Bokashi Composting: How Does It Work?

Unlike traditional composting, Bokashi composting allows for the composting of all kitchen scraps, including those that are typically banned from aerobic systems like meat and dairy products. To Bokashi compost, mix your kitchen scraps with some of the inoculated bran, press them into the Bokashi bucket, cover them with another handful of bran, and then tightly cover the bucket. When the bucket is full, it is sealed shut and set aside for ten to twelve days to allow the waste to decompose. The leachate that is a byproduct of anaerobic composting needs to be drawn off every other day during that time. That’s the only care required. The Bokashi Bucket pickles food waste so that it is unrecognizable. At this stage, the “pre-compost” can be buried in an unused spot in the garden. One thing to be aware of is that it is still quite acidic and therefore plants roots should not come into contact with it for a couple of weeks.

During the 1960s, Dr. Higa was studying horticulture at the University of the Ryukyus in Okinawa, Japan. He became interested in the potential of using EM technology to improve plant growth and soil fertility. While studying the effects of microorganisms on plants, he discovered a combination of helpful microorganisms that he thought increased plant growth. After he graduated and completed his doctorate in horticulture, the university invited him back to become a lecturer in 1970. Two years later he became an assistant professor of horticulture, and then a full professor in 1982.

Most of his studies have focused on the effective microorganisms that he discovered and how they could be used in agriculture. The initial formula created by him, called EM-1, is used as an inoculant for bokashi bran used in bokashi composting, as well as for other agricultural purposes.

The process itself is a form of anaerobic fermentation. Waste is placed into an airtight container, typically with either a false floor to allow the drainage of bokashi juice (leachate) or with a secondary container beneath it to catch leachate. Bokashi bran is a combination of effective microorganisms (EM) that are used to inoculate the bokashi bin. The microorganisms in the EM Bokashi bran work together symbiotically and are specific to the needs of the bokashi bin.

The bucket is filled with bran, layered with inoculated bran, and topped off with a final layer of bran. It is sealed for at least two weeks to allow fermentation to occur. The fermentation process usually takes two weeks, but can be allowed to continue for a longer period of time. Excess bokashi leachate is drained off. After that, the resulting material is considered bokashi pre-compost and needs to be left to decompose using other methods.

Bokashi is a Japanese word meaning “fermented organic matter.” Some believe that the artistic reference to shading in Japanese also can be translated as “fading away” – a term that can also be applied to the bokashi fermentation process.

Bokashi is a new method of home composting in the western world, even though it is based on traditional practices. It has not yet managed to convince many people. Although there is a great deal of scientific evidence proving the usefulness of both regular compost and vermicompost, there is not yet enough evidence to support the use of Bokashi. The people who developed it in the eighties and who are marketing it today are still touting its virtues to a large extent. A majority of the studies that these companies reference, especially the U.S. company with close ties to Higa, seem to have only been announced at the conferences his group sponsored and only published on his affiliated websites.

Is Bokashi “Tea” Useful?

So far, studies done on the leachate have not been able to conclude whether it is beneficial to plants or not. Most studies don't find substantial benefits for plants from using this liquid in your garden. Although it may take some time, adding beneficial microbes to your soil will be beneficial in the long run.

Although the bokashi “tea” may not appear to be useful, it actually is. A recent study has found that feeding farmed fish, such as tilapia, a particular type of food may improve their health. An EM solution can also help to clean drains by breaking down the material that is stuck to the inside of the drain system. Possible benefits of adding bacteria to septic systems include faster decomposition of human waste and improved break down of food.

How to Use Bokashi?

The most common use for Bokashi is as an inoculant in anaerobic composting, but it can also be added to an aerobic compost pile, added directly to soil, or used to create compost tea for watering plants.

Getting Started

The Bokashi composting system is one of the most affordable options for composting. A commercial Bokashi bucket typically contains a five-pound plastic bin with a lid that fits snugly on top, as well as a spigot near the bottom. This spigot may be expensive at fifty dollars, but it could make the process much easier to handle. The leachate (liquid that drains from a landfill or other waste) needs to be poured off, and lifting a five-pound bucket full of soggy food scraps is beyond many. A kitchen baster can be used to make this process less messy.

