A single canned ingredient imported from the Netherlands has quietly fuelled Hong Kong’s daily hustle for the past 85 years, evolving from a simple dairy product into the soul of local diner culture. For decades, the Black and White brand of full-cream evaporated milk has been a crucial element in Hong Kong-style milk tea culture and craftsmanship, giving this popular drink in the city’s cha chaan teng – local cafes – its signature fragrance, thickness and smoothness. “Everything starts from a...