The paper filter Brazil grew up with.
A small, flat-bottomed paper cone with a narrow outlet: the water lingers a little longer, so the everyday fine grind works — as long as it doesn't take more than 5 minutes.
What it is
The everyday way of making coffee in Brazilian homes: a paper filter in a plastic or porcelain holder, set over a pot or a thermos. The paper coffee filter itself was invented by Melitta Bentz in 1908 — which is why many Brazilians still call any paper filter a "Melitta".
Why it matters
The holder has a flat bottom and a narrow outlet, so water stays in contact with the coffee a little longer than in a V60. That's why the fine, supermarket-style grind works — and why the brew turns bitter if it takes too long.
In practice
Fold the filter along its seams so it sits flat against the holder, and rinse it with hot water to warm everything up. Use about a tablespoon of coffee per 100 ml, pour from the center out, and keep the whole brew under 5 minutes. Want it sweet? Sweeten the cup, not the water — sugar in the brew hides the coffee's own flavor.