With this project, I aimed to demonstrate the potential of default nudge interventions in cafés. This involves changing the default milk served in drinks from cow’s milk to oat milk. In partnership with Brazier Coffee Roasters, I ran a three week trial during which oat milk was served by default. This resulted in an 80% increase in the number of drinks ordered with oat milk, from 17% of total orders to 30%, with a symmetrical decrease in cow’s milk.

The trial was complimented by 10 customer interviews, 6 staff interviews and 2 interviews with US-based café chains which have switched to an oat milk default.

Behavioural nudges have the potential as a low-intrusion, high-impact means of moving a population towards a desirable outcome. Default nudges have been proven to be one of the most effective forms of nudges. One manifestation of this are plant-based defaults which have been applied in a range of food and beverage settings. In the US, 3 small coffee shop chains have implemented some version of an oat milk default with universal success and with some evidence of positive impact to reduce cow’s milk consumption. In the UK, oat milk defaults have been tested with success in a few university cafes as part of academic experiments. However, oat milk defaults are almost untested in regular cafes in the UK, and certainly haven’t been comprehensively evaluated.

The best contribution I could have made was to conduct an experiment in a non-university cafe, to expand the evidence base in the UK. Alongside a field experiment, I conducted a number of interviews with customers and staff on the last day of the experimental phase and in the week afterwards. The aim of this was to get an insight into the views and lived experiences of those who had experienced the default nudge (customers) and those who had administered it (staff).

These two branches of data collection have naturally come together to create a holistic picture. The interviews have provided key insights of the strengths and weaknesses of the implementation of the default nudge which help to put the quantitative results in context.

The conclusion of the study was that an oat milk default nudge proved to be an effective intervention in an independent cafe. An intervention which was relatively easy to setup and run whilst having an immediate positive impact. Challenges were identified with staff training and as a result communication to customers could have been better.

I have produced a video to illustrate the findings of the study and promote the idea of plant-based milk default nudges to other cafe owners. If cafe owners can see the potential of this idea, the scale of impact could be significant.

A key take-away from this project was the value of building a partnership with a mission-aligned business. My partnership with Brazier Coffee Roasters meant that positive impact was created in the process of conducting the research. For a three week period the experiment led to tangible CO2e reductions in the café operations. Interactions between myself, staff members and customers have meant that this intervention at the heart of this study has reached a considerable number of people before being in an academic paper, policy report or presentation.