Electric Composters – An Eco Win or Unnecessary Appliance?

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Robert Pavlis

I became aware of the first electric composter a couple of years ago and now there are at least a dozen brands on the market. They are promoted as an eco-friendly way to deal with food scraps. Just put your waste in the device and it will compost the material in a few hours. The material is reduced in volume by 90% and is a perfect fertilizer for your houseplants and garden.

The first one I saw was a larger floor model that required the addition of coir, and some models suggest the addition of microbes to help with the composting process. Newer models are smaller in size and don’t require the addition of coir or microbes.

Right from the moment that I saw the first unit, I questioned the “composting” aspect. How can they compost so quickly when composting is a very slow process? My myth busting antennae went up.

Electric Composters - An Eco Win or Unnecessary Appliance?
Electric Composters – An Eco Win or Unnecessary Appliance? Showing Nagual composter.

What is an Electronic Composter?

You may not have heard the term before. This category of products is still trying to find its footing and final marketing labels. They are also called food recyclers, food processors, or food digestors. They all operate in a similar manor, with the exception of the above mentioned coir and microbes. Food scraps are placed in a bucket, the unit is closed and turned on. An automated cycle dries the material and “grinds” it. The time needed for this depends on how much you put in and how wet it is, but most units take 3 to 5 hours.

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At the end of the process you have something that is dry but still kind of resembles the food you put in. Some items turn into brown powder while others stay quite chunky and fibrous.

There is a bit of odor, but it is not unpleasant. Some units have charcoal filters that reduce the odor while it is exhausting the water vapor.

The buckets are quite small. The one I tried, had a 2 liter capacity (0.5 gal), but that’s a bit of an exaggeration since you can’t fill it to the top and most of the space is air. We produce very little kitchen waste, mostly orange rinds, banana peels, apple cores, some potato peelings and a couple of egg shells and we can fill it in 2-3 days.

Do Electronic Composters, Compost?

The answer is clear – NO!

Almost all the manufacturers of these units claim they make compost because that is a popular, eco-friendly way to handle food scraps. Any company making this claim is using false advertising to sell their product.

I found this comment, “The machine runs for 5-6 hours – yes, it’s a while, but you’re speeding up science, so let’s have some patience! ” The only science it is speeding up is the drying of food.

I contacted several manufacturers and asked them for proof that they compost. None had any. To be honest they didn’t really understand what composting is. The exception to the rule is the Vitamix FoodCycler who are more ethical. They made it clear they “don’t compost”. They reduce the volume of food waste and hope that their product diverts it from landfill.

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Vitamix FoodCycler dehydrated food waste byproduct
Vitamix FoodCycler dehydrated food waste byproduct

FoodCycler also provided me with some analytical data for their end product that showed a total nitrogen level of 2.9% and a nitrate level of 0.005%. During composting, organic forms of nitrogen are converted to inorganic forms of nitrogen, mainly nitrate. These numbers confirm that composting has not yet started.

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Running Temperature

These machines claim to run hot. The Nagual runs at 120 C ( 248 F) or is it 126 C – both values are given. When I open it during a process, it is not that hot, but it does have to be over 100 C to drive off the moisture. A hot compost pile is limited to 66 C (150 F) so that the microbes are not killed off. The steam plus high temperature will sterilize the food scraps.

Another reason why there is no composting!

Do Electronic Composters, Grind?

Many of the products claim to “grind” the food as it’s heated. The blades in the unit are not sharp nor is the space between the blades and the fixed bar, small enough to grind food. They rotate once per minute and at best this can be called agitation or mixing. This also becomes evident when you look at the results. The material is not finely ground and contains a lot of larger pieces. Don’t believe some of the picture shown by the manufacturers. 

Dehydrated kitchen waste: claimed by marketing (left side) vs actual found in my tests (right side)
Dehydrated kitchen waste: claimed by marketing (left side) vs actual found in my tests (right side)

Do Electronic Composters Produce Fertilizer?

The end product from the FoodCycler had an NPK of 2.9-0.2-0.6 (made from food scraps) but this depends a lot on the material being processed. It has a higher level of nitrogen compared to P and K. It also had sodium levels between 0.2 and 0.5%. Processed food and canned food tends to add high levels of sodium, which can be toxic to plants.

The NPK from an industrial electronic composter at the Leiden University Medical Centre kitchen was 2.7-0.7-1.0. Sodium levels were 1% and the pH was 4.3.

Industrial electronic composter from Oklin
Industrial electronic composter from Oklin

Electronic composters produce dry food scraps. Until this material starts to decompose, most of the nutrients are not available for plants. Most manufactures of these products show how easy it is to take the dry material from their unit and apply it to potted plants, but I would not do that.

A study done by Vitamix had this to say, “We recommend delaying planting following application of the dehydrated food waste byproduct to soils to allow sufficient time for decomposition to take place, in order to ensure that germination is not inhibited by the decomposition.”

The term, “dehydrated food waste byproduct” seems like a good description of the material produced by these units. I would not call it fertilizer, but gardeners use the term in a very general way to refer to anything that releases plant nutrients. Is an apple fertilizer? If you believe it is, than a dried apple is also fertilizer.

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Eco-benefits of Electronic Composters

What can you do with food scraps?

You can compost them yourself and that is probably the best option. This can be either an outdoor compost system, vermicomposting, or even bokashi composting.

Another option is to send it to a municipal composting facility. This is also a good option especially if you don’t have a garden.

You can send it to landfill (ie throw it in the regular garbage). This is the worst option because organic matter in landfill can’t decompose anaerobically, and therefore produces methane gas, which is 25 times worse than CO2 for global warming.

