Making Your Own Bokashi Bran
Kitchen Scrap Fermentation for Better Compost
If you're composting kitchen scraps, you've probably hit the same frustrations: it smells, it attracts flies, you can't put in meat or dairy or cooked food, and it takes ages to break down. Enter bokashi—a Japanese fermentation method that solves all of these problems.
Bokashi isn't traditional composting. It's actually fermentation—you're pickling your kitchen scraps using beneficial microbes. The process is anaerobic (no oxygen), happens indoors in a sealed bucket, takes just 2-3 weeks, and you can put literally everything in it: meat, fish, dairy, citrus, onions, cooked food, even small amounts of paper.
The magic ingredient? Bokashi bran—grain inoculated with beneficial bacteria, primarily lactobacillus (yes, the same family as in your sauerkraut and kefir). You sprinkle this bran over your scraps as you add them, and the microbes ferment everything into a nutrient-rich pre-compost that breaks down incredibly quickly once buried in soil.
Commercial bokashi bran is expensive—often $25-40 per bag. But here's the thing: if you're already comfortable making fermented foods, you can make your own bokashi bran for a fraction of the cost. It's the same principles you already know, just applied to garden waste instead of food.
Why Make Your Own?
Cost: A batch of homemade bokashi bran costs $5-10 and lasts for months, versus $25-40 for commercial products.
Control: You know exactly what's in it—no mystery ingredients, no fillers, no concerns about quality.
Connection: If you're making milk kefir or yogurt, you've already got the perfect inoculant in your whey. Why buy expensive EM (Effective Microorganisms) solutions when you've got beneficial bacteria right in your fridge?
Flexibility: Once you understand the process, you can adapt it—use different grains, adjust moisture levels, scale up or down.
The Fermentation Connection
If you make sauerkraut, kimchi, or milk kefir, you already understand what's happening here. You're creating an environment where beneficial bacteria thrive and harmful ones can't survive:
- Lactobacillus bacteria dominate the fermentation (same as in your kraut)
- The low pH (acidity) they create suppresses pathogens and prevents putrefaction
- Anaerobic conditions (no oxygen) favor the good guys
- The result is preserved, pre-digested organic matter—fermented rather than rotted
The only difference is you're applying these principles to kitchen scraps instead of vegetables.
What You'll Need
For the bran:
- 5kg wheat bran (or rice bran, or a mix—find it at stock feed stores, health food shops, or brewing suppliers)
- 500ml water (approximately—you'll adjust by feel)
- 3 tablespoons molasses or brown sugar
- Inoculant (see options below)
For the inoculant, choose one:
- 500ml whey from milk kefir, yogurt, or cheese-making (my preferred method)
- 500ml lactobacillus serum from fermented rice wash water (see our recipe)
- 500mls of Kraut juice or any liquid from your vegetable ferments - we sell ours in 480- 1 litre pouches.
- Commercial EM-1 or bokashi starter (if you don't have access to the above)
Equipment:
- Large bucket or tub for mixing
- Airtight container or heavy-duty plastic bags for storage
- Tarp or large sheet for spreading/drying
How to Make Bokashi Bran
1. Prepare your inoculant mixture
Mix your whey (or other inoculant) with the water and molasses. The molasses feeds the bacteria and helps them survive during storage. Stir until the molasses dissolves.
If using milk kefir whey, you're basically adding millions of lactobacillus bacteria that are already active and hungry. Perfect.
2. Mix with the bran
Put your wheat bran in a large bucket or tub. Pour the liquid mixture over it gradually, mixing thoroughly with your hands as you go. You're aiming for the consistency of a wrung-out sponge—moist enough that it clumps when you squeeze it, but not so wet that water drips out.
This is exactly like judging moisture for making kraut—you want it damp, not sodden.
3. Pack it down
Once everything is evenly moist, pack the bran firmly into an airtight container or heavy-duty plastic bag. Press out as much air as possible if using a bag. You want anaerobic conditions—no oxygen.
4. Ferment
Leave it at room temperature for 2-3 weeks. You'll notice:
- A sweet-sour smell developing (like sourdough or yogurt)
- Possible white mold on the surface (this is good—it's beneficial yeast)
- The bran might warm up slightly as fermentation kicks in
If it smells putrid or rotten, something went wrong—too much moisture or contamination. Start again.
5. Dry it out
After 2-3 weeks, spread the fermented bran on a tarp or large sheet in a well-ventilated area (not in direct hot sun). Break up any clumps. Let it dry until it feels like slightly damp sand—not bone dry, but dry enough to store without going moldy.
This can take 1-3 days depending on humidity and airflow. You can speed it up with a fan.
6. Store
Once dried, store in an airtight container. It will keep for 6-12 months. It should smell sweet and fermented. If it starts to smell musty or off, it's gone bad.
How to Use Bokashi Bran
Setting up your bokashi bucket:
You need two buckets (about 10-20L each) with tight-fitting lids. One sits inside the other, with holes drilled in the bottom of the inner bucket so liquid (bokashi tea) can drain through. Or buy a commercial bokashi bucket with a tap at the bottom.
