Tumbler versus HOTBIN
Tumbler compost bin versus HOTBIN with no turning
If you have landed on this page, you are probably trying to decide whether to buy a tumbler compost bin or the HOTBIN. We offer you a quick ‘expert’ recommendation and a more detailed list of items so you can evaluate the type of compost bin for yourself. Alternatively jump to over and read what HOTBIN customers say
Our expert recommendation: As soon as you set a goal to compost all food waste (including meat, leftovers, bread, pasta, etc), and you want to compost all year round (through winter), with no vermin, flies or odour, then you need to opt for a specialist ‘hot composting bin’. Many tumblers are not capable of hot composting. If you hot compost and use a bulking agent there is no need to turn your compost.
Decide for yourself (list of things you should review):
To establish if a product is “better” you need to take a step back and ask – ‘What am I trying to achieve?’
There are two sets of features to look at. The first group looks at whether you want to hot or cold compost, and the second group look at how easy the compost bin is to use.
Group 1 – Hot or cold composting?
Do you want to:
- Compost ALL food waste from a typical domestic home
- Compost all year round (i.e. through winter)
- Compost faster typically less than three months
- Compost difficult garden wastes (e.g. weed seeds, couch grass, etc.)
- Compost without rats, flies or odour
- Compost without turning (fork over the heap)
Vendors will try and persuade you their bin will do ‘a lot’ and you can ‘control things’. To a degree this is true – but there is a huge performance gap between a bin designed to hot compost and a tumbler that holds waste while it cold composts.
- Feed it the right mix of chopped up waste
- Retain heat – ie insulate it by using specialist insulating materials
- Aerate – harness the science of buoyant airflow to get air to each bacterium at microscopic level
- Control water – remove excess water from the mix
- Enclose the waste, remove odours and control vermin and flies
The items are connected – get all five right and it is a virtuous circle, get one wrong and it can quickly form a vicious circle, spiralling downwards out of control.
Feed it: Some materials compost faster than others. Feeding chopped up, ‘easy to digest’ waste allows fast digest and hence fast heat release.
Retain heat through Insulation:
All things compost faster as a function of temperature (read about the Q10 equation here)
. No compost heap will compost faster unless
it retains heat. Plastics are very poor heat insulators – do not get fooled by names like ‘thermo’ and a few extra mm of plastic. You need a top quality, waterproof insulated material/ Just like your loft insulation ask for U or R value rating! Most tumblers have no insulation of any significance so they do not retain heat. The HOTBIN is designed to control both conductive heat loss (via insulated walls) and convective heat loss (hot air flow). If your goal is to hot compost; walk away from non-insulated bins. If you goal is to compost typical amounts (2-5Kgs) of food waste through winter, check the insulation works – look for user endorsements offering time & temperature graphs using on known amounts of waste (Kgs/week). We are NOT aware of any insulated tumbler guaranteeing winter hot composting of 2-5Kgs per week.
Aerate the waste:
You can hot compost without turning! The science (ref in T Huag, Compost Engineering) states air introduced via turning will last only a short time. If you have twiggy/woody material that maintains ‘free air space’ structure and a temperature gradient, it will aerate via buoyancy air flow. To learn more about the theory of “no turning” visit our buoyancy airflow and free air space faq
Plus you need to take into account spinning or turning a compost tumbler is not always easy.
100 litres = 50 Kgs, 200 = 100 Kgs.
Even with levers this can be hard and it places huge stresses on plastic and metal joints.
Control moisture: This is critical to the composting process. Kitchen scraps are wet, as is grass clippings need to be balanced with dry materials. Some tumbler models have drain holes in the drum, and also a collection chamber in the base to receive the “compost tea”.
Wet waste: Wet waste tends to rise and then slumps to bottom – it churns into a solid sludge- the last thing you need! Wet waste is the norm when composting all food waste. This is really easy to handle in the HOTBIN – you just add shredded paper and bulking agent to balance the system.
N.B. Leachate: most of the excess water is driven off as steam in hot composting. Some excess will drain down. Look for a bin/tumbler that has some form of leachate collection
Control Odour: All composting produces odour. Aerobic composting avoids anaerobe pungent putrid odour – but it has a cabbage odour. You need to filter odour and reduce the any possible chance of attracting flies and vermin. Check if your tumbler has any odour filter mechanism – the HOTBIN does!
