Bokashi bran: what it is, and how to use it to compost
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Bokashi bran: what it is, and how to use it to compost
By Joe, Founder of Dr Forest · May 2026
A wedge of forgotten brie. A chicken carcass. Plate scrapings drowning in gravy. None of it belongs in a normal compost bin. All of it goes in a bokashi bucket.
Bokashi bran is rice or wheat bran inoculated with a culture of lactic acid bacteria, yeasts and photosynthetic bacteria, then dried for storage. You sprinkle a handful over kitchen scraps in an airtight bucket, press the lot down, and let the microbes get on with it. After two weeks of sealed fermentation, the food is pickled rather than rotted. Bury it in the garden or fold it into a compost heap and the soil will finish the job within about a month.
The system was developed in Japan in the 1980s by Dr Teruo Higa, a professor at the University of the Ryukyus in Okinawa, who isolated the microbe blend now sold as Effective Microorganisms or EM-1. The Dr Forest bran is rice-based and uses Dr Higa's original recipe, made under licence by an authorised UK manufacturer.
Bokashi is properly anaerobic. Traditional composting is aerobic. That single difference is why bokashi accepts inputs a normal heap won't touch.
What it is
Dried bran inoculated with EM-1, the effective microorganism blend developed by Dr Teruo Higa in 1980s Japan. Three microbe families: lactic acid bacteria, yeasts, photosynthetic bacteria.
What you do with it
Sprinkle a handful over each layer of kitchen waste in a sealed bucket. Press out the air. Drain the juice every few days. After two weeks of fermentation, bury or compost the pickled scraps.
What bokashi bran actually is
The bran is the carrier. It keeps the microbes alive and dry until you tip them onto a damp food scrap, at which point they wake up and get to work. The other two parts of the recipe are molasses and EM-1.
Molasses is the food source. The microbes are fed sugars during the inoculation stage so they multiply hard. The whole lot is then dried, putting them into dormancy until they meet moisture again.
EM-1 is the original microbe blend. Higa isolated it after years of work at Ryukyus University in the early 1980s, identifying the specific combination of lactic acid bacteria, yeasts and phototrophic bacteria that worked best in sealed fermentation, and standardising the recipe so anyone could buy it in a bag [1].
Three groups of microbes, doing different jobs
The blend works because the three microbe families overlap rather than compete. The chemistry they produce together is what gives finished bokashi its distinctive properties.
Lactic acid bacteria
Hundreds of billions per kilogram of fresh bran. They convert sugars into lactic acid, which crashes the pH of the food to around 3.5–4. That acidity preserves nutrients and suppresses the rot microbes that would otherwise produce foul smells. Same family that makes sauerkraut, yoghurt and kimchi.
Yeasts
Mostly Saccharomyces cerevisiae, the same strain used by bakers and brewers. Yeasts break down complex sugars into alcohols and esters, which feed the bacteria and give bokashi its faint bready, beery undertone. Optimum growth around 32°C, comfortably hit by most UK kitchens in summer.
Photosynthetic bacteria
A small population, but the ones that distinguish EM-1 from a plain lactic ferment. Rhodopseudomonas palustris uses organic acids as a carbon source, fixes small amounts of nitrogen, and synthesises amino acids that end up bound into the finished bokashi [2].
How fermentation differs from composting
A traditional compost heap is a slow fire. Aerobic bacteria break down food and garden waste, generating heat (a hot pile can hit 60°C in summer) and giving off carbon dioxide and water as the carbon in the food is metabolised. The lighter elements escape; the heavier nutrients stay behind, which is why a properly hot heap shrinks dramatically and smells earthy when it's working.
Bokashi is the opposite. Sealed away from oxygen, the EM microbes can't burn the food. They ferment it. Sugars convert to organic acids, the pH crashes from neutral to around 3.5–4, and the acidic, oxygen-free environment locks the food in stasis. Nutrients are preserved rather than oxidised. Spoilage microbes are suppressed by the acidity [3].
This is why bokashi handles things normal composting won't: meat, dairy, cooked food, even small bones. The acid prevents the smells and flies that would otherwise turn up.
