Gassy build-up

Sandi Bryant asked 6 years ago

Hi Nick. I’m super-excited to have found your website! Wow, what a mine of info and the videos make it super-easy to understand. I live in South Africa and have just filled my first Bokashi bin. Throughout the process, I’ve noticed that the lid of the bin seems to “blow” a little between feeding. (I only feed it every 3 or 4 days.) I’ve just been sprinkling the bran on top of the food, pressing down but not mixing it through as you showed in your video. Should I be doing that rather> Also, I do harvest the tea (I have to tip the bin) but there’s not too much and it does smell a little stinky?! Thanks again and I look forward to your advice and will be sharing your URL with family and friends 🙂

3 Answers
Nicki Casley Staff answered 6 years ago

Hi Sandi,
Glad to hear that you are enjoying the website. Feel free to share it far and wide. The more people we can get composting their food waste, the healthier and more productive our soils, and the smaller our landfills 🙂

In response to your gassy build-up question! You shouldn’t be getting any significant gasses produced from the fermentation process. It is an indication that some putrification (rotting) is happening in the bin. This may happen for a few reasons:

1. The layers of food waste are more than an inch deep. In this case, the food waste near the centre of the layer may start to putrify slightly before the bokashi microbes can work there way through to it. Mixing the food waste can help, or just add the food waste in thinner layers to make sure the bokashi bran is well distributed.

2. The food waste is not chopped small enough. Again, this may mean that the bokashi microbes take a bit longer to get to the centre of your food scraps and some putrification may be happening. We recommend chopping food waste to less than 2″ in size.

3. There’s not enough bokashi bran. Try being a bit more generous with the bokashi bran each time you add food waste. We typically recommend adding 1-2 tbsps of bokashi bran for each inch of food waste. But if you are adding harder to compost items such as meat, bones, dairy and cooked food then we would recommend being more generous. Similarly, if you aren’t able to chop you food waste into small pieces then you should add an extra sprinkling of bran.

4. The bokashi bran is old or poor quality. When stored correctly at room temperature and out of direct sunlight, bokashi bran should remain effective for up to two years. If you consistently get gassing and bad smelling bins, I would recommend contacting your bokashi bran supplier.

In terms of the tea. It does have a smell, but it should be pickly (like the bokashi’d food waste). Try to empty the reservoir every day or two to make sure that it stays fresh. Again, bad smelling tea may be a sign of some putrification happening in the bin.

If you are getting ‘too much’ tea then you can simply pour it down the drain. The bokashi microbes are great for our drains and will help unblock slow or blocked drains and sinks. Some people recommend freezing excess tea for use during growing seasons. However, freezing will reduce the number of healthy microbes in the bokashi tea and not everyone wants to store frozen ice cubes of bokashi tea in their domestic freezer.

I hope that (rather long!) answer is helpful. Feel free to ask any more questions you may have here.
Happy composting,
Nicki and the Bokashi Living team

isabel answered 3 years ago

Hi! I also recently started my first bin (2.5 weeks ago) and have been mostly adding citrus rinds among other veg. I always cut the pieces to < 0.5″ and mix 1tbsp bran per 2″ layer (sometimes 1tbsp for 1″ layer) and mix in the bran with the new scraps without disturbing the previous layer. I always press down with my hands and then cover with thin plastic bag before sealing and pressing out as much air from the lid. 

The past week though, the lid has been bulging when I am about to add more scraps. I add scraps about every 1-2 days. It’s been kept at room temperature, in the dark, under the sink (about 65-70F). It smells what I would describe as pickley, and just got the first batch of tea yesterday (it’s otherwise been dry the whole time). I’ve only halfway filled the container in these 2.5 weeks. 
Is the gassing something to worry about? Or how else can I address this?

Nicki Casley Staff answered 3 years ago

The gassing as you describe it is not uncommon, and i don’t think you need to worry about it at that level.   If everything goes correctly and the microbes have good access to all of the food waste, there should be no gassing happening however.  But it can often be that the bokashi is not sprinkled evenly enough, and so the microbes have a harder time getting all through the food waste.  When this happens, some level of rotting can occur, and this creates the gas.  In time, the bokashi microbes should outcompete the rotting microbes, and reverse the process on their own.  But if you want to avoid any gassing, then the best you can do is to try to get a good even sprinkling of bokashi throughout the food waste.  This will make the microbes job easier and faster.  Tip:  if you use a shaker jar for your bokashi bran (like a parmesan cheese shaker, or even a spice jar) it will help you get a good even sprinkling.  It is also more efficient because with a more effective ‘sprinkle’ you can usually get away with using a little less bokashi bran.

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