Sometimes, the supply of fresh foods for black soldier fly larvae may not be as steady as we want. Maybe the food spoils before the BSF have a chance to munch on them. A way to solve this is to make longer-lasting food that is both odor-free & nutritional for the baby larvae. Let's have some fun checking out the fermenting method and let's see right below:

Fermenting the Foods

Fermenting the foods for the larvae extends the storage time for up to 6 months. This means we can store the foods for a long period of time without worrying about mold/houseflies or foul smell. Perhaps in a year, we only need to prepare the foods twice. When fermented, it will give off a slight acidic smell that's totally bearable & doesn't stink. This method is suitable for farms or someone who raise BSF indoors near residential areas.

The recipe we'll use today is:

  • 40 gram EM/ lactic acid bacteria /bread yeast
  • 1 kg wheat bran/rice bran
  • 80 kg yam/potato/soybean waste/cassava tuber
  • 200 gram sugar/molasses
  • 40 liters of water

If you'd like to see how to make your own EM or lactic acid bacteria easily at home, check out this post later:

>> Blog post: How to make EM1 effective microorganism (3 secret recipes)

Why Add Yeast?

To ferment 80 kg food waste, we'll have the yeast/fermentor or EM. You can use pre-made packages or make your own. These are the little microbes that get the work done fore us. Those that work best for this are Lactobacillus, Bacillus, Streptomyces, Saccharomyces. Basically, these are our little mighty warriors. Once they are released into the food waste, they'll do much of the heavy-lifting for us–chewing the food, breaking it down into smaller pieces & eliminating the smelly smell for us. Thus, also making the foods last longer in the acidic environment that they've created.

What Is the Wheat Bran For?

Wheat bran, rice bran or rice water really helps in activating these guys. Anything with a good amount of starch will do. The sugar or molasses will be the food for the microbes & helps keep the fermentation process going. If you can't find molasses around your area, sugar cane juice or other types of sugar is also fine.

Mixing the Foods

In a 120-liter bucket, mix in these components. You can use a heavy-duty electric mixer to save time & effort. Once the mixing is done, place the bucket in a cool, shaded area with a lid on top. In the first week, remember to open the lid slightly to let off some CO2 gas, a by-product of this fermentation. Then, you can let it sit there & take out some food for the BSF larvae anytime you see fit.

Using the Foods

Some people use the foods when it's about 10 days old. You can let it soak for longer. You may see some white film or fuzz at the top surface & this is completely normal. It won't harm the food source. In simple words, this is like pickles. When you like it, you can take it out for consumption. The foods won't spoil if kept in these conditions.

Make BSF Food Last Longer

The benefit of making the fermented food for BSF larvae is the acidic environment it creates. This acidity makes it nearly impossible for other life forms to survive, except for the very hardy good microbes. The foul smell will also be reduced.

Houseflies, the main cause of your loved ones saying 'Oh it stinks, get it out of the house please', won't be buzzing around anymore. Best of all, the foods will retain most of their nutritional value, they can be kept for longer & will be easier to digest for the larvae.

Have fun exploring & share with us some tips you have. Enjoy! But one last note, don't turn them drunk by alcoholic fermentation. But it's your call after all.

Responses to Readers' Questions

Thanks for this post. As you said "anything with a good amount of starch will do", what can cassava tuber replace in this recipe.

--> Thanks for your question. Cassava tuber has a good amount of starch in it so it could be a replacement for the wheat bran and even the potatoes or yam. From my little knowledge, growers have implemented feeding the BSF with both fresh cassava tuber and cassava waste. The cassava waste does not seem to be as good because they have already squeezed out most of the nutrients in it. The fresh tuber gives good results. BSF eat the cassava flesh inside but not much of the outside skin. As the fresh ones may be quite hard, I think fermenting could make them softer. Thus, easier for the larvae to chew.

Here's the cassava waste people use. They also face a problem with mold. Fermenting could help with this for longer storage.

