Bokashi bins boost hot compost

When it comes to boosting the composting process, we have found a Bokashi bin to be the perfect partner for the Green Johanna.

We recently carried out trials involving additions of fermented food waste from a Maze Bokashi bin to a Green Johanna and found that temperatures in the Johanna rapidly increased as a result.  

For our trials, we re-started a Johanna more or less from scratch, having previously removed large amounts of compost.  Using a permanently installed insulation jacket and large amounts of Bokashi bran and carbon-rich materials, compost temperatures were around 30 degrees Celsius. 

 We added the contents of a Bokashi bin that had been fermenting for 21 days, followed by a full 1kg bag of Bokashi bran.   We then added some mulch and stirred well with a garden fork, before completing the process with a thin layer of mulch. 

 The Johanna was then left for 48 hours.  Temperatures rose to 66 degrees Celsius whilst outdoor temperatures were in the 0-10 degree range.   After 48 hours we re-stirred to spread heat more widely through the Johanna.    Using two Bokashi bins in rotation we repeated this cycle roughly every three weeks and got the same results.

We used the Green Johanna in combination with a regular kitchen caddy (as the Johanna needs regular feeding to maintain the hot composting process), twin-bin Bokashi system, Insulating Jacket, Bokashi Bran as an accelerant and plenty of mulch.

Photos show starting temperature at 30 degrees Celsius/adding fermented waste from a Bokashi bin/ adding Bokashi bran/temperature at 66 degrees Celsius.

The Bokashi process was developed in Japan in the 1980s; the term means ‘fermented organic matter’ in Japanese.  It involves adding all your food waste, cooked and uncooked, to a specially designed airtight Bokashi bin, with the addition of Bokashi in the form of a fermented bran or spray. The food waste is compressed with a compactor to eliminate as much air as possible as this is an anaerobic process.  Once the bin is full, you close the airtight lid and leave for 2-3 weeks.  Many people use two or three bins to keep the process going.

The bacteria (lactobacilli) in the bran or spray will create lactic acid which will effectively pickle the food waste rather than letting it decompose as it would in a regular food waste caddy.  After a week or so, liquid should start to form in the Bokashi bin which should be drained using the tap.   This ‘Bokashi tea’ can be used as a drain cleaner or diluted for use as plant food.

 At the end of the fermentation period the waste food is a pre-compost mixture that can be added to a composter or buried in soil to become a soil enhancer. Its composition is such that virtually all its original nutrients, carbon and energy enter rapidly into the soil.   No greenhouse gases are released to the atmosphere as they are during regular food waste decomposition in landfill.

Bokashi composting has traditionally proven particularly popular in urban environments where traditional garden composting is difficult. 

Mark

Helping the planet by switching to bokashi

Man emptying food into a bokashi bin

My parents and I were discussing the fact that their local council doesn’t yet operate a separate food waste collection.

My mum said it wasn’t a huge deal for them because they didn’t have any food waste anyway.

 I queried this; they must have food waste.  She maintained that they didn’t.

I said I wondered if they ate eggshell sandwiches, or tea bag pie, or perhaps apple core crumble. She said she wondered if I was being sarcastic.

Of course, they didn’t eat those things, she said, but that wasn’t waste ‘because you couldn’t eat it anyway’. It became clear that the word ‘waste’ meant different things to each of us.  

‘Our generation sees waste as something you scrape off your plate,’ Mum said. ‘So it’s the result of not planning properly and cooking too much or putting too much on your plate.’

My parents’ generation of ‘war babies’ equate the word waste with wastefulness.

Wasting food

This might go some way towards explaining the confusion that arose some years ago when research was being done to establish what residents’ attitudes would be if their local council offered voluntary food waste collections. Researchers found that many people said they wouldn’t use a food waste collection because they had no food waste. This didn’t stack up as it didn’t equate to the amount of food waste that the councils had to dispose of. Perhaps these respondents were people of my parents’ generation who thought that if they weren’t ‘wasting’ food they had no food waste.

