In a bid to reduce single-use waste, Hong Kong’s Consumer Council conducted 60 mystery shopping visits across 20 chain stores—including McCafé, Starbucks, and 7‑Eleven—between November and December 2024, uncovering inconsistent policies, poor promotion of discounts, and practices that undermine the very purpose of bringing your own cup. Separately, the council tested 18 reusable tumblers for insulation, leakage, and safety, naming top performers while flagging capacity discrepancies and stability concerns.
The BYOC Reality Check: Discounts That Often Go Unseen
The council’s undercover shoppers visited 20 outlets serving freshly made coffee, bubble tea, and convenience store beverages. Every single store accepted reusable cups, but the experience varied widely. Over 70% of customers reported being “satisfied” or “very satisfied”—with bubble tea shops earning the highest marks.
However, the goodwill stopped short of genuine waste reduction at some major chains. At McCafé, staff in three separate tests prepared drinks using disposable paper cups before pouring the contents into the customer’s reusable cup. Similarly, at 7CAFÉ, an employee first emptied ice from a plastic cup into the shopper’s vessel, then made the coffee—still using a disposable container. These practices directly contradict the “green operation” image these brands project.
Moreover, while 11 of the 20 outlets offer financial incentives—typically HK$1 to HK$5 off per drink, and one coffee shop giving a 10% discount—many failed to display these offers clearly. Shoppers often learned of the discount only after asking, and some staff incorrectly applied or missed the deduction entirely. The council urges retailers to improve in‑store signage and train employees to consistently apply eco‑incentives.
Cup Size Matters: When Your Reusable Cup Doesn’t Fit
Physical compatibility also caused hiccups. At one convenience store, the shopper’s tumbler was too tall to fit under the coffee machine’s dispenser, forcing staff to brew into a disposable cup first. That store offered no guidance on acceptable dimensions. In contrast, another convenience chain proactively shared height and capacity limits (no taller than 15 cm) on social media and in some branches—a practice the council recommends all adopt.
Tumbler Test: Heat, Cold, Leaks, and Surprises
Alongside the store survey, the council evaluated 18 reusable cups priced from HK$80 to HK$425, focusing on insulation, leak resistance, and material safety.
Heat retention: Only two models—NOC (HK$354) and STANLEY (HK$854)—kept water above 60°C after six hours. Six others stayed above 50°C, including Starbucks, Zojirushi, and WOKY. All three plastic models performed poorly, with temperatures barely above room temperature.
Cold retention: Eight cups kept chilled water below 11°C after six hours, notably Starbucks, Decathlon, and STANLEY. Again, plastic models lagged.
Leak testing: Twelve cups survived an inverted one‑hour test without a single drop. Six models leaked when turned upside down, including Thermos, % Arabica, and STANLEY. However, when placed on a 45° slope, none showed significant seepage. STANLEY’s top‑heavy, narrow‑based design made it prone to tipping on a 10° incline, whether empty or full.
Safety: All 15 stainless‑steel cups passed heavy‑metal migration tests (chromium, iron, nickel) within European standards. Two models, PO: and PoleBear, showed trace amounts in a third extraction, but at safe levels.
Capacity claims: Five cups—MUJI, 24BOTTLES, Decathlon, National Geographic, and PoleBear—held over 10% less liquid than advertised, failing European labeling standards. Only NOC, Starbucks, and two RICOCAFE models matched or exceeded their stated capacity.
What This Means for Hong Kong’s “Plastic‑Free” Future
The council’s findings highlight a gap between intention and execution. While consumers are increasingly willing to carry reusable cups, many stores still use disposable containers behind the counter. Combined with poor promotion of discounts and inconsistent staff training, the environmental benefit is diminished.
For shoppers, the council offers practical advice: choose a cup that fits your go‑to store’s machine, check the actual capacity before buying, and always ask about discounts—even if not advertised. For chains, the message is clear: go beyond accepting BYOC—actively support it. Better training, clear signage, and genuine “green” preparation steps can turn a well‑meaning policy into real waste reduction.
As Hong Kong pushes toward a less disposable culture, every cup—and every store’s policy—counts.