Pollen Cleaning Machines

Pollen cleaning and sorting machines are sieves and airflow devices that separate bee parts, wings, wax crumbs, dust and broken pellets from dried bee pollen by making use of differences in size and weight. For small-scale production a hand-shaken sieve set and a simple fan are enough; in commercial production, vibrating sieves and machines with aspirators reduce the workload. Cleaning is done after the pollen has dried thoroughly.

Why is pollen cleaned?

It is not only pollen that falls into the trap drawer. Raw pollen may contain:

• bee parts such as legs, wings and hairs, and occasionally dead bees,
• wax crumbs and propolis particles,
• dust, sand and plant debris,
• pollen dust from broken pellets,
• insects and spoiled, mouldy pellets.

Cleaning is essential for the food safety, appearance and market value of pollen. However, cleaning does not rescue a spoiled product: mouldy or soured pollen cannot be put right by sieving and is thrown away entirely.

What principles is pollen cleaning based on?

Because pellets vary in size with the type of pollen, a single sieve is not enough. Usually two sieves are used together: the upper sieve holds back material larger than the pellets, and the lower sieve holds the pellets while letting dust and crumbs through.

What types of pollen cleaning machine are there?

Hand-operated sieve sets

Two- or three-tier nesting sieves made of stainless wire or food-grade plastic. They are the best starting point for hobby and small-scale production. Gentle shaking is enough; rough movement breaks the pellets.

Airflow cleaners

The pollen is poured slowly through an adjustable airflow. Heavy pellets fall, while wings, hairs and dust are blown away. The simplest form is pouring it from one container to another in front of an adjustable fan; machine-type devices have a feed hopper, an air duct and a dust collection chamber.

Vibrating and rotary sieves

Motorised sieves make the flow of pollen continuous and speed up work with commercial quantities. The vibration intensity should be adjustable; too much vibration breaks dry pellets.

Combined lines

In large operations sieving and aspiration are combined in a single machine; dust is collected in a cyclone or filter. Some facilities also use optical sorters adapted from the grain and seed sector. Investment at this level only makes sense for high-volume production.

When is pollen cleaned?

The main cleaning is done after drying. Moist pellets are soft; they are crushed in the sieve, clog it and stick together. From fresh pollen only large pieces (dead bees, leaves) are removed by hand. The same rule applies to pollen that is to be frozen fresh: before freezing only rough sorting is done, not fine cleaning.

After cleaning, dried pollen is kept in the freezer for a while; this is a common practice to neutralise the eggs of wax moth and other insects. It is then stored in airtight containers.

What should you look for when choosing a pollen cleaning machine?

• Capacity: The machine should be able to process the dried pollen from the busiest week in one working day; anything bigger is unnecessary investment.
• Interchangeable sieves: Sieves with interchangeable mesh sizes give flexibility for different pellet sizes.
• Adjustable airflow: Too strong an airflow also blows away small pellets; too weak an airflow cannot separate hairs.
• Food-contact surfaces: Must be stainless steel or food-grade plastic; painted, galvanised or rusting parts must not touch the pollen.
• Easy dismantling and cleaning: Pollen dust collects in corners, absorbs moisture and becomes a breeding ground for mould and wax moth. Parts that can be removed without tools are preferable.
• Dust collection: The separated dust should be collected in a bag or filter and not spread into the working area.

How do you clean pollen step by step?

1. Confirm with the finger test that the pollen is completely dry; the pellets should be hard and loose.
2. Clean the work area, sieves and containers; make sure they are dry.
3. Pass the pollen through the coarse sieve; dead bees, lumps of wax and large pieces stay on top.
4. Separate the dust and crumbs with the lower sieve; the pellets stay on the sieve.
5. Pass it through an airflow to blow away wings, hairs and light particles.
6. Finally look it over by hand on a light-coloured tray; remove any remaining foreign matter.
7. Give the clean pollen a batch number, keep it in the freezer for a while and put it into containers.

Maintenance, hygiene and common mistakes

At the end of every working day the sieves are brushed and the dust inside the machine removed. If wet cleaning has been done, all parts are used only once they are completely dry; dry pollen passing through a damp sieve picks up moisture. Separated dust and crumbs are not mixed back into the product.

• Sieving moist pollen: the pellets are crushed, the sieve clogs and the product sticks.
• Rough shaking or too much vibration: the proportion of broken pellets and dust increases.
• Strong airflow: small, light pellets are lost as well.
• Leaving the machine uncleaned: mould and wax moth develop in the accumulated dust and contaminate the next batch.
• Thinking that mouldy pollen can be rescued by cleaning: a mouldy batch is set aside entirely and thrown away.