What Is Bokashi Composting and How Does It Work?

How bokashi works

Bokashi pickles your food scraps instead of rotting them. You layer scraps with bran that carries lactic-acid bacteria and yeasts, seal them in an airtight bucket, and those microbes ferment the food. The result looks almost like the food you put in, only softer and sour-smelling.

That is the key thing to understand. Bokashi is fermentation, not composting. A compost pile needs oxygen. Bokashi keeps oxygen out. The acidic, fermented scraps are then buried or added to a pile, where soil life breaks them down very quickly.

The name comes from a Japanese word usually translated as “fermented organic matter.” The method has been popular in home kitchens for decades because it is compact, fast, and handles foods most compost piles cannot.

What you need

• An airtight bucket with a spigot or drain. Kits usually come as two buckets, so one can ferment while you fill the other. Each holds about 4 to 5 gallons (15 to 19 L).
• Bokashi bran. Wheat bran, rice bran, or sawdust inoculated with microbes. You can buy it ready to use or make your own.
• A masher or flat plate to press out air.
• Somewhere to finish it: a garden bed, a compost pile, or a big tub of soil.

A homemade version works with two stacked food-grade buckets. Drill holes in the bottom of the inner bucket so liquid can drain into the outer one, and use a tight-sealing lid.

Step by step

1. Sprinkle a thin layer of bran on the bottom of the empty bucket.
2. Add scraps. Chop large pieces to about 1 to 2 in (3 to 5 cm). Add a layer at a time rather than a few pieces at a time.
3. Sprinkle bran over each layer. A small handful per layer of roughly 1 to 2 in of food is typical. Follow the amount on your bran package. Use more bran on meat, fish, dairy, and cooked food.
4. Press down firmly to squeeze out air pockets.
5. Close the lid tightly every time. Air is the main cause of failed batches.
6. Drain the liquid every 2 or 3 days through the spigot.
7. When the bucket is full, add a final generous layer of bran, seal it, and leave it alone for about 2 weeks at room temperature.
8. Finish it by burying it in a trench at least 8 in (20 cm) deep, mixing it into a compost pile, or mixing it into a tub of soil. After roughly 2 to 4 weeks, it is mostly unrecognizable.

Fermented bokashi is acidic when fresh. Wait about 2 weeks after burying before planting directly into that spot, or dig the trench between rows instead of under roots.

Bokashi tea

The liquid that drains out is called bokashi tea or bokashi juice. It is mostly water from the food, plus acids and microbes. Drain it regularly, because sitting liquid makes the bucket smell and can spoil the batch.

Always dilute it before use on plants. Roughly 1 part tea to 100 parts water is a common ratio, which works out to about 2 to 3 tablespoons per gallon (about 10 ml per liter). Undiluted, it is acidic enough to damage roots. Use it within a day or two of draining. It does not keep well.

What bokashi handles vs a backyard pile

Bokashi’s biggest advantage is range. It takes foods that attract pests and cause smells in an open pile.

Check individual items in the can you compost list. Bokashi is also a good partner for a worm bin. Buried bokashi or small amounts of well-fermented scraps can feed a worm bin, though worms prefer it after it has sat in soil for a week or two.

Pros and cons

Pros

• Takes meat, dairy, and cooked food that you should not put in a backyard pile.
• Fast: about 2 weeks in the bucket plus 2 to 4 weeks in soil.
• Compact enough for a kitchen or under a sink.
• Sealed, so no flies and no smell unless the lid is open.
• No turning, no balancing browns and greens.

Cons

• You need a place to finish it. Bokashi is not finished compost.
• You keep buying bran, or make it yourself.
• The bucket gets heavy when full, roughly 25 to 40 lb (11 to 18 kg).
• The smell when opened is strong and sour, which some people dislike.
• Fresh bokashi is acidic and needs a waiting period before planting into it.

What bokashi costs

Costs vary by region and brand, so treat these as rough ranges.

• Two-bucket kit: commonly somewhere around $40 to $100 including a starter bag of bran.
• Bran: often around $15 to $30 for a bag that lasts a household roughly 1 to 3 months.
• DIY buckets: a few dollars each if you reuse food-grade buckets from a bakery or deli.
• DIY bran: a bag of wheat bran plus a bottle of microbial liquid and molasses, usually well under the cost of bought bran per batch.

Ongoing cost is mostly bran. If that bothers you, a worm bin has no running cost once set up.

Troubleshooting

For bad smells in regular compost, see why does my compost smell.

Next step

If you have limited space, compare bokashi with worm bins and drop-off programs in composting in an apartment. If you have a yard, bury your bokashi in beds or mix it into a pile following how to start a compost pile.