The result after two weeks is a pickled pre-compost rather than finished compost. The food is largely intact in shape, soft, sour-smelling and chemically stable. That's the point at which it goes into the soil, where the rest of the breakdown happens aerobically and quickly.
Figure 01 · Process comparison
Aerobic versus anaerobic
A traditional compost heap is a slow fire. A bokashi bucket is a sealed pickle. The difference in process is what lets bokashi accept inputs the heap can't touch.
Compost heap
Aerobic
Open to air. Burns the food.
- ProcessMicrobes oxidise carbon to CO₂ and water
- Temperature40–60°C in a hot heap
- Time3 to 12 months
- InputsVeg matter, paper, garden waste only
- SmellEarthy when right; foul when wrong
- OutputCrumbly dark compost
Bokashi bucket
Anaerobic
Sealed. Pickles the food.
- ProcessMicrobes ferment sugars into lactic acid
- TemperatureRoom temperature throughout
- Time2 weeks ferment + 2–4 in soil
- InputsAll of the above plus meat, dairy, cooked food
- SmellSweet-sour, like pickle
- OutputPickled pre-compost; finishes in soil
Fig. 01. Heat and CO₂ leave the open heap; the sealed bucket retains carbon and acidifies instead.
How to use bokashi bran, step by step
Figure 02 · Anatomy
Inside the bucket
Six things going on at once: an airtight lid keeping oxygen out, layered scraps with bran on each pass, a perforated false floor, juice draining off through the tap, and the slow drop in pH that does most of the work.
-
1
Airtight lid + gasket
Open only to add waste. Each opening lets oxygen in and slows the ferment.
-
2
Layered food scraps
Cut to 5 cm pieces. Press each layer flat to expel air pockets before the next.
-
3
Bran sprinkle
A handful per inch of waste. Carries the dormant EM-1 microbes onto the food.
-
4
Perforated false floor
Keeps the contents above the juice well. Drains liquid down through the holes.
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5
Juice well (bokashi tea)
Cell water released by fermentation. Lactic-acid rich, dilute 1:100 for plants.
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6
Drain tap
Open every 2–3 days. Drain into a jug; use the same day before the live culture dies off.
Fig. 02. Cross-section through a 16-litre bokashi bin during the fill stage. Not to scale.
Figure 03 · Method
The seven-step routine
From an empty bin under the sink to a sealed, full bucket ready for the soil. Most weeks you only repeat steps 2 to 6.
Set the bucket up
Sprinkle a teaspoon of bran on the empty base to prime it. A two-bucket system lets you fill one while the other ferments.
Add scraps in layers
Cut to about 5 cm. Anything from the kitchen: cooked food, meat, fish, dairy, eggshells, coffee, small bones.
Sprinkle bran over each layer
Roughly a handful per inch of waste. If anything starts to smell off, double the bran on the next pass.
Press the air out
Use a potato masher or a piece of cardboard. The most underrated step: pockets of trapped air will spoil the batch.
Seal tightly between additions
Aim to add waste once a day rather than four or five times. Wipe the rim clean before resealing.
Drain the juice every 2–3 days
Catch in a jug. Dilute 1:100 with water and apply to plants the same day, or pour neat down the kitchen sink.
When full, leave sealed for two weeks
Start the second bucket. After 14 days the contents should smell sweet-sour, like pickle, and be ready to bury.
Fig. 03. Steps 2–6 are the daily loop. Steps 1 and 7 happen once per bucket.
Figure 04 · Fermentation timeline
What happens during the two weeks
From the moment the bran touches a damp scrap to a stable, sour-smelling pre-compost. The pH drop is the single most important indicator.
-
Days 0–3 · Activation
Microbes wake from dormancy
Moisture from the food rehydrates the EM-1 culture. Lactic acid bacteria multiply; sugars start converting to acid; cell water begins draining as juice.
-
Days 4–10 · Acidification
pH crashes from 7 to about 3.5
The ferment hits its stride. Yeasts produce alcohols and esters; phototrophic bacteria fix small amounts of nitrogen; spoilage microbes are out-competed.
