A Thousand Cups of Phin Coffee
SEAnergy is a Southeast Asian culture event. My team took the Vietnamese booth, and I was IC for a self-run coffee station serving roughly a thousand students.
The actual design problem
A phin filter takes four to five minutes. That is fine if you came to learn how Vietnamese coffee is made. It is unacceptable if you are between classes and want a drink.
Same booth, two completely different users. So we split the table:
- Learn — a printed instruction sheet, a phin, and someone to walk you through it. You make your own and you wait the four minutes on purpose.
- Make — pre-brewed, condensed milk, cup, go.
Almost every queueing disaster I have seen at a school event comes from making one line serve two intentions. Splitting the table costs you a metre of booth space and buys back the whole afternoon.
What we bought
Coffee grounds, condensed milk, filter paper, a kettle, a portable electric stove, a table cloth, ice packs. Bulk portable metal filters rather than single-serve, because at a thousand cups the consumable cost dominates everything else.
Booth footprint is 120 × 80 cm, so the two A1 prints — the how it works explainer and the write-up on what makes Vietnamese coffee Vietnamese — had to carry the education load without a person standing next to them. Vietnamese food is heavily French-influenced and leans salty, fish-sauce forward; the coffee is strong, with sweetened condensed milk doing the work that milk does elsewhere.
The iced option nearly did not happen. The teachers thought the ice logistics were a headache. They were right, and I would rather lose the cold option than lose the queue.
What I take from it
Event work is engineering with people as the load case. You size for the peak, you find the bottleneck, and you accept a worse average to protect the worst case. Four minutes of brewing is not a delay if the person chose it. It is a delay if they did not.