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  1. A forager sips nectar from flowers
  2. She passes it to house bees
  3. Enzymes split the nectar sugars
  4. Droplets are stored in cells
  5. Water evaporates, honey ripens
  6. Cells are sealed with wax

At the flower

Honey begins at the flower. A forager – an older worker that now works outside the hive – sucks up nectar with her proboscis and stores it in her honey stomach, a widened part of the gut where nectar is carried rather than digested. The honey stomach holds at most about 70 milligrams of liquid, and real loads are smaller: the Canadian Honey Council bases its calculation on measured averages of between 25 and 40 milligrams per flight.

Bees fly further for nectar than one might expect. A classic 1982 study by Visscher and Seeley followed the dances of one colony in a deciduous forest in the north-eastern United States: half of the flights went to within 1.7 kilometres of the hive and 95% to within 6 kilometres. Distance changes with the season. In an English study that decoded more than five thousand dances, the average was about half a kilometre in spring and over two kilometres in summer, when fewer plants are in flower nearby.

Recent research shows that thickening starts on the way home. It was long assumed that nectar does not change in the honey stomach. In 2008, however, the South African researchers Sue Nicolson and Hannelie Human found that aloe nectar with about 20% sugar had reached 38–40% sugar in the honey stomachs of returning bees. A 2022 study in macadamia orchards showed that bees remove part of the water while still at the flower, and the only possible route is evaporation through the mouthparts.

In the hive

At the entrance the forager hands her load to house bees: she regurgitates a droplet of nectar and the receiver drinks it up. This mouth-to-mouth food exchange is called trophallaxis. Thermal-camera recordings showed that a contact of just one to two seconds can be enough to pass nectar on. Receivers also warm up and work faster when foragers bring nectar from a more rewarding source.

While processing nectar, bees add enzymes, mainly from their hypopharyngeal glands. Invertase splits sucrose, the main sugar in most nectars, into the simpler sugars glucose and fructose. Glucose oxidase turns some of the glucose into gluconic acid and hydrogen peroxide. The peroxide in turn is broken down by catalase, which reaches honey mainly from pollen.

Next, the water has to go. Nectar is far thinner than honey: according to Eva Crane’s overview it contains from under 20% to over 60% sugar, and the rest is mostly water. A bee pushes a droplet out onto her proboscis, holds it in the air for a moment and swallows it again – over and over. The droplets are then spread into cells, where they keep drying. Evaporation is helped by the air current that bees drive through the hive by fanning their wings. X-ray images of combs from a 2016 Swiss study revealed that bees often move the contents of cells elsewhere before storing them for good. Ripening takes from one to eleven days, depending on colony strength, humidity and the sugar content of the nectar.

Under the international Codex Alimentarius standard, ripe honey contains no more than 20% water (heather honey up to 23%), which keeps yeasts from fermenting it. Then comes the wax. It is secreted by wax glands on the underside of the workers’ abdomen; according to the Bee Research Institute at Dol in Czechia, they reach full activity from about the twelfth day of a bee’s life. Bees knead the wax scales into caps that seal the cells. The Swiss study found that the final stage of ripening is still going on after capping has begun – a race against the moisture that honey would otherwise draw back in from the air.

Honeydew, effort and harvest

Nectar is not the only raw material. Bees also gather honeydew – the sweet excretions of aphids, scale insects and other insects that suck sap from the phloem of plants and expel the surplus sugar. It becomes honeydew honey, often sold as forest honey. The Codex Alimentarius defines it as honey coming mainly from secretions of living parts of plants or from excretions of plant-sucking insects on living parts of plants.

The Canadian Honey Council estimates that to make one pound (454 g) of honey, bees visit about two million flowers and fly around 80,000 kilometres. This is a rounded calculation based on averages, and other estimates come out even higher. Much of that honey is eaten by the colony itself: for winter alone the University of Florida recommends about 40 kg of stores for colonies in cold climates. A beekeeper should take only the surplus.

For the harvest, the beekeeper takes frames whose combs are mostly capped. The caps are removed with a heated knife or an uncapping fork, and the frames go into an extractor. It spins them so that centrifugal force flings the honey out of the cells while the comb stays intact. The honey is then passed through sieves to remove bits of wax and left to settle in a tank. Foam and debris rise to the top and are skimmed off before the honey is put into jars.

Sources

  1. Canadian Honey Council: How to make a pound of honey
  2. Visscher, P. K., Seeley, T. D. (1982): Foraging strategy of honeybee colonies in a temperate deciduous forest. Ecology 63(6)
  3. Couvillon, M. J., Schürch, R., Ratnieks, F. L. W. (2014): Waggle dance distances as integrative indicators of seasonal foraging challenges. PLoS ONE 9(4)
  4. Nicolson, S. W., Human, H. (2008): Bees get a head start on honey production. Biology Letters 4(3)
  5. Nicolson, S. W., Human, H., Pirk, C. W. W. (2022): Honey bees save energy in honey processing by dehydrating nectar before returning to the nest. Scientific Reports 12
  6. Farina, W. M., Wainselboim, A. J. (2001): Thermographic recordings show that honeybees may receive nectar from foragers even during short trophallactic contacts. Insectes Sociaux 48(4)
  7. Eyer, M., Neumann, P., Dietemann, V. (2016): A look into the cell: honey storage in honey bees, Apis mellifera. PLoS ONE 11(8)
  8. Agroscope / Univerzita v Bernu (2016): Secrets of honey-making by bees unveiled – tisková zpráva
  9. Přehledový článek o enzymech v medu a jejich reakcích (PubMed Central, 2022)
  10. Eva Crane Trust: nektar a klasifikace koncentrace cukru v nektaru
  11. Codex Alimentarius: Revised Codex Standard for Honey (Codex Stan 12-1981, rev. 2001)
  12. Výzkumný ústav včelařský Dol (2018): Vosk nad zlato – certifikovaná metodika
  13. University of Florida IFAS Extension: IN1006 (zimní zásoby včelstva)
  14. University of Florida IFAS Extension (2022): Honey Harvesting: Preparation
  15. KALRO: Sub-Module 7 – Honey harvesting and processing