Centrifugal honey extraction in frameless-hive beekeeping

by Rainer Krell

An adaptation to modern centrifugal honey extraction can allow traditional, irregular honeycomb to be spun quickly and efficiently, increasing both the yield and the quality of the honey.

Beekeepers have made great strides in designing equipment that allows greater manipulation of colony conditions, and increases yields and quality of the extracted honey itself. The beekeeping methods used in industrialised countries, which use standardized boxes with movable wooden frames within which bees build their wax combs, have been developed over the last 150 years.

Traditional beekeeping

The straw skeps of northern Europe, the clay pots and cylinders of northern Africa, and the bark and log hives, also of Africa, are examples of traditional ‘frameless’ beekeeping. But honeybees’ behaviour varies with different climates and different environments. Economic, cultural and social conditions, too, differ widely throughout the distribution area of the honeybee. Movable-frame hives have always been expensive and difficult to make, and despite the advantages of easier handling, have not always been the most productive or economic choice. Intermediate hive-types then evolved, hives that combine many of the advantages of both traditional and modern beekeeping. Cheaper, locally available building materials can be chosen and less precision is necessary in their construction. The bees are encouraged to build their combs on wooden sticks or bars laid across the top of the hive container. The result is referred to as a top-bar hive, and it still permits the easy moving of brood or honeycombs for hive management and honey harvesting.

But since bees store honey in tiny hexagonal wax cells, the harvesting of honey is not finished when the combs are removed from the hive: the honey still has to be separated from the wax. In ancient times and still today honey is eaten with the comb, sometimes with the brood and pollen.

Extracting the honey

Honey in a jar has been carefully removed from the wax combs. In modern beekeeping the wax caps with which bees seal their honey cells are removed by the beekeeper with a knife, the wooden frame with uncapped honey comb is placed in a centrifuge and the honey is spun out of the cells. The wax caps, referred to as cappings, are then processed.

In traditional beekeeping, which does not use frames and centrifuges, honey can only be allowed to drip from broken-up combs or be squeezed out by hand. Appropriate technology has provided special presses to squeeze the broken-up comb more efficiently. This process is slow: presses are still expensive and cannot be used for frame hive beekeeping and the honey almost always contains a lot of pollen. What is really needed is a modern centrifugal extractor that can be used with traditional non-frame beekeeping.

Centrifugal extractors

High-technology beekeeping has solved this problem inadvertently, by adapting radial centrifugal extractors to process cappings, which resemble in many ways the irregular and broken combs harvested from frameless hives. A commercial beekeeper in the US used the same 72-frame radial extractor to spin both frames and cappings. Stainless steel quarter sections were laid on the bottom struts of the cage, and vertical sheets, perforated by ¼ -⅜ inch holes, two per square inch, were fitted to the vertical reinforcements. In less than 30 minutes over 30 gallons (140 litres) of cappings were spun relatively dry with no reduction in honey quality.

In 1987, I went to Zambia and Malawi for Africare to help beekeeping extension officers. Local beekeepers did not have or want 72- frame radial extractors, but after their harvest from bark hives, Kenya top-bar hives and modified Dadant top-bar hives, they were left with a honey and broken comb mixture very similar to the cappings from frame-hive beekeeping.

The most common practice among advanced frameless-hive beekeepers is to press honey from the comb mixture. Sometimes honey is left to drip from the broken combs through a screen just as some frame hive beekeepers let honey drip from cappings. For the project in Zambia four-frame extractors had been purchased, which were used only for the processing of frames. The bulk of the comb and honey mix from bark hives or incomplete frames was still processed by pressing.

Modifying small extractors

The four-frame extractors available had a basket to hold the frames, made out of twomesh (three wires or two holes per inch) wire screen or hardware cloth. The bottom of the basket was a solid sheet of stainless steel. This was fortunate since it saved a lot of work and material when converting to centrifuging the honey and comb mixture. All that was necessary was to lay a finer mesh hardware cloth (eight-mesh) around the bottom five to ten inches of the basket, pour in about three gallons (14 litres) of the well broken-up mixture of comb and honey, and spin it.

In less than five minutes most of the honey was spun out. Pressing the same quantity through a coarse cloth removed only two or three percent more honey. The quantity of residual honey was slightly higher when larger quantities were spun at one time.