Pest control: Do not get sucked in by statements like “compost tumblers are 100% pest proof since they are fully sealed”. We believe no domestic compost bin is rat proof. Rat experts will tell you they will eat through all plastics (be it 3, 15mm PE or 50 mm EPP as in the HOTBIN) if there is any gap. Understand vermin – what attracts them (odour, warm and quite nesting sites), then look for design that makes the bin highly rat resistant. If you bins has ANY open holes of 0.5cm or larger and odour you will have problems sooner or later. Always look for off the ground, and look for a filter that removes residual odour to a very low non-nuisance level.
Group 2 – Usability factors
What are the key items that make it easy to use;
- Loading and unloading
Assembly: Bit of a preference – we suggest you look for bins that come ready assembled or at least require very little self assembly. HOTBIN requires none.
Loading and unloading: Small loading and unloading hatches panels are fiddle and difficult to use – it is a big issue for some composter. Some tumblers are good – others are hopeless. The HOTBIN is OK.
Batch or continuous: You can fill the HOTBIN to the top and leave a batch to mature (batch) or more commonly, you keep filling at the top and take out the compost from the bottom without stopping (continuous). With most tumblers there is the issue of when to stop adding new materials so that the whole composter can “finish” and the compost can be removed. Dual chambers are better than single so you can swap compartments, otherwise you may be looking at two bins. (This is a bigger issue if your goal is compost food waste over winter as you cannot stop for 2 months.
Durability: Choose carefully! Tumblers tend to be more heavily constructed since they need to be strong enough to hold the full weight of the composting materials. This does not always work – many fail at the joints and stands. Inspect the supporting legs and the central axis connection – they should be built to last years of use (Check for customer’s reviews after years of use!). The HOTBIN has no moving parts – and only a door to take on and off.
Size & Capacity: Avoid thinking bigger is better. Hot composting is typically 10-30 times faster – so you need vastly less capacity. When hot composting, match the size to the amount of waste – it is harder to get a big tumbler hot with a small amount of waste – the laws of physics do not support small amounts of waste getting or staying hot in large empty bins!
Price or rather value for money:
- The HOTBIN = £120-150
- Non-insulated tumblers = £70-500
- Insulated tumblers = £170-£450
HOTBIN composting supply a compost bin. If you are wondering how and why we are open about offering the secrets of buying the right bin – well its straight forward – our product is excellent, the customer’s reviews say it is excellent, we have used robust composting science and engineering for the design and operation. We have confidence you will choose the right product.
Jump back to HOTBIN products page. Jump back to your shopping cart
How to compost grass lawn mowing
To get fast superb results when composting grass lawn mowings in the HOTBIN:
Add 40 parts grass with 20 parts shredded paper and 1 part wood chip (bulking agent)
Typically this is a medium sized lawn mower collection box (40 litres) with a full carrier bag of shredded paper (20 litres) and 4 hands full (one 2-litre measuring jug) of bulking agent.
If you want to view a photographic sequence of grass compost stages, you can jump to our post on steps / stages of grass composting.
Below we explain why this recipe works, why just adding large amounts of grass can be problematic and offer 6 different options for handling large volumes of grass cuttings
The problem often seen when composting grass is you end up with a black slimy layer that stops the compost heap working.
In a HOTBIN you should get brown mulch in 7 days
Grass is one of the quickest materials to compost. In the HOTBIN you can typically convert grass to mulch within 7 days. Grass is so quick to heat up to 60-70C, the HOTBIN team recommend it to help accelerate and increase temperature quickly.
BUT! You can end up with a black anaerobic slime
In traditional compost heaps, it is one of the most troublesome materials to compost. Grass often heats up for 2 days and produces a very distinctive whiff (ammonia/urine). After 2-days it then ‘collapses’ into a cold, wet, slimy black mass that smells horrible (anaerobic mush).
Funnily enough we don’t have a picture of this as if you do it correctly in a HOTBIN it shouldn’t happen!
Composting grass successfully requires a little bit of extra composting knowledge but the real secret is matching the amount of grass you generate with the time and effort you have available.
Why does grass turn into a slimy putrid mess?
The ‘black slime’ is due to anaerobic conditions, i.e. excess water and too little airflow. Grass (lawn mowing) has a high water content (>80%) and no lignin (i.e. no woody stalk). As grass starts to decompose, the plants cells break down and become soft; water is released. The grass collapses and forms a thick impervious layer and airflow decreases. This in turn means the water is trapped, the process slows and a vicious circle is created where water is not removed, all oxygen stops flowing and aerobic bacteria cease to release heat. The heap cools and anaerobic bacteria take over releasing obnoxious odour and resulting in a ‘black slime’.
