How the Ridan Composter works

A diagram explaining how the Ridan Composter works


  1. Food waste, green waste and wood chip is added through the lid at the top. When the lid is closed it controls air flow into the composting machine and allows steam to escape back out. This process also removes excess water.
  2. The handle is attached to a series of gears to make turning easy. The gears, in turn operate a series of paddles which mixes and aerates the mixture.
  3. A combination of nitrogen (food waste), carbon (wood), oxygen and naturally occurring microbes all work together to convert the mixture into compost.
  4. The energy generated creates heat which can reach 60c, even through winter months. The heat turns excess water into steam which is released through the lid.
  5. The mixture is continuously pushed through the machine until it emerges as compost at the outlet where it is collected in a bucket. The final mixture still requires a couple of months to mature before being ready to use. The outlet also allows air flow in and out of the composting machine.


Working with nature

Composting is a natural process which will happen as long as the key ingredients of Carbon, Nitrogen, Air and Water are present.  For composting to take place naturally, the conditions have to be just right. It is not always possible to recreate those conditions manually, which is where the Ridan composting machine comes in as it makes it easy to create the right conditions.

The Ridan food waste composter uses natural ingredients and processes to create a warm environment in which food waste (nitrogen) and wood (carbon), can mix with air and water. Unlike other composters, all this happens without the need for electricity, making your Ridan cheap and easy to use.

Heat is created when micro-organisms, (including bacteria and fungi) break down the organic matter, food waste and wood. The heat attracts even more hyper active microbes, which make the composting process quick and efficient. This creates the perfect composting conditions.

Simply add equal amounts of food waste (nitrogen) and brown waste such as wood (carbon), then turn the handle a few times to mix and aerate……..that’s it!

What can be added to the Ridan Composter?

The Ridan composting system can compost all food waste and wood. Food waste includes meat, fish, dairy and eggs whether cooked or raw. You can also add green waste from the garden, so long as there is an equal amount of nitrogen and carbon.

Wood – Carbon Rich

  • Wood chips
  • Sawdust
  • Wood Pellets
  • Wood Shavings

Any of the above can be used bearing in mind the following points.

  • Chip, sawdust and shavings are waste products so can often be sourced locally free of charge from tree surgeons, sawmills or carpenters.
  • Keep it dry, store it close to the Ridan and under cover.
  • Wood Pellets, Sawdust and shavings break down quickly making great compost, larger wood chips take longer to break down making more of a mulch.
  • Wood Pellets work fantastically, you can order online and they will be delivered to your door, they come in convenient watertight bags and you only need to use 1/6th of the amount, however there is a small cost that equates to between £2 and £4 per week, so if you can’t find free carbon, wood pellets are still an excellent option.[/one_half]

Food – Nitrogen Rich

  • Dairy, cheese, butter, eggs.
  • Fruit and Veg (including skins)
  • Meat (raw and cooked)
  • Fish (raw and cooked)
  • Bread
  • Salads
  • Pasta, Rice
  • Manure (including rabbit & guinea pig droppings)
  • Plate scrapings, anything edible.

All raw and cooked food waste can be composted in a Ridan, but remember to drain off excess fluids, cut up big chunks and avoid all but small bones. Fruit, veg, greens and prep compost most easily, however starches, meats and dough take longer to digest, much like our own digestive systems, so a mixture of both types of foods is essential.

Dead leaves, straw, paper, cardboard and tissue can be composted by layering them into the Maturation Box, between the compost as it is loaded, this works better than adding them to the Ridan, they cannot replace the wood.

Daily use

diagram showing the daily operation of the Ridan composter

  1. Prepare your food waste by cutting up large chunks and draining as much excess liquid as possible.
  2. Open the lid and add your food waste, but ensure you add an equal amount of wood chip too.
  3. Check you have an empty bucket at the outlet as mixture will start to come out when you turn the handle
  4. Now you can turn the handle. Give it about 5 full turns per day.
  5. Any mixture that is expelled from the outlet can now be added to the maturation bin.

Maximum throughput

The maximum throughput refers to the maximum amount (in litres) of food waste that can be processed in your Ridan composter. This amount does not include the carbon (wood) materials. The figure quoted for the maximum throughout is the absolute maximum but the optimal amount is significantly less.

You do not have to fill the composter to the maximum or optimal amount. Small amounts can also be composted, just as long as the balance of food waste and wood are maintained.

Using Your Compost

Depending upon what sort of food is being composted it may be ready to spread straight onto the garden. However, it is usually best to mature the compost for a few weeks in a Ridan Maturation Box. Here the composting process will continue to break the products down even further.

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