Silo UK in London’s Hackney Wick is the best-known circular restaurant in the UK. The original concept was a ‘‘restaurant with no bin”, where all waste on-site gets used up rather than thrown away.
Having eliminated 99.9% of its waste, Silo has proven itself on what seems like an impossible task, opening the way for others to follow.
Yet its success should not be surprising. Waste reduction is a basic principle of business operations and researchers have found circular restaurateurs can achieve significant cost savings.
So, how does a commercial kitchen do away with waste?
A frugal kitchen
Silo’s zero-tolerance waste policy has earned it many accolades, including a Michelin Green Star and an award for Britain’s most Innovation Restaurant from the Craft guild of Chefs.
The beating heart of the circular restaurant is of course in the kitchen. If an ordinary kitchen requires meticulous levels of planning, a zero-waste one needs even more logistical attention.
Silo only serves set tasting menus, allowing for tight planning around ingredient usage without the unpredictability of a la carte ordering. Waste reduction has also informed the cooking techniques. Fermented foods, which transform fresh ingredients into long-life preserves, drive the flavours at Silo.
Silo prides itself on creatively transforming everyday leftovers into house specials. Bread leftovers from the main courses get turned into the signature ‘siloaf ice cream sandwich’ at the end of the meal.
A key part of Silo’s waste reduction is only using food suppliers who align with the sustainable ethos. Silo’s cultivators and distributors deliver their wares in reusable, returnable vessels. This ensures no single use packaging ever enters the restaurant kitchen.
The zero waste ethos extends to the furnishings and fittings crafted from recycled materials. Material design company Smile Plastics was behind the design of the bar top, the dining tables, as well as chopping boards, mirror frame and coat hooks – all of which came from waste.
A food system that doesn’t work
Silo was set up to address the food industry’s role in the climate and biodiversity crisis through its throwaway attitude to produce.
An estimated one-third to 40% of food globally gets wasted every year. This uneaten food means crop nutrients and other resources that made their cultivation possible go to waste: these include land, water, pesticides, and in the case of livestock, antibiotics.
This stimulates demand for new farming inputs to make up the losses, causing a whole host of environmental problems. Some farming inputs, like certain synthetic fertilisers, are carbon-intensive to manufacture. Any addition of farmland can eat into biodiverse habitats while the use of pesticides can lead to wildlife declines. The use of livestock antibiotics on industrial scales pollutes waterways and contributes to antibiotic resistance.
How restaurants can support a circular bioeconomy
Restaurants can play a role in encouraging a food system that is more resource-efficient and less dependent on harmful pollutants.
This is partly due to their high-value position within the food system. Citizens spend more in restaurants than supermarkets and the global restaurant industry has been estimated at 5% of the overall global economy.
Reducing waste in the kitchen and on the plate means alleviating some of the pressures on the land and environment at the agricultural stage, cutting the need to order unnecessary inventory.
Circular dining also supports more ecological agriculture by leaving open the possibility of returning nutrients back to the soil. Often, the food that gets shipped and eaten in cities never gets turned back into compost and returned to food production.
The restaurant sector could also help shift practices at the cultivator end. As influential consumers of produce, once a critical mass of restaurants change suppliers to those that share their circular methods, this can support the economic viability of sustainable farmers.
Digital platforms for the circular restaurant
Achieving a circular restaurant is an organisational task. It involves planning kitchen outputs and inputs carefully so they align perfectly to eliminate any waste. Data-driven procurement is key here and for this, digital tech can help save time and effort here.
Winnow is an AI analytics platform that sells itself as a ‘commercial food waste solution’. Some major brands are clients, such as IKEA, which has reduced its food waste by 50% by implementing Winnow since 2017 in 23 of its UK and Irish stores.
Using cameras and scales coupled with AI, Winnow allows staff to record and analyse what is being thrown into their kitchen bins, enabling them to keep a close eye on what exactly it is they are wasting and how these could be put to better use. Three seconds is about all it takes for the AI to recognise the food discarded.
