The domestic Bokashi system originated in Japan and offers a means of dealing with cooked food at home avoiding the need to send it to landfill or having it collected by the council. Materials such as eggshells and bones can be decomposed
in a Bokashi bin but will take longer to breakdown and are probably best dealt with using a Green Cone. They also provide an excellent way of converting cooked food into a material that can be composted in a conventional compost bin.
Bokashi bins can
be kept in the kitchen or outside in a shed or garden. However, in colder conditions the fermentation process slows down, so it should be left to digest for a longer period (e.g. for three weeks or more instead of two). If kept outside the house an outbuilding,
such as a shed, or even a garden storage box would keep it out of the rain, sun and protect the bin from frost.
The system involves anaerobic fermentation rather than the aerobic action of microorganism in conventional composting. It requires the addition
of “Effective Microorganisms” (EM) which are a mixture of bacteria and yeasts to break down the food waste. These microorganisms will normally include yeasts, (Saccharomyces spp.), lactic acid producing bacteria (Lactobacillus spp.),
and phototrophic bacteria (Rhodopseudomonas spp.)
The purchase of this bran will cost in the region of £40 - £50+ per year whereas most of the conventional food composters will not have any running costs.
often described as a composting procedure the bokashi bin is frequently used as a pre-composting process with the product being added to a regular compost bin or buried in the garden. The material can be buried in a hole but I feel that it
is best to use the Trench composting method where a 30cm (1ft) deep trench is dug to bury the Bokashi product (often with the addition of uncooked kitchen waste) this can be left over winter to make a bean trench.
commercially available Bokashi Bin normally consists of a plastic bin with carry handle, airtight lid and drainage tap. It has an inner drain tray to allow separation of the food scraps and liquid produced by the system and to prevent the solid
material blocking the drainage tap. It will often come with a measuring scoop, a push tool and even a liquid drain cup. Some homemade systems do not include a drainage tap.
The microorganisms are introduced by spreading Bokashi bran thinly on the base
of the bucket and over the food during the pickling process. Some systems recommend putting two or three spoonfuls of Bokashi bran into the bottom of the bucket before adding the initial layer of food waste This is most helpful when a system
is being used that does not include drainage. The food should be added in small pieces to form a layer about 3-4cm thick. Any large pieces should be cut to 3-4 cm to enable the microorganisms to ferment the food effectively and speed up the process. If possible,
use fresh food. The Bokashi system will deal with food contaminated with white mould but green or black. Scatter about a measure or tablespoon of Bokashi bran the top of the layer of waste food and compress it by pressing down with the tool provided or a potato
masher to remove air pockets. Cover with cardboard, plastic to exclude air and close the bin lid. Drain off the Bokashi juice every couple of days.
Repeat the layering process alternating food waste and bran as the waste becomes available, remembering
to seal the bucket to exclude the air on every occasion seal until the bucket is full. Once full leave the Bokashi bin closed and undisturbed for two weeks or more, remembering to drain off the juice every other day.
Two Bin Systems
To work, effectively the system requires the use of two Bokashi bins. The bin in current use is normally kept in the kitchen so that plate scrapings and other food waste can be added directly to the bin. Once full, the bin is set aside for two weeks
and the second bin brought into use.