Indonesia · Yogyakarta
Kopi joss is sweet black coffee with a glowing charcoal ember dropped in the glass, a Yogyakarta street tradition since the 1960s. What it does; is it safe?
Kopi joss is sweet black coffee with a glowing ember of charcoal dropped into the glass. It comes from Yogyakarta in central Java, where street stalls have served it since the 1960s.
The name is onomatopoeic — the joss is the hiss when the charcoal hits the coffee.
The charcoal is glowing hardwood, briefly quenched. It fizzes violently, then sits at the bottom.
The claimed effect is that it reduces acidity — which is chemically plausible, since ash is alkaline and would neutralize some acid. Vendors also claim it settles the stomach, which is folklore.
What it definitely does is add a smoky note and a distinct texture from the fine ash.
Charcoal from hardwood is essentially activated carbon, which is consumed medicinally. The practical concerns are what the charcoal was made from and whether anything was used to light it.
Street vendors use plain hardwood embers from a brazier. Do not attempt this with barbecue briquettes, which contain binders and accelerants.
Kopi tubruk — fine coffee and sugar in a glass, boiling water poured on — then a small ember of plain hardwood charcoal from a fire, tonged in.
It is a spectacle as much as a drink, and it is a genuine local tradition rather than a tourist invention.
The stalls around Yogyakarta’s main railway station, Tugu, are where it is usually sold, from angkringan, the low-cost night food carts of central Java, alongside rice parcels and grilled skewers. A glass costs very little, and the charcoal is fished out or left at the bottom as you prefer.
The equipment this actually requires — not a shopping list, the shortest route to doing it properly.
Aluminum · 130 ml · not induction
Over ninety years old, sold by the million, and misused by almost everyone who owns one. Brewed properly — low heat, pre-boiled water, off the heat at the first gurgle — it is one of the great cheap coffees.
Best for: One or two strong cups on a gas or electric cooktop, at almost no cost.
51 mm (2.01 in) portafilter · 15 cm (5.9 in) wide · pressurized baskets
About six inches wide, heats in forty seconds, and makes a decent drink at an entry price. It ships with pressurized baskets that fake crema from any grind — which is exactly why it works for beginners and why it stalls after a year.
Best for: A tiny kitchen, a first espresso machine, or a second machine for an office.
