When I was at the Masters Conference at Garden Organic I was very interested to see a new ( to me) design of hot composting bin. Tony Callaghan was showing a new product - the HotBin. HotBin are made in the UK and Tony built his first prototype out of an old wheelie bin in his garden by going back to the basics of industrial composting engineering.
According to the HotBin website,
The HotBin is a simple design to help maximise what nature does by bringing together the right conditions to make hot composting easier. It is the bacteria decomposing the waste that generates the heat and the HotBin aims to keep them happy so you can enjoy fast successful composting. It does this by providing effective aeration between the bottom air inlet plate and the air outlet rotating valve, removing excess water through the valve as steam and allowing you to control the rate of heat loss.I have been interested in this compost bin design for some months, ever since it was mentioned by Garden Organic in a Master Composters newsletter. I was also very impressed by the design when looking at it on display and when Tony from HotBin offered me one to try out, of course I said yes (as I said in my Hungry Bin post, I never pass up the chance to experience something new involving composting and/or worms)
So when the courier arrived on Thursday with my new HotBin I was very pleased and couldn't wait to get the system set up. Fortunately we had a dry and sunny day on Thursday so I was able to take lots of photos as well
The HotBin is a very well insulated black box with a lid, it is about the size of a wheelie bin and according to the manufacturer is made of expanded polypropylene and when empty weighs about 3 Kg.
It comes with a built in temperature gauge on the close fitting lid ( for measuring the heat at the top of the bin), comprehensive instructions, a longer probe thermometer for measuring the heat in the working compost material, a "raking stick" a bag of bulking agent (composted wood chips) and a "winter kick start heater" hot water bottle (empty plastic bottle which you can fill with hot water)
I sited the HotBin what is rapidly becoming the "test" area, behind the barn- so I can feed it regularly and monitor the results.
What happens inside the HotBin is hot composting –dominated by bacteria – and ‘happy’ bacteria deliver fast successful composting. To keep the bacteria happy we need to provide the correct balance of HEAT, FOOD, OXYGEN and WATER
As the HotBin "Getting to 60 C " FAQ says
Don’t worry, you do not need to understand all the science to get the best out of your HOTBIN. The HOTBIN is designed to help maximise what nature does and brings together the right conditions to make hot composting easy. All you need to do is check a few simple settings, add the minimum amount and good mix of waste and you should soon be hot composting. The common barrier to achieving the best performance of a HOTBIN is that the mix and volume of waste is not quite right. However, if your HOTBIN is hotter than ambient temperature it will still be working faster than a traditional compost bin.
The instructions for set up are an easy to read flowchart layout and say.
You may have enough traditional composting material readily available to get going straightaway; if so put it all into the HOTBIN, the more the merrier.I obviously had enough traditional composting material available to more than half fill the HotBin, so got it going straight away. I used a mixture of week old material from an existing compost bin, fresh weeds, cut nettles, hay and guinea pig droppings and paper scraps.
You may not have enough traditional composting material; be patient and build up you base layer when material becomes available. The temperature in your HOTBIN will build up more slowly until you have enough waste in your base layer.
Remember you can add kitchen peelings to the base layer at anytime.
A good base layer will also have easy to digest material that has been chopped up < 4cm to help the bacteria generate heat more quickly. Items like grass and chicken poop or pellets really help generate heat faster.
I did not add any cooked food waste at this point as I did not have any, although I could have done so.
After 24 hours it had all slumped.
The ambient temperature was 18 Celsius when I filled the bin mid afternoon on a sunny but cool day. After less than an hour the top temperature gauge read 40 Celsius ( reading the air temperature at the top of the HotBin) and the top layer of material inside the HotBin was at 25 Celsius.
After 24 hours the top layer of material was at 40 Celsius and the lid thermometer read 50 Celsius with an ambient temperature of 20 Celsius.
After a couple of days, assuming I have followed the instructions correctly, I should expect to see a reading of 40 - 60 Celsius.
It was very easy to load the HotBin and so far I am impressed with the ease of use. I am also VERY impressed with the comprehensive and user friendly information on the HotBin website - especially the FAQ pages, which are full of all sorts of useful information about composting.
Let's see what the next few weeks bring!