The only other equipment you will need is Inoculated Bokashi Bran. You will usually receive a bag of it with your initial purchase, and replacements (2 pound bags) cost about fifteen dollars each.

The process is very simple. Bokashi bran is a fermented bran that is used to mix with kitchen waste, including meats and dairy products. You would mix it together, press it into a bin, sprinkle the bran over it, and then close the lid. A layer of plastic over the top of the pile will help it to stay sealed against the little bit of air left in the bucket. Obviously, large bones will not completely disappear within ten days. It is more efficient to cut up small bones and chop other items into small pieces according to the directions. If you don't chop the fruit, it will take a few extra days to ferment, and the larger pieces will turn into mush. To fill your bokashi bin, add 2 tablespoons of bokashi bran for every couple of inches of food waste until the bin is full.

The bin should be full before you cover it tightly and set it aside for ten days. It should be kept in a place where it's out of direct sunlight. Draw off half the liquid every day and use it as a fertilizer or to control slime in drains, pipes, and septic systems.

After about two weeks, the waste in the tub should be pickled properly. This method can be used to dig a fallow patch of the garden.

Maintenance

Bokashi is an anaerobic fermentation process. To keep it fresh, it needs to be free from oxygen. It is important to compress each day's waste into the container so that there are no air pockets and to avoid stirring up the previous day's waste when putting in new garbage. One site recommends using a plate to press the food-stuffs flat in the composter. This helps to increase the surface area that is in contact with the microbes, leading to faster decomposition. The plate protects the compost from contact with the air.

Regularly drawing off liquid helps maintain the environment needed by the bacteria that break down organic materials. That liquid needs to be used within 24 hours.

Troubleshooting

As usual, bad smells indicate that something has gone wrong. This diagnosis is more difficult than usual because Bokashi does not smell pleasant even when it is in good condition. The literature discusses the contrast between a “sweet and sour smell,” which suggests fermentation, and a “foul smell,” which suggests decay.

Bokashi does not produce the same offensive smell as other methods of anaerobic decay because the microbes used to inoculate the pile, such as yeasts and lactic acid producers, do not produce sulfuric acid.

There is no need to worry if you see white mold in the bin, but if you see blue, black, or green mold, it may be a sign that something has gone wrong and decay has begun.

If your Bokashi starts to decay, you can reverse the process by adding more Bokashi. This method isn't working. Start over by dumping the contents and cleaning the bucket.

After Fermenting…

The fact that the Bokashi mixture can be dug into the garden after fermenting for ten days doesn’t mean that the mixture is finished. The online description of the bin warns that plant roots should not touch it directly for a week or two; only after a month is it fully incorporated into soil. The Bokashi pre-compost that comes out of its bin is quite acidic, similar to the anaerobic compost that is produced by digesters.

Some people feed their vermicomposting worms pickled Bokashi material, which apparently causes no problems. The Bokashi process is very acidic, and worms are sensitive to acidic environments. However, worms do not seem to be affected by fermented feedstock.

Others put Bokashi pre-compost into their regular composting pile. Do not plant anything in the garden for at least two weeks after burying Bokashi. Burying it in the compost pile eliminates this need. This also solves the problem of finding space for a garden that is not being used. A Bokashi bin accelerates the composting process so that the material breaks down in about a month, as opposed to months when composting outdoors.

Who Should Do Bokashi Composting?

This particular composting method is well-suited for people who live in small spaces, such as apartments. It started in Japan and is now used a lot in that country as well as other Asian countries where there is not a lot of living space and composting can be hard.

If you want your compost to quickly disappear into your garden, this may be a great option for you. You will not be able to store the finished material and use it like regular compost, but you can still practice sustainability by reducing your household waste.

Frequently Asked Questions

Q: Is bokashi better than composting?

A: It depends on your goal. Do not use compost if you are looking to blend it into soil mixes or use it as mulch. If you want to reduce waste that goes to your local municipal waste-management facility, it is a great option.

Q: What can you not put in bokashi?

We recommend not adding large bones, lots of liquid oils, moldy food, or pet poop to your compost pile.

Q: How long does bokashi take to decompose?

Q: How long does it take for the contents of the pail to break down? A: Once the contents of the pail have fermented and you have buried the precompost, it typically takes at least 2 weeks to break down. Large volumes can take a bit longer.