What Is Propolis and How UK Beekeepers Use It
Walk into any active beehive in Britain and you will notice something immediately: a sticky, resinous substance coating the interior surfaces, sealing gaps, varnishing the frames, and occasionally cementing the crown board so firmly to the brood box that you need a hive tool to prize it free. That substance is propolis, and it is one of the most remarkable materials produced by the honeybee. For UK beekeepers, propolis is simultaneously a practical nuisance and a genuinely useful product with a well-documented history of applications in health, industry, and traditional medicine.
This article covers what propolis actually is, how honeybees make it, why it matters inside the hive, and how British beekeepers are harvesting and using it today. We will also look at the commercial market, the science behind its properties, and practical guidance for anyone keeping bees in the UK who wants to work with propolis rather than simply scraping it off their equipment.
What Is Propolis?
Propolis is a composite resinous mixture that honeybees (Apis mellifera) collect from plant sources and then process with their own salivary secretions and beeswax. The word itself derives from the Greek: pro meaning “before” or “in defence of” and polis meaning “city.” It is, in effect, the defensive cement of the bee city.
The chemical composition of propolis is complex and varies considerably depending on the plant sources available in a given geographic region. Broadly speaking, propolis contains:
- Resins and balsams: approximately 45–55% of the total composition
- Waxes: 25–35%
- Essential oils and volatile compounds: 10%
- Pollen: 5%
- Other organic compounds including flavonoids, phenolic acids, and minerals: the remainder
In temperate climates like Britain’s, bees collect the majority of their resinous raw material from the buds and bark of trees. The most important sources in the UK are poplar species (Populus spp.), horse chestnut (Aesculus hippocastanum), birch (Betula spp.), alder (Alnus glutinosa), and various willows (Salix spp.). The resin from poplar buds in particular is known to be rich in flavonoids, giving British and Northern European propolis a chemical profile distinct from tropical varieties, which may draw on additional plant families.
The colour of propolis ranges from pale yellow-green when freshly worked to deep red, brown, or almost black as it ages and oxidises. In summer it remains somewhat pliable; in winter and in cold conditions it becomes brittle, which is why experienced beekeepers learn to handle hive components more carefully during cold inspections to avoid cracking propolis deposits unnecessarily.
How Do Bees Collect and Process Propolis?
Forager bees collect resin using their mandibles, scraping it from plant surfaces and packing it into their pollen baskets (corbiculae) on their hind legs. Unlike pollen or nectar, propolis collection is a slow and physically demanding task. A single bee may spend up to an hour loading her corbiculae with resin before returning to the hive. Once back, she cannot offload the material herself, as propolis sticks firmly and does not flow like nectar. Instead, other bees must assist in pulling and cutting the resin free.
Not all colonies collect propolis with equal enthusiasm. Research has shown that propolis-collecting behaviour has a genetic component, and some strains of honeybee are notably more productive than others. Certain populations of Apis mellifera from warmer climates, such as the Italian bee, tend to use less propolis. The native British black bee (Apis mellifera mellifera), and strains closely related to it, are typically heavier propolis users — a trait that makes excellent ecological sense in the damper, cooler conditions of northern Britain where antimicrobial defence is particularly valuable.
The British Isles have seen considerable advocacy for the native black bee in recent decades. Organisations such as the Native Honey Bee Society and regional groups including the Colonsay Bee Improvement Project in Scotland have worked to conserve and study A. m. mellifera, noting that its propolis production is among its defining characteristics.
Why Do Bees Use Propolis?
Structural Sealing and Temperature Regulation
Bees use propolis to seal any gap in the hive smaller than the “bee space” — the critical measurement of 6–9 mm first systematised by American beekeeper Lorenzo Langstroth in the nineteenth century. Gaps larger than bee space will be left open as thoroughfares; gaps smaller than bee space get propolised shut. This means cracks in woodware, rough surfaces inside supers, and the junction between hive components all receive a propolis treatment over the course of a season.
This sealing activity helps regulate the hive’s internal microclimate, reducing draughts and maintaining the stable temperature and humidity that the colony requires to rear brood successfully. In the notoriously wet and windy conditions common across much of the UK — from the Western Isles to the West Country — this protective function is particularly significant.
