
Mildly fermented honey (slightly fizzy, yeasty aroma) can be used in baking (the off-flavors are masked) or intentionally continued into mead production. Heavily fermented honey with strong alcohol or vinegar flavors is best discarded or used as a fermentation starter. Prevent the problem by never extracting frames that are less than 80% capped.
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