The faster speed is impressive when compared to the 15 or 30 minutes (depending on the cloth mesh size) it takes to press even a small quantity of honey. A larger mesh used in the extractor will speed up the process, but more and larger wax particles will end up in the extracted honey. This may be perfectly tolerable depending on the processing or filtering methods to be used for the final cleaning of the honey. A finer mesh, like fly or mosquito screen, will leave very little wax in the honey, but prolongs the extraction. The eight-mesh hardware cloth was found to be quite satisfactory. Any wax particles passing through the cloth were allowed to float to the surface of the settling honey and were removed easily with a damp cloth laid across the surface of the flotsam. This size screen did not have to be removed for cleaning as frequently as the finer mesh.

Often the finer mesh sizes are not available locally, but the two-mesh or five-mesh hardware cloths usually are. (The latter is also called coffee wire in some places.) Two or more layers of these screens can be wired together, with each wire cross centred over the hole of the other layer, in order to achieve a finer mesh size. If the screen inserts are made of two or three separate pieces they are easier to insert into the basket, but one piece of flexible plastic mosquito screen or similar material may be used as well. An inch or two of this soft screen should rest horizontally on the bottom plate. Many extractors do not have a bottom plate and one may have to be made: wood or galvanised metal sheets will work.

If absolutely no screen material can be found, Stainless or galvanised steel or aluminium sheets can be substituted. Once cut to size they can be perforated with various size holes, up to *s inch, either by drilling or with a hammer and nail. Various thicknesses of plastic pieces from buckets or bowls can be used as well.

If you have a reversible frame extractor with individual cages holding each frame, the cages can either be lined with a sack of plastic mosquito screen or they can be removed completely and replaced with a strong wire cage modified as described above. The sacks can be cleaned and filled by one person while someone else spins another set of sacks. Several of these sacks could be laid on top of each other or hung from the inside top of the cage to increase the processing capacity per spin. If the sacks can be hung, a bottom plate for the cage is not necessary.

Any size of extractor can be modified by either one of the described methods. The 72-frame radial extractor mentioned earlier could probably spin 40-50 gallons (180-230 litres) of the comb and honey mixture from frameless hive harvests in 30 minutes. One person with a four-frame non-reversible extractor could still process about 10-15 gallons (45-70 litres) of the same mixture in 30 minutes.

Honey presses

Honey presses made from metal are not only slower than these modified extractors, but they are also more expensive, heavier, need special workshop equipment and good machining skills for their manufacture, and many have one fragile part that is difficult to replace. (A wooden press might be a useful alternative in many parts of the world.) Centrifugal extractors, however, can be made with ingenuity and a few spare parts. They are therefore cheaper, easier to repair, longer lasting, and faster. Their versatile use with traditional and modern beekeeping practices drastically reduces equipment costs in countries where beekeeping is in various different stages of development or where modernisation is planned in the future. Hobby beekeepers may also recognise here an easy, fast and efficient method for separating honey from cappings without heating.

In addition, it appears from our trials in Zambia that the spun honey has a lower content of pollen and the other fine materials characteristically found in large quantities in pressed honey’. It is also possible, however, that this was the result of more careful harvesting and grading during the sorting and cleaning stages.

Buying an extractor

For those who have to make equipment purchases with long-range planning in mind, these alternatives should make decisions much easier. Radial extractors only make sense in frame-hive beekeeping where wired frames with foundation sheets can be used. Since both wire and foundation sheets are generally hard to come by and are expensive, the more versatile non-reversible or even the reversible-type extractors with individual baskets are preferable. The two-frame extractors are generally too small for efficient conversion, while four- and six-frame extractors are only slightly more expensive and offer sufficient capacity for larger scale operations and community or co-operative projects. The larger volume cage also makes non-frame processing much faster and more efficient.

To simplify conversion for multiple use, imported or locally made extractors should have large baskets made of strong noncorrosive hardware cloth or wire mesh, with simple straight corners and a solid bottom plate.

I would not be surprised if many beekeepers have already used one of these modifications or another variation. If so, would like to hear some of your experiences and possible ideas for further improvements.

Rainer Krell is with International Consultancies for Environmentally Responsible Development (ICON), Rome, Italy.

1 inch = 2.54 cm

1 Krell, R; Persano Oddo, L:

Ricciardelli D'Albore: G. The influence of harvesting and processing methods on honey quality in Zambia and Malawi. In Proceedings of the Fourth International Conference on Apiculture in Tropical Climates, Cairo 1988. (1989) London. UK; IBRA.

This is an amended version of an article which first appeared in Appropriate Technology Vol 17 No 3, December 1990. The kind assistance of Intermediate Technology Publications is acknowledged.

* Please see the original journal article for images and diagrams of centrifugal honey extractors.