Sometimes it can be a bit of a struggle to get the HOTBIN up to 60°c. One of the most common issues is that the waste is “too wet” for hot composting. In this post we explain what this means and how to fix it.
What does ‘too wet’ for hot composting mean?
It simply means you have more water in the food waste than heat available to evaporate the moisture as water vapour. If you do not balance a wet mix, the waste will not get above 40°c, it will turn smelly and a lot of leachate will drain from the base. It happens from time to time and that is not uncommon. The waste is ‘too wet’ when the total percentage of water contained inside the waste cells is above 75%. As a rough rule of thumb:
- Garden waste has 40-60% water content
- Vegetable peelings have 70% water content
- Food waste is on average is 80% water content
- Foods like salads, juice pulp and cooked food have 90% water content
What are the signs my waste is ‘too wet’ for hot composting?
- Lots of liquid fertilser (brown liquid) leaking from the mesh plate.
- The waste in the HOTBIN smells putrid
- The temperature in the top layer will not increase above 30-40°c. (Poor aeration and a lack of new waste also prevents the temperature from rising above 40°c – so check these as well).
How do I fix (balance) waste that is ‘too wet’?
- Just add dry ‘easy to digest’ waste into your mix. The easy and available material to add is thorn up egg cartons or shredded office paper which helps absorb excess moisture. Avoid adding newspaper or cereal packet card for this task. They are not easy for bacteria to digest and will just end up as a mushy lump in your final compost.
- Adding a bulking agent (woodchips). Don’t forget to add the woodchips every time you add waste to aid airflow within the HOTBIN.
Remember: We keep learning how to keep our HOTBIN hot and happy as we feed it. Waste too wet can be fixed easily with balancing the waste, paper and woodchip diet.