Propolis: origin, function in the hive and harvesting
Propolis is a resinous substance that bees collect in nature. They gather it, process it and distribute it inside the hive, where it performs specific functions in colony life. For beekeepers, it is one of the most fascinating hive products.
Botanical origin
Bees collect propolis from the buds and bark of various trees and shrubs: poplars, birches, chestnuts, conifers and many others. The substance collected is a resin produced by the plant as natural protection against external agents.
Collection takes place mainly on warm days, when temperatures exceed 20°C and the resin is more malleable. Forager bees dedicated to propolis collection carry the material on their hind legs, as they do with pollen.
Processing and use in the hive
Once in the hive, propolis is processed by the bees: it is briefly chewed and mixed with wax and other secretions until it reaches a workable consistency. Bees use it to:
- coat the inner walls of the hive;
- seal unwanted cracks and openings;
- reduce the size of the entrance in winter;
- cover foreign objects they cannot physically remove.
Propolis contributes to the hygiene of the colony. Bees tend to seal openings narrower than about 4.5 mm; larger ones are closed with wax instead.
How beekeepers harvest it
Traditionally, propolis was collected by scraping the inside of the hive, the frames and other movable parts. This method was laborious and produced material often mixed with impurities.
Over time, propolis traps became widespread: grids with calibrated-width slots placed inside the hive. Bees fill them with propolis in an attempt to seal the openings. The grid is then placed in the freezer — cold makes propolis brittle — and the propolis detaches easily. This method can significantly increase the amount collected and generally produces purer material.
Composition and variability
Propolis composition varies considerably depending on local flora and season. In general terms it contains resins, waxes, essential oils, pollen and various organic compounds. The colour can range from yellow-green to dark brown, red or near-black. The flavour is typically resinous and astringent.
This variability makes propolis a difficult product to standardise: each batch reflects the plants present in the hive's territory at that time.
Storage
Raw propolis keeps well in a cool, dry place away from light. At room temperature it can become very sticky; cold makes it more compact and easier to handle. It can be stored for extended periods as long as it is kept away from moisture.
A brief history of research
Scientific interest in propolis grew significantly from the 1960s onwards. Danish biologist Karl Lund Aagaard was among the first to promote systematic data collection on propolis, stimulating research that helped bring this substance to wider attention beyond the beekeeping world. Since then, propolis has become the subject of numerous scientific studies published in peer-reviewed journals, analysing its chemical composition and biological characteristics.
Propolis is one of the elements that make the hive a complex and fascinating biological system. Each hive produces propolis with different characteristics, linked to the territory and the season. Explore the Florabella apiary diary →
Sources
Bankova V. et al., Propolis: a review of its pharmacological properties and geographical variation, Journal of Ethnopharmacology, 2000. DOI: 10.1016/S0378-8741(99)00176-1 · Kocot J. et al., Antioxidant Potential of Propolis, Bee Pollen, and Royal Jelly, Oxidative Medicine and Cellular Longevity, 2018. DOI: 10.1155/2018/2437273