LeanPath is a digital food waste tracking programme on similar lines. After monitoring restaurant waste using scales and a camera, the programme produces a report suggesting the kinds of steps that might be taken to reduce how much food is thrown away.
Is it worth it?
Restaurants are a low-margin business and operators are under constant pressure to keep costs low. For this reason, circular technologies have to offer a reasonable investment for a restaurant to justify spending on them.
The competitive pressures of the catering and food service industries mean that those who have pioneered circular methods often try to convince others of the cost savings that can be achieved when waste is cut. Of course, the companies behind the waste-cutting smart solutions LeanPath and Winnow make the same claims in promoting their products.
So, is going circular viable? According to a study on food waste reduction in restaurants by WRAP and the World Resources Institute.
After a study of 114 restaurants across 12 countries, they found that those engaged in food waste reduction programmes had earned back 76% of their initial investment in a year. Most sites spent between $15, 000 to $20, 0000 over the three year period on waste reduction.
It also found that the average ratio between costs (how much the restaurant pays to implement waste reduction) and benefits (how much the restaurant saves on waste-related activities) was 7:1 over three years.
Cost-savings happen because the restaurants may no longer pay for waste collection and management costs, are able to sell food that would otherwise have gone into the bin, or have optimised their food and raw materials purchases.
Much of these costs consisted of purchasing smart food waste monitoring tech and systems that Winnoe and LeanPath offer yet many sites were able to pursue waste-reduction programmes without the help of new digital tech – using just the scales and pen-and-paper records they already had. The survey often found that the most creative and effective strategies for food waste came from kitchen staff.
Restaurant waste as feedstock
Instead of just cutting waste, some restaurants are using it to make new products that have market value.
Agricultural inputs are probably the most ecological product that food waste scraps could go towards. In some industries, the re-use and upcycling of materials like metal and wood is the purpose of circularity. In the food world, the most important type of circularity is one that returns the nutrients locked up in organic matter back to farm soils so the food production cycle can begin all over again.
In the US, one company offering solutions for such a circular food system loop is Hungry Giant, which sells and rents a bio-dehydration machine that sits on-site at restaurants and gobbles up any organic scrap that comes its way.
Hungry Giant’s machines offer a one-stop food waste handling solution that can churn out organic products by grinding and drying food leftovers until they are between 70 and 90% of their original volume. The Hungry Giant’s machines are also capable of digesting biodegradable biobased kitchenware.
Compost is the most obvious result of the process that the restaurant can sell on. However, it can also become higher value products: pet food and soil conditioners. To help restaurants recoup their investment in the machine more quickly, HungryGiant offers a service that collects and markets the resulting soil amendment to their farmer clients.
Circular restaurants as urban farms
Circular restaurants can also be testing grounds for the components of a full urban bioeconomy, demonstrating how onsite bioproduction from food waste can be slotted into day-to-day business operations.
These experimental farm-restaurants are high risk ventures as they simply have not been trialled much. Finnish chef and broadcaster Henri Alen, however, has the kind of profile that makes it easier to access capital, allowing him to pioneer on-site circular practices that could one day become more common.
Between 2018 and 2019, Finnish innovation fund Sitra supported Alen set up Restaurant Ultima where an in-house lab allowed the testing of insect farming using food preparation waste. Insect farming is gaining ground as a sustainable form of food and biomaterials production because insects are low-input ‘biofactories’ that metabolise simple or uneven feedstock into higher value chemicals and materials.
Ultima also has the capacity for mushroom-growing on coffee grains, algae growing, and other innovative food production methods.
Collective efforts
Wider adoption of zero-waste and circular practices by restaurants would require several things.
Regulation and services at the national and the local level would be the most important element in encouraging these practices. In France, composting is mandatory for households and businesses, for example, and a nation-wide food waste collection service would support efforts to pool and scale waste valorisation.
This national effort could help link restaurants to the wider bioeconomy. For example, local collection could divert food waste from restaurants and other sources to be processed in biorefineries into soil conditioners and compost at scale.
Even without government backing, the restaurant industry could also set up national or regional organisations that connect and coordinate individual restaurants, allowing them to share best practices around food waste and their valorisation.
