Sunday, May 12, 2013

HotBin Composting

The Hotbin
I've just finished reading Jane Perrone's post on her experience with her HotBin and it reminded me I have been thinking of writing about my own experiences for a while, especially now that I've had it over 12 months so have seen it perform in all seasons.
Like Jane I was excited to take delivery because it meant I could compost all the things my wormery's and standard compost heaps couldn't, namely meat and cooked foods without the need for a Bokashi bin in the kitchen and the chance of it leaking and stinking the house out. Promised temperatures of 60C mean that even the problem of dogs mess can be eradicated because after half an hour or so at that temperature nothing nasty survives and it just becomes good old fashioned compost, saving me an awful lot of hassle (it sure beats bagging it in a plastic bag and putting straight into landfill).
Jane mentions that the bin is ugly but I disagree: It is a solidly built black polystyrene bin that slots in nicely down the side of the house in between my water butt and wormery's. I would even go as far as saying it is quite stylish looking, but you do have to bear in mind that I'm a bit strange when it comes to my composting set-up (touching on the fanatical when it comes to all things compost, even going as far as collecting banana skins and teabags from people at work and bringing them home to compost rather than let them go in landfill) ...
This is just after arriving and, untidy early Spring garden aside, I think it fits in quite neatly. When not over wintering in the greenhouse the wormery's live next to it so kitchen waste can easily be added rather than traipsing across to the lawn to the compost bins.
So how have things gone in the last 12 months?
First few months and emptying
I found it easy to get going and the compost-geek really kicks in when seeing the thermometer reading 60C and knowing that that means you are composting your waste at 32 times that of a normal compost bin (meaning usable compost in approximately 3 months!). However, Jane is right that it is a pig to empty. You remove the hatch and start forking out the finished compost only to find that the stuff above falls in its place before you get to the back, meaning not only is unfinished compost mixing with the good stuff but the compacted compost at the back stays there.
The "finished" compost is generally not the compost we are used to and will need ageing if it is going to be used as anything other than a rough mulch. You can either add it to a normal compost heap/bin for aging or add it to your wormery where the worms will go mad for it and turn it into even more beneficial vermicompost (more of a fertiliser than a compost). This is what I do now as I have 3 wormeries that were previously taking my kitchen waste but slowed down once the Hotbin arrived. They now take waste from the Hotbin every month or so and take another month or so to turn into vermicompsot for top dressing plants or adding round my vegetables as a mulch or feed.
Keeping the temperature up
The problem with emptying can cause problems with the air movement, which then results in the temperature dropping thereby slowing things down considerably. Once things get compacted the air vents in the bottom of the bin get blocked and the lack of air flow can cause the temperature to drop very quickly. I use a Compost mate that I bought from Wiggly Wigglers and currently costs £17.50 (worth every penny) for aerating the bin contents from above - you screw the tool into the compost and then pull out a plug of material creating a chimney that keeps the air flow working nicely (and the compost hot). However this can cause the newer stuff to fall deeper into the bin which means slightly longer before you can remove it.
In the summer keeping the bin hot is reasonably easy because you can add grass cuttings, though add too much and you get leachate leaking out of the bottom that attracts flies resulting in maggots and that silage-type pong oh so loved by ones wife (NOT!).
In the winter months however things are trickier and the bin maintenance becomes a weekly chore. I have found that adding LOTS of shredded paper helps in much the same way as it helps in a wormery; it keeps the air flow possible, dries out soggy compost (that can also restrict the airflow)and also keeps the temperature up as it composts quite quickly. I also add pelleted chicken manure to help keep the temperature up. So, the recipe is for each caddy of kitchen waste I add a handful of bark (supplied with the bin and also used for aerating the compost), a few handfuls of shredded paper and a cup full of chicken manure pellets. This keeps things working nicely as well as improve the quality of the finished product.
Much as I wouldn't swap it - when working well it works very well - and I'm turning kitchen waste round quickly for my plants at home and the allotment I don't think it is the single answer to all things compost. Much like my old composting set-up I think you need more than one bin, and at £149 that's unlikely because they are not what you would call cheap. With a second bin you would be able to have it composting nice and hot until it's full and then move onto the second bin. By the time the second was full the first should be done enough to be emptied completely and started again, thereby avoiding the emptying issues that make it so hard (and smelly) to use.
For more information and help Hotbin have a great Frequently asked questions section on their web site and are very good at answering queries both on Twitter and Facebook.