Antimicrobial Defence
Perhaps the most important function of propolis is its role as an antimicrobial barrier. The flavonoids and phenolic compounds it contains have been shown in numerous studies to exhibit antibacterial, antifungal, antiviral, and antiparasitic properties. Inside the hive, propolis creates what researchers have described as a “social immune system” — an environmental defence that supplements the individual immune responses of each bee.
Studies published in journals including Behavioural Ecology and PLOS ONE have demonstrated that colonies housed in environments lined with propolis show lower pathogen loads, more robust immune gene expression, and in some experiments, greater resistance to American foulbrood (Paenibacillus larvae), one of the most destructive diseases a British beekeeper can face. American foulbrood is a notifiable disease in England and Wales under the Bee Diseases and Pests Control (England) Order 2006, and its presence must be reported to the National Bee Unit.
Mummification of Intruders
When an intruder too large to be removed enters the hive — a mouse that crawled in during autumn, for example, or a large slug — bees will kill it and then coat it entirely in propolis. This mummification prevents decomposition and the associated risk of bacterial contamination within the hive. It is a behaviour that strikes many new beekeepers as both remarkable and slightly unsettling when they first encounter a perfectly preserved, varnished mouse inside an overwintered hive.
Entrance Restriction
In autumn, bees frequently use propolis to reduce the size of the hive entrance, adding to what the beekeeper may already have done with an entrance block. This restricts cold air flow and makes the entrance easier to defend against robbing bees and wasps — a significant problem in British hives from late summer through to October, when wasp colonies are at their largest and natural forage is diminishing.
Propolis and the Main UK Hive Types
The National Hive
The British Standard National hive is the most widely used hive design in England, Wales, and Scotland. Its brood box and super dimensions are well suited to British bee management practices, and beekeepers using National equipment will be very familiar with propolis as a feature of regular inspections. The joints between boxes, the runners on which frames hang, and the rebated edges of the crown board all accumulate propolis steadily through the active season.
Because National frames hang from lugs resting on runners, these contact points are particularly prone to propolising — sometimes to the extent that frames become genuinely difficult to remove without damaging comb. A good hive tool, kept clean and warm, is an essential piece of kit. The British Beekeepers Association (BBKA) recommends carrying a hive tool at all times during inspections and cleaning it regularly to avoid transferring pathogens between colonies.
The WBC Hive
The WBC hive — designed by William Broughton Carr and perhaps the most recognisable hive silhouette in Britain — presents additional propolis challenges. Its double-walled construction means more surfaces and joints, and the lifts (the outer casing sections) can become firmly bonded to the inner boxes if propolis is allowed to accumulate unchecked. However, the WBC’s popularity in domestic UK gardens is undimmed, and many hobby beekeepers consider the management of propolis within its structure simply part of the rhythm of keeping bees.
The Langstroth Hive
Langstroth hives are used by some UK beekeepers, particularly those with connections to commercial beekeeping or who have trained in countries where Langstroth is standard. The larger brood volume can suit productive strains well, but the same propolis management considerations apply. Commercial UK apiaries operating Langstroth equipment at scale often use propolis traps systematically, treating propolis as a marketable crop rather than a nuisance.
Top Bar and Warré Hives
Both top bar hives and Warré hives have gained followings among UK natural beekeeping enthusiasts, often associated with organisations such as the Natural Beekeeping Trust based in Gloucestershire. In these hive types, bees are given considerably more latitude to build comb and use propolis according to their own inclinations. Propolis deposits are generally left in place rather than scraped away, and some practitioners argue that the resulting propolised interior creates a healthier environment for the colony — a position that has some support in the scientific literature, though it remains a topic of active discussion within the UK beekeeping community.
Harvesting Propolis in the UK
Propolis Traps
The most efficient method of collecting propolis from a beehive is the propolis trap — a sheet of flexible plastic or similar material perforated with narrow slots (typically 1–2 mm wide) placed beneath the crown board. Bees, encountering these gaps, will fill them with propolis. Once the trap is well loaded — a process that may take a full season in a moderately propolis-productive colony — it is removed, placed in a freezer bag, and frozen. When frozen, propolis becomes brittle and can be cracked free from the trap simply by flexing it, after which the propolis fragments can be collected.
Moving Forward
Once you have the fundamentals in place, the possibilities open up considerably. The UK offers fantastic opportunities for anyone interested in this hobby, and with the right foundation you will be well placed to make the most of them.