Fresh beans matter more than any machine. Buy whole beans roasted in the last few weeks, and only as much as you drink in a fortnight.
A light roast keeps the fruit and acidity of its origin; a dark roast trades them for body and the bitter-sweet taste of the roast itself.
A blend is made to taste the same all year. A single origin tastes of one farm and one harvest - and changes with it.
Grind just before brewing. A burr grinder gives even particles; a blade grinder gives dust and boulders that brew at different speeds.
Coarse for a French press, medium for filter, fine for espresso - finer grinds extract faster.
Use water just off the boil, around 94 °C, and about 60 grams of coffee per litre.
Bloom the grounds with a little water for thirty seconds, then pour slowly in circles.
Steep four minutes, press gently, and pour it all out at once so it does not go bitter.
An airtight tin in a dark cupboard. Not the fridge: the beans take on its smells.