After our discussion, Mum started thinking about everything she threw in the bin. She realised that she created large amounts of peelings because she makes fresh soup every day.

The next time I visited, she said that because they didn’t yet have any information about when their council would start food waste collections, it had been preying on her mind that every scrap in their bin went to landfill.

But they also felt ‘too old at our age’ (81 and 84) to start stirring compost.

Starting with the belief that you’re never too old to save the earth, I came up with a solution – Team Bokashi. It would work like this:

  • A Maze bokashi bin indoor composter would fit neatly on their worktop, or under the sink, and they could scrape all their food waste into it.
  • By adding bokashi spray to each input of food waste, natural beneficial microbes are introduced which accelerate the fermentation process. (Bokashi is Japanese for ‘fermented organic matter’).
  • Because the waste ferments anaerobically (without air), there are no flies or smells.
  • Once the 14L bin is full, it is left sealed shut for two to three weeks while the contents are left to ferment. Then the contents would normally be added to a garden composter, where it acts as an accelerator, or buried in the garden to break down and become soil-building compost. But I don’t see my dad at 84 being keen to go round digging holes in his garden, so I said I would take the bin and add its contents to our own Green Johanna or Compost Tumbler and hand it back to them. Using two bins on rotation should do the job.

In a way, it’s our own version of what the ShareWaste app does – connecting people who would like to recycle their food scraps with other people who are already composting.

My dad came on board when I explained that the liquid you drain every few days from the tap at the bottom of the bin is a great organic drain cleaner that controls smells and prevents algae build-up.  You can also dilute it for use as plant feed, but it looked like the plants would have to go hungry. My dad has always had a thing about blocked drains. I think it’s a man thing. Using the bokashi drain cleaner might save them a small fortune on whatever gunk he normally chucks down the plughole, and it wouldn’t be a bad thing for the water system too.

I gave them the bokashi bin and left them to it. Would they become bokashi fans or might it be too much change too soon?

At first Mum argued that there was no space on the kitchen worktop (what with her soup maker, bread maker, food processor etc) for the bokashi bucket so it was given a home on the patio table outside. After a few weeks, however, she did rearrange her worktop space to accommodate the bokashi bin and the sky didn’t fall in.

No blocked drains

Dad expressed disappointment that he wasn’t getting the promised bokashi drain cleaner. I explained it was quite normal to go a week at first without liquid while the process got going. Then he forgot to check for a few days and ended up with half a jugful of the stuff. He was highly delighted. I could tell no drains were going to get the chance to get blocked around these parts.

Bokashi ‘tea’ drain cleaner

My parents reported that after a few early instances of forgetting they had a new food waste bin, they quickly got the bokashi habit. It was now unthinkable for them to throw food waste in the normal kitchen bin, as they had done for the past 80 years.

We have had our bokashi bins for a while, but it was only when I was transporting my parents’ bins back and forth in my car that I came to appreciate how portable they are.  The cube-type shape makes them sturdy and the three locking clips mean they don’t spill. And as for the effectiveness of fermented bokashi mixture as a compost accelerator – wow, our compost bins love it!

Bokashi convert

Mum is now a complete bokashi convert. She says she feels ‘empowered’ by being useful. It’s been six months now and I can tell there’s no turning back.

‘We all have to do something about the climate crisis,’ she says, ‘and this isn’t a lot to ask, especially when you consider the upsides.’

All that remained was to take a photo using Mum as a model for this blog, showing ‘People in their Eighties getting the Bokashi bug’.

But when I turned up to take her photo, Mum had just been to the dentist’s and was looking very elegantly groomed and made-up – and not a day over 60.

I was dismayed. ‘You’re going to ruin my photo, you don’t look old.’

‘Really?’ she said, delighted. ‘You’d better use your dad then.’

Julie

Man emptying food into a bokashi bin

Dad does his bit – using a bokashi bin

Spare Parts