Cassava feed with some mold developing | Source

In the pic below are the larvae (15 days old) on cassava waste. The grubs grow quite slowly. They are still cream but should have turned black into pre-pupae at this point:

Cassava feed 15-day-old larvae

And here are the BSF enjoying fresh cassava. People use this 'hard' food (unlike soft fruits like mango or papaya which get consumed in a heartbeat) to stretch the eating time. This helps fight hunger in times of food shortage, which prevents the BSF from crawling out of the bin & pupate prematurely. Which could lead to high death rates hours after their pupation.

BSF larvae eating fresh cassava | Source

All in all, if you have good nutrient-packed ones, cassava would be a great choice! I hope this helps.

Yo tengo Disponible estiércol de codorniz y lo que quero es evitar el amoníaco es posible con estas bacterias?

I have available quail manure and what I want is to avoid ammonia is it possible with these bacteria?

--> Thanks for your question. For reducing the foul smell including the ammonia of fresh manure (chicken, pig, cow, ox, etc.), growers do apply the EM bacteria. Likewise, I think it is possible to use for quail manure and you should give it a try to observe the results for your environment.

If you want to reduce the smell and ferment the manure, a recipe that a grower shares is about 70% fresh manure, 30% spacers (for example peanut shells, rice husks, wood chips, carbonized rice husks, rice bran) + several bags of microbial composted manure + EM bacteria or trichoderma (a decomposing fungi that don't like too much heat). Some additional molasses would also be great. In ratio, for 2 tons of quail manure, you can use 2-4 bags (25 kg per bag) of microbial composted manure and 1 kg of trichoderma. More or less is okay.

With this method, you can "cold ferment"/compost the quail manure without needing a tarp to cover it. Depending on how much bacteria/fungi used, it can be done as quickly as 15 days. The key points are to add aeration spacers for fast break-down, not pile it up too thick (the heat could kill some beneficial fungi) and stir the it often. Mist some water if it gets too dried. The smell will be reduced and you are left with nice, nutrient-rich composted material to use for your garden or feed the BSF. You can see the process here:

composting process in 15 days

If you just want to avoid the ammonia smell and and not fermenting the food, another way you can try is to spray the bacteria mixed in a solution onto the quail poop. Folks use store-bought EM and mix it with molasses and water. It could work relatively quicker than the method I've shared above. From my limited experience with cow manure, the ammonia seems to dissipate as we let it air out for a couple of days. However, your experience may differ. I hope this helps!

Hi, can I use Kombucha and its SCOBY in place of yeast?

--> Thanks for your question. To be honest, I haven't tried it. But imho, if there are already the bacteria & yeast in the liquid kombucha and the solid SCOBY, then maybe it could work. Not sure about the amounts so you could experiment with it some more. Let us know how it goes if you'd like!

Side note: This reminds me of the fermentation of soap nuts (with pineapple) to make GE (garbage enzyme) for cleaning. When the GE SCOBY is formed, they keep some of it to start the next batch.    

So-called GE SCOBY with soap nuts | Source

Good luck with your BSF raising!

What is microbial composted manure. The one you mention in the paragraph about fermenting manure?

--> Thanks for your question. It is composted organic matter with some microbes added in. In my country, they sell pre-packaged bags like this:

A bag of manure | Source

It is basically organic matter fermented with beneficial microbes. The carriers for the microbes could be cow/duck/goat manure, coffee bean shells, sugarcane waste, etc. As those things break down, I guess people collectively call them "manure" in our language.

They use nitrogen-fixing bacteria, some bacteria that break down cellulose, phosphorous, and fungi. The usual amount is 1 x 10^6 CFU/g for each type of bacterium (I am not an expert scientist or anything but that is what's printed on the back of the bag). From what I can see, a bag contains about 15% organic matter, 30% moisture and a pH of about 5. Just to give you some more specifics.

For the process I was talking about, you could check out this video:

composting process in 15 days

Not sure if this answers your question, hope it clarifies!

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