Paying the Price of Disposable Cups at Caffe Strada

By: Katie Latimer, Telegraph Green Project

In light of a fast-approaching deadline (2020) to achieve University of California President Janet Napolitano’s mandate of Zero Waste for all UC’s,  various groups and organizations on campus are working to “tackle trash” from many different angles. In an effort to reduce the impact on the waste stream from food containers and utensils, Cal Dining sells much of its on-site prepared food and beverages in compostable containers, and offers compostable to-go utensils. In addition, dining halls have implemented a successful reusable to-go container exchange program.[1]

However, according to a waste audit conducted in 2015 by Telegraph Green and Cal Zero Waste, on-campus food vendors are not the main source of food packaging waste that ends up in campus trash cans. The majority of waste – almost 70% – found in “Landfill” cans came from off-campus eateries (Figure 1). Furthermore, most of this waste was compostable, which indicates that simply requiring businesses to offer compostable packaging is not necessarily an effective solution; compostable waste that is sent to the landfill does not get used as fertilizer.


Figure 1: Waste found in “Landfill” cans in Sproul plaza waste audit, conducted Summer 2015 by Telegraph Green and Cal Zero Waste. Percentages are given by weight.

Previous studies at Western Washington University[2] and Tufts University[3] have implemented effective price signals which separate the price of a disposable cup from the price of the beverage. This “tax” is mathematically equivalent to a more conventional discount incentive: for example, a $3 cup of coffee might be sold as a $2.85 cup of coffee, with a 15-cent charge for a disposable cup and lid. A customer who opts to take the paper cup will pay the full $3, whereas a customer who brings their own mug will pay slightly less. However, the results of the cited studies show that when the discount is reframed as an additional charge (even if it really isn’t), customers will be more likely to use a reusable container. In terms of the classic “carrot versus stick” dichotomy, it would seem that, in this case, the stick is more effective in promoting sustainable behavior. Telegraph Green wanted to investigate whether this trend could be replicated at Berkeley.

Individual instances of reusable mug or thermos use by customers at Caffe Strada were recorded on a daily basis during a five-week control period (February 29 – March 28, 2016). At the end of the control period, the menu was changed such that all beverage prices were lowered by 15 cents, but an additional charge of 15 cents was added to the menu for a disposable to-go cup (Figure 2). The same data were recorded during the trial period.


Figure 2: Original (left) and revised (right) drink menus at Caffe Strada.

Informational signage was also posted near the register to inform customers about the motivation  for and implications of the new pricing structure (Figure 3). This was done primarly at the request of the café’s owner and manager, in order not to alienate regular customers.


Figure 3: Example of informational sign placed near register when new menu was posted.

A graph of number of individual instances of reusable container use over the control and trial periods is given in Figure 4.


Figure 4: Reusable beverage container use over the course of control and trial periods. Trial period began on Day 32.


Figure 4: Mug sales over the course of control and trial periods. Trial period began on Day 32.

It is clear that the new menu structure corresponds to a dramatic increase in reusable beverage container use. The average number of daily instances of reusable use increased more than six-fold, from 25 to 156. In addition, the number of custom Caffe Strada mugs (available for purchase at the register  during both periods) increased in roughly the same proportion, from 0.8 to 6.2 (Figure 5). Note that data from Earth Day (April 22) has been removed from this analysis, as the café conducted a promotional sale event for their mugs on that day.


We feel that this study shows a clear correlation between a price signal “tax” on disposable packaging and sustainable consumer behavior. Moreover, the methods employed require minimal short- or long-term investment or risk on the part of participating businesses, and even have the potential to lower overhead costs by reducing the amount of disposable packaging that must be purchased to maintain normal operations. A price signal merely takes advantage of consumer psychology by reconfiguring an incentive (the typical “mug discount” employed in many cafés) into a “tax.” This strategy could be ideal in the Telegraph district, where most food vendors do not have the luxury of time or resources to “go green” by, for example, installing dishwashing facilities or offering more expensive compostable servingware.

A parting note: when we met with the manager at the end of the study period to discuss his overall impressions, he told us that he planned to keep the “trial” menu up indefinitely, because it attracted positive attention from customers and offered an opportunity to engage their interest beyond a morning cup of coffee. Five months later, the menu is still up. Win-win?





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