The process:
- Add kitchen scraps - any food waste except large bones or excessive liquid
- Sprinkle with bokashi bran - a good handful (about 2 tablespoons) over each layer of scraps
- Press down firmly - push out air pockets, compact the scraps
- Seal the lid - keep it airtight between additions
- Drain the liquid every few days - this "bokashi tea" is excellent plant fertilizer diluted 1:100, or pour it straight down drains to keep them clear
What you can put in:
- All fruit and vegetable scraps
- Meat, fish, bones (small ones)
- Dairy products
- Cooked food, bread, pasta
- Coffee grounds and tea bags
- Egg shells
- Small amounts of paper towels or napkins
What to limit:
- Excess liquid (squeeze out first)
- Very large bones
- Already moldy or rotten food
After 2-3 weeks:
Once your bucket is full, seal it and leave it for 2 weeks. Then:
- Bury it in your garden - dig a trench, add the fermented scraps, cover with soil
- Mix it into compost - it will break down incredibly fast
- Add to worm farms in small amounts - worms love fermented scraps
Within 2-4 weeks of burial, it will have completely broken down into rich, fertile soil.
Troubleshooting Bokashi Bran
It smells rotten during fermentation: Too much moisture or contamination. The mixture should smell sweet-sour, like pickles or yogurt, not putrid. Start again with less liquid.
Nothing seems to be happening: Could be too dry, too cold, or your inoculant wasn't active. Try again with more liquid or in a warmer spot.
Blue or black mold: This is bad mold—contamination. White mold is fine (beneficial yeast), but colorful mold means something went wrong. Discard and start over.
It won't dry out: Too much moisture to begin with. Spread it thinner, use a fan, or put it somewhere warmer with good airflow.
Troubleshooting Bokashi Process
Bucket smells rotten: Not enough bran, or air is getting in. Use more bran per layer and check your lid seal.
Black or fuzzy mold in bucket: Normal! Small amounts of white mold are beneficial yeast. Black fuzzy mold means contamination—usually too much air or not enough bran.
Fruit flies: Lid isn't sealed properly, or you're not covering scraps thoroughly with bran.
Nothing's happening: Bran might be old or inactive. Try fresh bran or add more per layer.
Using Milk Kefir Whey as Inoculant
This is my favorite method because if you're already making milk kefir, you've got perfect inoculant just sitting there. The whey from straining kefir cheese or Greek-style kefir is packed with lactobacillus bacteria—exactly what you need.
Why it works:
- Lactobacillus bacteria are the stars of bokashi fermentation
- Your kefir whey is already acidic, which helps
- It's free if you're making kefir anyway
- Same bacteria, different application
To use: Simply substitute 500ml of kefir whey for the inoculant in the recipe above. If your whey is very thick, dilute it slightly with water. Otherwise, follow the same method.
You can also use whey from yogurt-making or cheesemaking—any acidic whey that's resulted from lacto-fermentation.
Using Sauerkraut juice (the brine) as an innoculant
Easy and also readily available in your kitchen - this is full of lactobacillus bacteria—it's lacto-fermented just like kefir whey. Same family of beneficial bacteria, slightly different strains, but they'll do the job perfectly well.
The considerations:
Salt content: Sauerkraut brine is typically 2-3% salt, which is higher than whey but not problematic. The bacteria in bokashi can handle that level of salt without issue. If you're using very salty brine (like from a long-fermented kraut), you might want to dilute it slightly with water.
Acidity: Sauerkraut juice is already acidic (low pH), which is exactly what you want for bokashi. That acidity helps the beneficial bacteria dominate.
Bacterial diversity: Sauerkraut brine might have a slightly different mix of lactobacillus species than milk kefir, but they all produce lactic acid and create the right conditions for bokashi fermentation.
To use it:
Just substitute 500ml of sauerkraut brine for the whey in the recipe. If your brine seems particularly salty or concentrated, you could do:
- 250ml sauerkraut juice
- 250ml water
- 3 tablespoons molasses
Mix with your wheat bran and proceed as normal.
Other fermentation liquids that work:
- Kimchi juice (although the spices might add interesting character and smell!, I'd rather use it for cooking or drinking.)
- Pickle brine from lacto-fermented pickles (same as the kimchi juice really - use it as a hydrolite)
- Water kefir
- Whey from any fermented dairy
Basically, any liquid from a successful lacto-fermentation will have the right bacteria. It's all the same principle—just different starting materials.
Scaling the Recipe
The ratio is approximately:
- 10 parts bran
- 1 part liquid mixture (water + inoculant + molasses)
So for a smaller batch:
- 2.5kg bran
- 250ml total liquid (water, whey, and molasses)
For a larger batch:
- 10kg bran
- 1L total liquid
Adjust based on how the moisture feels—you're aiming for that wrung-out sponge consistency.
Notes:
Bokashi composting is fermentation applied to kitchen waste—same principles, different outcome. Instead of sauerkraut, you're making pre-compost. Instead of probiotic food, you're creating probiotic soil amendment.
If you're already comfortable with fermentation, making your own bokashi bran is straightforward and saves serious money. Use the whey from your kefir or yogurt, mix it with grain and molasses, ferment for a few weeks, and you've got months of supply.
It's a beautiful closed loop: your milk kefir whey inoculates the bokashi bran, which ferments your kitchen scraps, which feeds your garden, which grows your food. That's the kind of resourcefulness that makes sense.
See also: Fermenting Rice Wash Water for the Garden | Making Milk Kefir | The Science of Fermentation
