How bees collect and process nectar

In the field

A forager draws nectar through her proboscis into the honey stomach, a crop holding around 40 milligrams — roughly half her own body weight when full. She may visit between fifty and over a thousand flowers to fill it, depending on how generous they are.

Enzymes are already being added at this point. Invertase from her glands begins splitting sucrose into glucose and fructose, and glucose oxidase is introduced, which will later generate the hydrogen peroxide that helps keep honey stable.

The handover

1. 1Return and transferThe forager passes her load to a receiver bee mouth to mouth. She does not deposit it in a cell herself.
2. 2ManipulationThe receiver repeatedly extends a droplet of nectar between her mouthparts and draws it back in, exposing a large surface to the hive air. This is where most water loss begins.
3. 3DepositThe partly ripened nectar is spread in a thin film across the walls of open cells, maximising evaporation area.
4. 4FanningWorkers fan at the entrance and inside, driving a current of air through the nest and carrying the moisture out.
5. 5CappingWhen moisture falls to around 17-18%, the cell is sealed with a wax capping. A capped cell is the colony's signal that the honey is finished.

What has changed chemically

The transformation is genuine chemistry, not merely drying. Sucrose is inverted into its component sugars, acids are produced, and enzymes are added. A dehydrated nectar would not be honey.

The scale of the work

Producing 500 grams of honey requires the nectar of something in the region of two million flower visits and a total distance flown that is frequently quoted as equivalent to twice around the earth. Those figures are estimates and the orders of magnitude are right.