Anonymous said...

Glad to hear the HotBin worked out for you ... I guess we just have to agree to disagree on the HotBin's looks but I think your success depends on how much you want to put into it ... I am a bit of a lazy composter! The Wiggly Wigglers device sounds great - I'll have to look at that ...

tony.callaghan said...

Hi Simon
Many thanks for the review. As times goes by, different users are finding their own methods and tips. You may find some or all of these useful:

Emptying - we are find it falls in only about 1 in 4 times. I do not think there is a 'secret! The wet waste sticks and hold, drier waste falls. We have found only grabbing the central core, not trying to get it out of the corners not only makes it faster, but the "arch" helps support the waste above. Let us know if it works for you.

Stirring – we are not finding it necessary to stir. This stop/start temperature is indicating aeration is failing. This is most commonly due to a lack of bulking agent. It is critical – especially with soft, wet food waste. You can find more on the website at the FAQ post “wet waste” . Look forward to maybe discussing your recipe off line – but your winter recipe does look spot on, so maybe it just needs a bit more bulking agent in summer. bottom-of-the-hotbin-the-air-inlet-is-this-ok.aspx

Grass – you should never get the silage pong with grass - your grass has gone anaerobic. This is a sure sign you need to add some bulking agent and paper with the grass. Have a look at the grass recipe – I am confident you will get no stench and no leachate if you follow it.

Finished Compost – we wrote a long blog post on the topic that compost looks can be deceptive. IMHO the single most important active/beneficial part of compost is the humeric substance content. We value your feedback on this post and any tests you do on your composts.

simon sherlock said...

Thanks Tony, I certainly didn't add enough bulking agent last summer as the temperatures were looking after themselves (lack of bulking agent being the reason for the leachate). I have been adding it religiously since the Autumn and will continue to do so and will report back on how things progress throughout the summer.
I have taken your advice on emptying this morning - some fell down but not as much as on previous attempts. At least now the air holes are unblocked (for now at least). I also added some more grass, bulking agent, kitchen waste and shredded paper so will monitor the temperature over the next week (it is currently under 30C, probably due to the lack of air flow because of the compacted stuff I have now removed).
The stuff I have taken out is reasonable though with some uncomposted material still in it so I have dug holes in the borders and buried it, rather than use as a mulch. It will do wonders there when the bedding plants go in.
Thanks also for the links - I have used the FAQ a few times over the last 12 months but only really when I have had issues. I will keep checking back more regularly.

Donal Finn said...

I am glad that you are using Shredded papers in a good way. It is good to process the wasted papers in this way. Sometimes it becomes necessary to destroy the paper in that case one should avoid the burning process. Recently I have bought a new shredder online it is really good in efficiency and so economical in rates. If you are also looking for a good shredder then you can visit below address-

Ravs said...

Thanks for a great article. I've had my hotbin for over a year and have also had problems with emptying it. I've had unsatisfactory results with kitchen waste - meat on the bone had not decomposed after 6 months. I had a real problem with lechate and used a lot of bulking agent - dried woodchips and corrogated cardboard to help aeration and to absorb moisture. I believe that what might have happened is that the material at the bottom started to get really compacted so the airflow stopped in the bottom of the bin.

simon sherlock said...

Thanks Ravs, following Tony's advice above has made a big difference to the amount of leachate. My new routine is a layer of shredded paper, a layer of grass, food waste from the caddy and then another layer of paper with some bulking agent. Temperatures have been 60C or just under for a couple of months now, though the weather is obviously helping at the moment. Adding such a large amount of paper is obviously helping with the leachate situation as, compared to last summer, it is almost non-existent.

Jean C said...