-
Days 11–14 · Stabilisation
Pickled and chemically stable
White surface yeast is normal and harmless. Smell turns sweet-sour. Food shapes intact but soft. Now safe to bury or fold into the heap.
pH over the fermentation period
Indicative · not to lab scaleFig. 04. Three phases of the two-week ferment. The pH curve drops fastest between days 4 and 10.
What you can (and can't) put in a bokashi bin
Almost any food waste from a domestic kitchen is fair game. The airtight, acidic environment handles things that would turn an open heap into a fly nursery.
Figure 06 · Inputs reference
What goes in, what stays out
A quick visual reference. The acceptable column covers around 95% of what a domestic kitchen produces.
Goes in
Stays out
Fig. 06. The general rule: if it came from a plant or an animal and isn't already rotten, it can probably go in.
| Item | Bokashi? | Notes |
|---|---|---|
| Raw vegetable peelings and trimmings | Yes | Including alliums (onion, leek, garlic skins) that worm bins won't touch |
| Cooked food and leftover plates | Yes | Gravy-soaked, oily, salty, all fine |
| Meat and fish scraps, prawn shells | Yes | Cooked or raw. The fermentation handles both without smell or pest issues. |
| Small bones (chicken, fish, rib bones) | Yes, with patience | Will break down eventually but take far longer than soft food. Crush or chop to help. |
| Dairy: cheese, butter, yoghurt | Yes | Hard cheese rinds especially, anything a normal heap would reject |
| Bread, pasta, cooked rice | Yes | No risk of rats once the bucket is sealed |
| Citrus peel and skins | Yes | The acidity that worms dislike doesn't bother bokashi microbes |
| Coffee grounds, paper tea bags, eggshells | Yes | Crush eggshells lightly to speed soil-stage breakdown |
| Wilted cut flowers, indoor plant trimmings | Yes | Avoid woody stems thicker than a pencil |
| Free liquids (oil, sauces, milk by the pint) | No | They pool at the base and drown the microbes. Drain plates first. |
| Mouldy or already-rotten food | No | Competing microbes beat the EM strains to the punch |
| Whole carcasses, large beef, pork or lamb bones | No | Take many years to break down even after the soil stage. Use for stock first; compost the softened bones if you wish. |
| Hard fibrous waste (pineapple crowns, corn cobs) | No | The bulk doesn't soften enough in the bucket |
| Garden waste, grass clippings, leaves | No | Better suited to an aerobic heap; bokashi is built for kitchen waste |
| Pet faeces, used kitty litter | No | Pathogen risk; never use on edible-crop soil |
| Packaging, plastic-coated tea bags, stickers | No | Anything inorganic, regardless of how small |
That covers about 95% of what a household kitchen produces [4]. The general rule: if it came from a plant or an animal and isn't already rotten, it can probably go in.
When the bucket is full: what to do with the pre-compost
Figure 05 · Finishing the process
Three ways to finish the pre-compost
A full bucket of pickled scraps is not yet compost. Soil microbes do the second half. Pick whichever route fits your garden and the time of year.
Method one
Trench burial
Dig 20–30 cm deep in a bare patch. Tip the bucket in, mix lightly with the soil, then cover. The classic method.
Method two
Compost heap addition
Fold pre-compost into the middle of an existing hot heap. Pre-digested fuel: heats it up fast, accelerates breakdown, adds microbial diversity.
Method three
Soil factory
Layer pre-compost into a tub of garden soil at one part bokashi to three parts soil. Cover and leave. Result: a planting mix you can use straight into pots.
Fig. 05. All three end at the same place: dark, soft, well-fed earth. The route depends on what you have to hand.
Trench burial
The classic method. Dig a trench 20–30 cm deep in a bare patch of ground. An empty bed, between rows on an allotment, end of the vegetable plot. Tip the bucket in, mix lightly with the soil at the bottom, then cover. Leave two weeks before planting directly above. Soil microbes neutralise the acidity over that period and you'll be left with soft, dark, well-fed earth.
The speed of the soil-stage breakdown surprised me first time round. I went back to a trench a few weeks after burying a bucket-load, expecting to find half-broken-down scraps, and put the spade in to check. Just soil. Nothing left to recognise.