Use an electronic composter. This is only eco-friendly if you don’t send the food waste to landfill because reducing its volume by drying does not reduce the amount of methane it produces in landfill.

Weight and Volume Reduction

The marketing material for this product makes a big deal about reducing weight and volume by 90%. My testing has shown that volume reduction is more like 75%, but that is not really the important point.

The food waste is reduced by weight and volume due to a loss of water. All of the organic matter that was there at the beginning, is still there at the end of the process.

In landfill, a whole apples produces just as much methane as a completely dried apple. Granted, a dried apples takes up less space for shipping to landfill.

The reduction in weight and volume is only a benefit if you are going to store the material. It does NOT help the environment, as is suggested by marketing material for these devices.

Personal Experience

A new company in this market space, Nagualep, sent me an electric composter for evaluation on my YouTube channel. This system seems to be well built, works quite well and is quiet. You could easily work beside it and not find it distracting. It lists for $700 but is available for $300 as an introduction to the North American market and has been selling well in Asia. It takes about 3.5 hours for a batch.

The manufacturer claims that “it is 100 times faster than traditional composting”. Well ….. yes it is much faster, but it does not compost anything.

How Should Dehydrated Food Waste Be Used?

It can be composted, added to a vermicompost bin, used as a mulch in the garden or added directly to soil. If you burry it, don’t plant seeds or seedlings above it right away. Allow a month or two for the composting to start.

I would not mix it into the soil used for potted plants in case the material robs nitrogen from the soil during composting. Using it as a mulch on top of the pots should be all right.

Another good way to use the material is in a Soil Factory, which I have discussed for Bokashi.

Are Electronic Composters Eco-friendly?

These units use about 1 kWh per cycle so the energy use is fairly small, but it is another product that needs hydro.

The unit also has to be made, packaged, and shipped around – that is never eco-friendly. Several of the brands suggest regular (every 6 months) replacement of expensive charcoal filters – more eco-waste.

To answer the eco-friendly question we have to compare options. We all make food waste, so what is the most eco-friendly option for dealing with it.

To be quite honest the best thing you can do is create less waste. I have looked at data that shows people create a huge amount of food waste. My wife and I almost never throw out left overs. Fruit and vegetables rarely go bad because we don’t buy an excess amount. Before you do anything else, produce less waste.

The second best thing you can do is compost, even if this means sending it to a municipal composting facility.

Is an electronic composter eco-friendly?

Here are my issues with it.

  1. It is expensive to buy.
  2. It takes up way too much room on a counter top.
  3. Making it, running it and disposing of it at the end of its life are not very eco-friendly.
  4. What are you going to do with the dehydrated food waste? If it is sent to landfill you have accomplished nothing for the environment. In fact, you have made it worse. If you add it to the garden, compost bin, or send it for municipal composting – you could have done that without an electronic composter.

I can think of only one scenario where an electronic composter is eco-friendly. If you don’t compost and you don’t have access to municipal composting, then an electronic composter makes sense provided you collect the dehydrated waste and give it to someone who can use it. Even spreading it in the woods is better than sending it to landfill, but that really should not be done.

This device may also be appealing to people who live in cold climates where they can’t compost in winter. You can use it in winter to dry the food scraps, store them dry and then compost them in summer. A more eco-friendly solution to this problem is a pail in the garage to collect the material in winter. Mine sits in an unheated sun room.

If I have missed an eco-friendly way to use the device, please describe it in the comments below.

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

61 thoughts on “Electric Composters – An Eco Win or Unnecessary Appliance?”

  1. NatureMill Plus XE
    Automatic Indoor Composter
    https://www.peoplepoweredmachines.com/naturemill/naturemill_plus.htm
    No longer in production

    I bought it in 2008 ish time frame, mine still works , it has a silicone heater strip glued to the stainless plate that can rotate to dump the finished product into a bin below. Before dumping, the cycle mixes the material periodically, every few hours, then after 72 hours I think it is it then signals the dump. The heat applied brings the material to no more than 120f, enough on cool days to present some vapor. The composter is sealed in Styrofoam to retain heat.
    It is far faster than my conventional manually rotated composter next to the garden. I use the electric one to create compost faster while the other is composting a much larger batch for a longer period of time.
    I tried using it inside but if you don’t manage what goes in properly despite the charcoal it smells to bad, so it is parked outside next to the patio.
    Also found that by adding wood pellets on occasion to the mix turns out some very good compost.

    Reply
  2. Had my nagual for about a year now. All the scraps processed in it are added to my compost. We have a small garden and our plastic compost bins fill up fast with garden prunings/weeds/grass clippings. It’s nice to add food scraps in a way that is less attractive to pests and takes up less space (also composts faster due to surface area increase). It’s not magic and it wasn’t cheap but it does a job well

    Reply
  3. Hi! Thanks for the thorough analysis! I live in New York City and our fridges are terribly small because our homes are small. It is also not practical to take my food waste out to public compost bins every other day (think eating melons…). Obviously, we don’t have a backyard where we can compost our own food waste. The compost machine allows me to store my food waste for a few months in simple plastic cereal boxes and take them out to compost bin all at once. I absolutely love the convenience and certainly I ended up sending much more food waste to compost collection bins provided by the city. Hope this is helpful.

    Reply
  4. Thanks! I was on the fence. But after reading your article, you convinced me I do need one. I am moving into a house in the city with a not-so-great HOA that doesn’t allow compost bins in yards. This will resolve my food waste problems. “Composted” or “not,” better than nothing.

    Reply
  5. I’d agree that compostable bags aren’t necessarily amazing in say NA, but the EEA has far better regulations on that

    Perhaps it’s why they can’t be sold as composters over here but food recyclers

    Reply

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