I started Bokashi composting this spring, (using compostable bags rather than a Bokashi bin as the bins are so expensive - see Jenny's Swedish Bokashi blog) and found that if I bung these in my Hotbin and spread the contents round, the Hotbin heats to 60 degrees within hours - much better than the hot water bottle. The contents also break down very quickly - no meat left at all , but a few bones left in the finished compost. I know Tony says that Bokashi is not necessary with a Hotbin, but it means I don't have to go outside when it's cold and can put all the potato peelings, banana skins (not from workmates!) apple cores etc in one place and keep them without them smelling - so worth the cost of the Bokashi bran. I also have a worm bin, and they love Bokashi too. I agree that getting finished compost is a fiddle - how do you get it all from the back of the bin? Otherwise, I've been really pleased with the Hotbin plus Boakshi - the bin eats up all my garden and food waste, so I do not have to spend £40 a year paying the council to take garden waste away - and don't pay for compost or fertiliser. The Hotbin is really easy to keep tidy as you don't need to turn it - which is why I have given up beehive composting.

simon sherlock said...

Jean, thanks for your comments. I have never added Bokashi because after 2 weeks fermenting ion the bucket I found it was pretty much done, so just added it either to a normal compost bin or straight into the borders/vegetable patch. I'm also very wary of adding to the worm bin as I managed to poison a 12 year old wormery and mass worm death is not pleasant (on the nose or by the fact you have to start again).

Are you adding your Bokashi to the Hotbin as soon as your bag is full i.e. before it has started to ferment? If you are I think that could be a plan for me as well because the addition of all those micro-organisms could help improve the quality of the compost yet further and, as you point out, save you having to go outside on those cold and wet Winter days...

Jean C said...

I leave the bag for 2 weeks to ferment and then bung it in the Hotbin, as I don't have a 'normal' composting bin. I cut through the bag so the contents can mix with what is in the bin already. Temperature shoots up to 60degrees within hours - great when you don't have grass cuttings when it's cold. Bokashi contents break down very quickly indeed and all meat etc just breaks doen. I use lots of dry stuff in the Bokashi- shredded paper, used kitchen towel, newspaper so it doesn't get too wet, as I Bokashi in a bag. However, these 'composts or' bags take ages to break down - but allow me to follow the process of the Bokashi through to hot bin.
Would be interesting to see what unfermented Bokashi does....

Unknown said...

Hi Simon
I am looking at Bokashi composting and am wondering two things:
- can you leave the Bokashi bin outside even if temperatures are cold (we would have a small caddy in the kitchen and empty it daily into the Bokashi bin)
- if we lined the kitchen caddy with compostable bags, would these be fine to go into the Bokashi bin?
Thanks very much for any advice!

simon sherlock said...

Hi Beatrice, I have had no problems with Bokashi working outside but it will be slower which is why I kept mine inside until full and then occasionally put them out (though usually during the summer months). During the winter I guess you would just have to try it and see how you get on. If you were then adding it to the Hotbin it would break down soon enough no matter what so it's certainly worth a try...

As for the compostable bags I have no personal experience but Jean, above, has success with them so again it might be worth a try. At 60C the compostable bags *should* break down very quickly but be careful they don't restrict airflow in the meantime as that will have a negative effect on the temperature in the bin and could slow things down somewhat.

Please report back with how you get on as we're all learning new techniques and it's fascinating for me to hear what people are doing and their levels of success.

Chris Stevens said...


I bought a seconhand bin off Gumtree back in August and initially had problems with getting a good internal and lid temperature. In the end i read some comments on the Hotbin forum where people had removed the lid filter bag. This basically gets soaking wet from compost steam and eventually stops airflow. Once removed the temperatures increased with the lid temperature rising to a constant 50c and internal to 60c.

Hope this helps people with slow bins.


Karen Tait-Lane said...

I was doing well and got my hotbin up to 70 degrees within 2 days of setting it up however I have now had 2 incidents of the lid blowing open overnight and all the heat being lost. Surprising given i firmly push the lid closed and there is no obvious leverage for the wind other than the top vent. Really frustrating and have to take the lid and hope all is not lost...

Karen Tait-Lane said...

*tape the lid

Simon Sherlock said...

Wow Karen, I've never had that happen as the lid is quite heavy and sits well (generally). Could you add a house brick or two to weigh it down? Be easier than applying tape regularly I suspect.