Compost heap addition
If you have a hot heap already running, fold bokashi into the middle of it. The pre-compost is pre-digested fuel: it heats the heap up fast, accelerates breakdown of the surrounding material, and adds a heavy dose of microbial diversity.
Soil factory
A planter or unused tub of soil works as a finishing chamber. Layer pre-compost into garden soil at roughly one part bokashi to three parts soil, cover, and leave for three or four weeks. The result is a planting mix you can use straight into pots and beds.
Worm bins also work, but go in slowly. Worms aren't keen on the initial acidity, so add a small amount and let them migrate towards it rather than dumping a whole bucket on top.
The juice at the bottom (bokashi tea)
The drainage liquid is a useful side product. Cell water released by fermentation drains down through the false floor and pools in the well at the base of the bucket. You'll have something to draw off after the second or third day of filling.
The juice has three practical uses:
- Diluted plant feed. 1:100 with water (about a tablespoon to a pint). Apply to the soil rather than the leaves. Use the same day, or the day after at the latest. The live microbes deteriorate fast once exposed to air.
- Drain cleaner. Pour neat down kitchen and bathroom drains weekly. The lactic acid and microbes break down grease and suppress smells. Commercial drain enzymes work on the same principle.
- Compost activator. Dilute 1:50 and water onto a slow heap to wake it up.
Don't store the juice. It's a live culture and goes off within 48 hours.
The soil finishes the work."
Common problems and quick fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| Putrid, rotten smell | Too much air; not enough bran | Press contents down hard, double the bran on the next layer, check the lid seal is clean |
| Black, blue or green mould | Aerobic mould has taken hold; too much oxygen or moisture | Scrap the batch and start over. (White fluffy mould on top is harmless yeast; carry on.) |
| No juice draining | Food load is dry, or contents have set rigid | Add a little water, or wait. A wetter food load will start to drain in a day or two. |
| Process feels slow in winter | EM microbes slow below 10°C | Move the bin indoors. UK kitchens at 18–25°C are ideal. |
| Fruit flies hovering | Lid not sealed properly between additions | Wipe the rim clean. Check the gasket. Don't leave the lid open while you scrape plates. |
Bokashi versus traditional composting
The practical differences come down to time, inputs accepted, and where the work happens.
| Traditional composting | Bokashi | |
|---|---|---|
| Process | Aerobic (needs oxygen) | Anaerobic (sealed away from air) |
| Time to finish | 3 to 12 months | 2 weeks ferment plus 2–4 weeks in soil |
| Heat generated | 40–60°C in a hot heap | Stays at room temperature |
| Smell when working | Earthy when right, foul when wrong | Sweet-sour, like pickle |
| Inputs accepted | Raw vegetable matter, paper, garden waste | Everything above plus meat, dairy, cooked food, small bones |
| Space needed | Outdoor heap or large bin | A 16-litre bucket fits under a sink |
| Carbon outcome | Significant CO₂ loss as material decomposes | Most carbon retained until the soil stage |
| End product | Crumbly dark compost, ready for use | Pickled pre-compost; finishes in soil |
| Maintenance | Turning, watering, balancing greens and browns | Sprinkle, press, drain, seal |
| Best suited to | Garden waste, paper, vegetable kitchen scraps | Flats, all-food-waste households, no-dig systems |
The two systems work well together. A bokashi bucket under the sink handles the kitchen side; a hot heap or wormery in the garden takes the rest. Co-composting bokashi with biochar has been shown to lift maize biomass by more than 200% over mineral NPK in tropical soils [5].
The Dr Forest bokashi range
Three products built around Dr Higa's original EM-1 recipe. Compostable packaging across the range. Handcrafted in small batches in Stockport, Greater Manchester.
- Dr Higa's Bokashi Bran. Rice bran inoculated with the original EM-1 recipe by an authorised UK manufacturer. £14 for the standard 1 kg bag; one bag covers six to eight full 16L bucket cycles depending on how generously you sprinkle.
- Dr Higa's Organic EM-1. The liquid culture itself, 1 litre. For activating your own bran, brewing bokashi spray for the garden, or topping up a slow ferment.