The golden rules for successfully composting grass are:
- Remove excess water
- Keep the grass aerated
- Balance the mix to avoid ammonia odour
So how do we get rid of excess water, keep the waste aerated and avoid both ammonia and or anaerobic odour?
- To remove excess water
You need lots of heat, i.e. you need to be ‘HOT composting’
- To keep the grass aerated (i.e. get air/oxygen into the grass layer)
You need buoyant airflow which requires a temperature gradient and a structure with spaces and gaps so the air can flow up.
Unless you have the means to force airflow (e.g. a pump / blower), or you can constantly turn/tumble (yes we mean constantly), then you are reliant on “buoyant airflow via the chimney principle” – and this requires the grass to maintain a structure with small air spaces (ie not a thick wet slimy mass!).
To get a structure that stops grass collapsing into a slimy heap, you need to add what we refer to as a bulking agent (typically this is wood chip). The bits of wood chip act like ‘stacking blocks’ and the air flows around them. Simple but essential!
- To avoid ammonia odour
To prevent excess ammonia, you need to be adding a fast/easy to digest carbon material like shredded office paper or chopped up corrugated cardboard.
The odour is caused because grass has an excess of nitrogen which the bacteria are unable to use as fast as it is released. So it forms ammonia gas and evaporates away. You are most likely to notice this when composting and/or turning large quantities of 1-2 day old grass lawn mowing. After 3 days things slow down and the nitrogen is no longer in excess. Turning grass heaps does not prevent the odour – it enables the trapped gas to escape ‘all in one go’. (If you have done this job, you may well come back inside the house and realise your clothes smell of ammonia!).
The HOTBIN does have an odour filter in the lid that does remove ammonia odour. But, when you add a whole box of grass in one go without anything else, the filter gets temporarily overload for 2-3 days. To prevent the odour during the initial 2-3 days you need to balance the carbon/nitrogen ratio.
You achieve this by adding a dry high carbon waste. The key here is to add ‘easy to digest carbon’ such as corrugated cardboard or paper shredding. Woody items like sawdust, shavings, wood chips are high carbon – but they are not easy to digest, so will not balance the C/N during the critical 2-days of intense activity. Here is the challenge – you need a lot of dry carbon! A 40L grass box (a typical mower box), needs 20L of paper – that’s a whole carrier bag full. It also needs to be mixed with the grass. Not everyone wants to do this, especially after cutting the grass. Below we outline a few options about different methods you might want to follow.
Large amounts of grass waste need extra steps to compost quickly, without ammonia and without turning putrid. Is the extra effort worth it? We think so! Each year fertilising grass lawns consumes considerable inorganic fertiliser – adding the nutrients back via compost is environmentally better.
Below are six options/choices for composting grass. Often you can ‘mix ‘n’ match’ routines at different seasons and times of the year to cater for the varying grass volumes.
1) Small to medium lawns – add grass into your HOTBIN each week
The HOTBINn will easily compost grass from a small-medium lawn (approx 40 litres/week or 1 large grass box per week, filling about a quarter of the bin each time).
This will generate some odour that you may well notice for 2 days. If this bothers you, there are a couple of methods to solve this:
- add shredded paper or corrugated cardboard in ratio 2 parts grass to 1 part paper
- Only add half a box, then return 3 days later add the other half
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|40 litre (approx 20 Kg)
||Add 2 litre (a measuring jug) of bulking agent. Mix in well
||Add 20 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
2) Large lawn – use a dedicated HOTBIN for grass
If you have a large lawn and generate 3, 4 or more boxes each week, then you will need to consider a dedicated HOTBIN. It will cope with 2-4 boxes (about 60-80L) per week.
The same rules apply – but adding and mixing in large amounts of paper is intensive and requires a high degree of commitment – perhaps not what you want straight after cutting the lawn! Large lawns allow the HOTBIN to be located away from your seating area – so we suggest you save your effort of adding shredded paper to eliminate ammonia odour – just leave the HOTBIN down the garden and reap the benefit of fast compost without anaerobic slime.
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|80 litre (approx 40 Kg)
||Add 4 litre (a measuring jug) of bulking agent
||Leave remotely and accept ammonia for 1-2 daysAdd 40 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
3) Leave the cuttings to compost on the lawn
Many gardening sites now actively promote leaving grass cuttings on the lawn. Normally you use an adapted/special mower blade that chops the grass into very small pieces (2-5 mm) and thoroughly spreads them. The method is to weekly trim of top third of grass and spread this evenly so it composts quickly, adding nutrients back to soil, but not creating thatch. If you have the grass ‘trail line’ down side of mower, then this will rot into mulch that blocks light and growth and does create thatch. Please refer to manufacturer for correct mower blades/settings. If you walk regularly on your lawn – you may find bits get on your shoes and are walked back into the house!
