How to compost in a restaurant?

compost in restaurant

It is estimated that one third of the world’s food production is thrown away, and this amount of wasted food could feed 2 billion people.

Growing consumerism and mass production of food with a limited shelf life create large amounts of food waste. According to the data of the European Commission’s preparatory study on food waste, made in 2010, it is estimated that restaurants in the European Union are responsible for the generation of 14% of food waste per year. On a daily basis, restaurants throw away 60-80% of the total waste.

Zero waste cooking principle

In order to reduce the amount of wasted food, some restaurants apply the zero waste cooking principle, which we in Sunce adopted at the workshop of the ŠKMER Culinary Academy. This way of cooking requires good thinking and training of the staff. In addition to zero waste cooking, the amount of thrown away food waste can be reduced by composting. However, not all food can be composted.

In order to know what to compost, it is important to first learn about the composting process. Composting is the process of decomposing food scraps and other organic waste such as grass clippings and certain paper and cardboard items using heat, moisture, mixing and air flow, under controlled conditions. If we “lose” control over the process, unwanted unpleasant odors and rotting occur.

Although organic waste may seem repulsive to us, when it leaves the restaurant a large amount of organic waste can actually be turned into an organic substrate rich in minerals and biological compounds, through the process of composting. This organic substrate (compost) can then be used to fertilize and enrich the soil for local farmers and gardeners or for a vegetable garden or landscaped restaurant terrace. The fertilizer obtained by composting does not contain synthetic substances and is completely natural.

How does composting work?

A successful composting process depends on four main components:

1. Material

Successful composting relies on an equal mix of nitrogen- and carbon-rich materials. Nitrogen-rich materials are items like coffee grounds, grass clippings, and food scraps. Carbon-rich materials include dead leaves, newspapers and uncolored paper. If we have too much nitrogen-rich material, conditions can easily arise that allow rotting and unpleasant odors, and on the other hand, too much carbon-rich material slows down the composting process, so balance is important.

2. Temperature

Composting piles must remain warm so that the heat-loving microbes can properly break down the materials. A typical compost pile temperature ranges from 35-60 degrees Celsius. Microorganisms themselves, through their metabolism in the processing of biowaste, release heat, which manifests itself through an increase in the temperature of the pile. Compost piles should be turned or mixed every three or four days so that the materials can reach the warm center.

3. Moisture

In order for the microbes to break down everything in the compost pile, the materials must constantly have a certain level of moisture. There must be a balance in moisture levels, as not enough moisture will prevent microbes from breaking down materials, and too much moisture will slow down decomposition.

4. Air circulation

Without air circulation, composting materials will not break down properly. Lack of oxygen can also cause compost piles to give off gasses that smell similar to rotten eggs. Composting bins always have vents so that oxygen can circulate between the materials.

How to implement successful composting in larger restaurants?

Before you start composting inside the restaurant, you need to think about whether you want to compost inside the restaurant or just collect biowaste.

If you decide to compost inside the restaurant, you can get your composting device through the company Interzero. When purchasing a composter, keep in mind that restaurant composters are much larger than home composters and that they take up space. In addition, they also emit a specific smell and should be kept in a room with an air outlet or in the outside environment.

The positive side of the Interzero composter is that it can be used to dispose of the remains of meat products and even smaller meat bones, fish bones, egg shells, crab shells, etc.

Also, before you start composting, educate the staff about what type of food they can put into the composter. Connect with local farmers near you and donate compost created in your restaurant to them and enrich their garden with fertile soil. After everyone in the restaurant gets used to the composter, you will see only positive results of its use on the employees, but also on the local community.