- Grow-Kashi. A probiotic soil conditioner: rice bran inoculated with the EM blend, then combined with fermented British biochar, volcanic rock dust, malted barley, mycorrhizal fungi and worm castings. Bokashi technology, applied directly to soil.
Browse the full EM & bokashi composting collection.
Common questions
What can you put in a bokashi composting bin?
Almost any food waste from a domestic kitchen, including the items that an aerobic compost heap or wormery refuses. Yes to: raw and cooked vegetable peelings, meat and fish scraps, dairy (cheese, butter, yoghurt), bread and pasta, citrus and onion skins, coffee grounds, tea bags and eggshells. Small bones (chicken, fish, rib bones) are fine but break down slowly even after the soil stage. No to: free liquids like oil and milk, mouldy food that's already rotting, large bones and whole carcasses, hard fibrous waste like pineapple crowns, garden clippings, pet faeces, and anything inorganic. The full table is in the section above.
How long does a bag of bokashi bran last?
A 1 kg bag typically does six to eight full bucket cycles, depending on how heavily you sprinkle. A two-person household putting all food waste through bokashi will use roughly 2 kg a year. Stored cool and dry in the original sealed bag, the bran keeps for 12 months without losing potency.
Can you use bokashi bran without a special bin?
Yes. Any sturdy, airtight bucket with a sealing lid will work. Drill a few holes in the bottom and stand it inside a second bucket to catch the juice; line the holes with a piece of cardboard if you don't want food slipping through. The dedicated bin design is convenient, not essential.
What does bokashi smell like when it's working?
Sweet-sour, like pickle juice or sourdough starter. Faintly bready or beery from the yeasts. If it smells putrid, sulphurous or like rotting meat, something has gone wrong, usually too much air or not enough bran.
Can bokashi pre-compost go straight onto plant roots?
No. The pH is around 3.5 to 4 when you tip the bucket out, which would burn most roots. Bury it 20–30 cm deep in soil and wait two weeks, or compost it first. After that initial period, soil microbes neutralise the acidity and the area becomes some of the richest planting ground you'll have.
Is bokashi tea the same as compost tea?
No. Compost tea is brewed from finished aerobic compost, usually aerated for 24 hours. Bokashi tea is the drainage juice from the fermenting bucket, used immediately at 1:100 dilution. Both feed soil biology, but they contain different microbe groups (aerobic versus anaerobic) and shouldn't be substituted for one another.
How does bokashi compare to a hot compost heap?
A well-managed hot heap finishes faster than a cold one but still takes three to six months and won't accept meat, dairy or cooked food. Bokashi handles all those inputs, finishes in roughly six weeks (two ferment, four in soil), and uses far less space. The hot heap produces a more universally usable end-product. The two systems work well together.
Can you make your own bokashi bran?
Yes, if you have liquid EM-1, molasses and a few hours. Mix the EM-1 with molasses and water, soak rice or wheat bran until evenly damp, pack tightly in a sealed bag for 10 to 14 days to ferment, then dry thoroughly. The home-made version is variable in quality compared to a commercially-fermented batch but works for budget-conscious gardeners doing high-volume composting.
Sources cited
- Park, H. & DuPonte, M.W. (2010). How to cultivate indigenous microorganisms. University of Hawaii College of Tropical Agriculture and Human Resources, Biotechnology & Bioengineering BIO-9.
- Mayer, J., Scheid, S., Widmer, F., Fließbach, A. & Oberholzer, H.R. (2010). How effective are 'Effective microorganisms (EM)'? Results from a field study in temperate climate. Applied Soil Ecology, 46(2), 230–239.
- Quintero-Herrera, S. et al. (2021). Optimization of bokashi-composting process using Effective Microorganisms-1 in smart composting bin. Sustainability, 13(8), 4304. PMC8073414.
- Royal Horticultural Society (2024). How to recycle food waste with bokashi. rhs.org.uk.
- Agegnehu, G. et al. (2019). Nutrient effect of various composting methods with and without biochar on soil fertility and maize growth. Archives of Agronomy and Soil Science, 65(11).