4) Best of both worlds’
Add the first few cuts of the year which tend to be large (say 3-4 boxes) into your empty HOTBIN. The bin is full for a week or so, and then rapidly becomes half-empty allowing ongoing use with food. After the spring cut, leave grass cuttings on lawn. Occasionally (e.g. when cutting hedges) add the grass box back on the mower and collect grass to complement garden ‘browns’.
5) Transfer grass to Local Authority
This is unlikely to interest HOTBIN users, but it is possible to have grass collected at the kerbside and taken to the council recycling centre. We are strong believers in home composting and believe in the environmental benefits of saving fuel and transport.
6) Allocate a large, remote area of garden to build smelly grass mounds
The mounds will tend to be smelly and go anaerobic, but it is fast to empty and dump lots of grass. We had rave reviews on how fast and efficient the HOTBIN is with grass – so maybe you do not need this option anymore!
So in essence it is easy to compost grass in your HOTBIN but depending on the amount you need to consider which methodology is best for you.
How to Choose a Compost Bin
You can compost for nothing ( zero pounds / dollars) by piling your garden and food waste up in a corner. How do you decide whether to pay 20, 60, 185 or even 900 pounds (yes really!) for a compost bin? You ‘justify’ the cash by convincing yourself of the ‘value’. We show you how to do this by checking the composting features meet your needs at a price you can afford.
Sounds like hard work – why not just go online, look for a 5 star ratings and best price – job done.
Well you can do this. Compost bins like the HOTBIN have extensive customer reviews. BUT most online reviews go like this: “arrived (did not arrive) on time, it was easy (or hard) to set up. I will let you know how it works in 12-24 months – but few go back to add. So make sure you look for the really important five star rating – the bits that says: ‘it works it gives me great compost, it does what it says on the bin – it hot composts fast’.
We can summarise the process of how do choose the ‘right compost bin’ or the ‘best compost bin’ for you into seven steps:
Step 1 – WHY
Consider & define your composting objectives
Step 2 – WHERE
Review your available space and location for the compost bin
Step 3 – WHAT & WHEN
Review the seasonality, volumes and types of garden and food waste you produce
Step 4 – EFFORT
Consider how much time and effort you are willing to invest on composting
Step 5 – HOW
Consider which compost method (eg hot, cold, digesters, vermicompost) and which bin features are essential and which are nice to have (eg low odour, no rats, no flies, in/out waste list, sanitization)?
Step 6 – CHECK
Build a compost bin feature checklist
Step 7 – MATCH
Asses which compost will deliver the best price/performance
Before we go any further, let’s consider your time and effort to read this blog and research composting. Some may genuinely have the time available and interest in composting to fully research the topic – you should read the detailed steps below and take a look at these excel sheets we made to create your own evaluation.
The simple one:
The complicated one:
(We will load this on the website for you to download but if you are desperate for a copy get in touch)
Please share how you got on and what you decide!
The majority of readers looking to buy a new compost bin probably just want a ‘fast track’ to help them make a quick decision with a degree of confidence that they are choosing a compost bin that works. It’s not easy to fast track – there is no BSI standard, nor many user reviews of actual compost bin performance. If you are short on time, I suggest you skip the detail below and jump to the ‘reading between the lines section’ which has a few checks to help you gauge if the compost bin supplier has in depth expertise.
Step 1 – Consider your composting objectives:
- Do you want to make lots of rich/great compost for your garden that will improve its fertility and lessen/reduce your use of fertiliser and maybe even peat?
- Do you just want to keep the garden tidy?
- Do you want to make a more positive contribution to the environment by recycling all your food waste so your local council no longer has to collect and transport it to landfill or a central AD/IVC reprocessing plant?
- Are you just fed up with allocating more and more of your flower or vegetable patch to overflowing compost bins that never seem to do anything?
- What are your objectives on sustainability, organic gardening, good use of limited resources.
Step 2 – Review your available space and location for the compost bin:
- Some compost bins are limited in location (eg keep it in a sunny spot, or the opposite ‘keep it in the shade’, ‘only use on soil’, ‘do not use on clay soil’. You may have very little choice (eg it needs to go on the concrete by the garage). Your location may limit your compost bin choice.
