Propolis is obtained in two ways, and the difference entirely determines the value of the product.

From a screen

A plastic mat with fine openings is placed on top of the frames. The bees fill the openings because they perceive them as a gap.

Propolis obtained this way is clean: no wood, no paint, no dirt. Only this is usable as a product.

Scraped from the hive

At every inspection propolis comes off rebates, frame lugs and covers. This is mixed with wood splinters, paint and dirt.

It cannot be sold as a product, but it need not be discarded either — for personal use or for extraction with filtration it is usable.

Harvesting the screen

The screen is chilled until the propolis becomes brittle, then flexed; the propolis breaks off.

At room temperature propolis is sticky and unworkable. Cold is not a refinement here but a necessity.

When

Mainly in late summer and autumn, when the bees turn to sealing the hive. The screen stays in for weeks; propolis is not collected in one go.

Some draught encourages filling — the bees seal what feels to them like a leak.

What it costs the colony

Less than most other products. Even so, the colony spends labour on filling, and that labour does not go into foraging.

Source and composition

Propolis is collected plant resin. Its composition therefore differs considerably by region, depending on which trees and shrubs are available.

This also means research on one propolis does not automatically apply to another.

Rules

Do not harvest during a treatment period; propolis takes up fat-soluble substances. Allergic reactions are possible and should be stated.