- You might have a small garden and no space for a large compost bin, conversely you might have very large garden and taking 3 metre square for a traditional 3-bay New Zealand compost bin system might pose no issues.
- Do you want to the compost bin close to the kitchen so you can pop out easily in the rain to empty your food caddy?
Step 3 – Review the volume of garden and food waste you produce:
- Are you just going to compost seasonal garden waste (summer/autumn)?
- Do you want to compost grass cuttings (spring, summer, autumn)
- Do you want to compost food waste – produced all year round – ie compost through winter
- How much of each type of waste do you have? In my experience, very few garden composters or food waste recyclers accurately know how many litres (or Kgs) of waste they produce. Very few have any real desire to record and measure it either. Choosing the right compost bin size is also further complicated as compost bins can (given the right conditions to achieve ‘hot composting’) compost 32 times faster than a competitor bin that only facilitates ‘cold composting. So 20 litres of waste a week in one bin would rapidly break down within a week, but in another bin build up over time and need a 600 litre bin.
Step 4 – Consider if you want to ‘hot’ or ‘cold’ compost?
If you are unsure and want to learn more about ‘hot Vs cold’ follow the this link to Hot v Cold composting. The headline benefits of ‘hot’ composting over ‘cold’ composting are:
- Hot composting will destroy weed seeds – saving you time and effort in future
- Hot composting will destroy dangerous bacteria so you can compost all food waste
- Hot composting requires far less space to compost the same amount of waste
- Hot composting requires dramatically less time (eg 30 days Vs 360 days)
- Hot composting works all year round (cold heaps all but stop in winter, temperatures of 0-5C)
Step 5 – Consider how much time and effort you are willing to spend on composting:
This is hard – everyone tends to answer – ‘none / minimal’. The more a vendor knows this is critical to your choice, the more pressure to use the term ‘easy’ and the bigger the potential expectation gap and likely hood of user disappointment. There is always some effort (eg collecting food, turning, mixing, shredding). In our experience, things can be made very easy by habitually following simple method-steps. But investing the time to form habits can be challenging – especially at the start when people perceive the habits are taking more time not saving time.
So, now you have a clear picture of what you want. Next, how do you check and match the compost bin against your composting objectives?
Step 6 – Build a compost bin feature list:
Build a feature list, locate the top 10 commercial bins, score each feature, eliminate those compost bins that do not fit your needs to produce a short list; then weight/score the remaining compost bins to find the best match.
Step 7 – Asses which compost bin will deliver the best price/performance:
Rate (Score) the competence of each compost bin against each feature, ie establish the performance and derive and overall value for money score – the million dollar question!
Commercial Product managers do this kind of work as their day job – but it is likely very few composters, gardeners or food waste recyclers have the time or inclination to do this.
If you have both; follow this link to the ‘compost bin competitive evaluation sheet’. You will find 12 widely available compost bins types and brands professionally analysed. You can play around with the scores and weighting to see which you think is best.
Accepting the majority of readers will not want to do this; how do you ‘read between the lines’ and spot the vendor marketing hype (that’s the polite term!).
Reading between the lines:
- The obvious choice is to seek user recommendations. As part of our competitive research we scan websites for ratings and reviews of compost bins. Often they just state: the bin ‘arrived/did not arrive’ on time, it was ‘easy/hard’ to assemble, followed by ‘I’ll let you know how it composts’. There are only a few reviews where people state: it delivered great compost just like the vendor said in X days.
- Validate vendor promises… (eg compost in 7-days). Look for detailed scientific study from reputable independent organisation to support.
- Check vendor expertise – does their website offer real in-depth hands-on composting advice or does it just regurgitate the same old ‘in/out’ list that applies to ‘cold’ composting without offering explanation for how it differs for hot composting?
- Look for vendors with expertise in composting science & engineering. All composting (from the autumn leaf on the floor to an industrial scale IVC plant) obey the same laws of nature like cooling rates, rates/speed of biochemical reactions. Should you the consumer need to know about the science and engineering of composting? Of course not, but we believe your compost bin vendor does.
I said in the introduction, you can compost for nothing (£0s) by just piling stuff up in an open heap. To justify the cash outlay you have to generate ‘value’ and you do this by checking the compost bin features deliver against your composting objectives at a price you can afford. We hope the above tips combined with the tools in the links will help you create ‘value’ and help you decide which compost is right for you.
In my opinion, as soon as you set an objective like ‘compost all food waste with low odour and no rats or flies’ or ‘compost using an easy recipe’; ‘compost fast’; ‘compost year round’ then you need a specialist bin that offers great performance at an affordable price.