How do you make perfect coffee with a moka pot?

The problem is almost always a combination of grind that's too fine and water that's too hot. When the powder is super fine, water passes through it slowly and the coffee over-extracts, becoming bitter. Start with a medium grind - coarser than espresso but finer than filter coffee. Fill the basket level with no tamping: the coffee should just sit there naturally. For the water, fill it up to the safety valve, no higher.

Extraction time doesn't matter much with a moka because almost everything depends on temperature. What you can control is using medium-low heat: that way the water rises slowly and the coffee doesn't get scorched. If you hear violent gurgling coming from the spout, the heat's too high. When the moka starts to "hum" gently and you see the foam rising, that's perfect. Take it off the heat when the flow slows down and becomes a slow drip.

One more thing: check the quality of your beans and when you ground them. Coffee that's weeks old will always be weaker, and if you're using a terrible blend, changing your technique won't help much anyway. Try a different brand if you're not happy with it - maybe something medium quality but fresh - and keep your grinder clean of old residue that messes with the taste.

The moka is a pain because it depends on way too many factors at once, and what nobody tells you is that the type of water you use makes an absurd difference. If the water is really hard, the coffee comes out bitter even if you do everything else perfectly, because the minerals speed up extraction.

That said, try this: use a medium grind (coarser than you think), fill the reservoir with room-temperature water, tamp the coffee in the filter with your finger but don't press like crazy (the secret is contact, not pressure), and put the moka on medium-low heat. Take it off the heat as soon as you hear the first strong gurgle and you'll see it's completely different.

The moka is all about balance between three things: medium grind (not too fine, not too coarse), room-temperature water in the reservoir, and moderate heat. For years I made the same mistake - I'd grind it super fine thinking that was better, and the coffee would come out bitter and weird; then I realized that with a moka, medium grounds are the sweet spot, cold water keeps you from over-extracting, and moderate heat gives you the right timing without rushing. Try filling the reservoir with tap water (not hot), use a grind similar to caster sugar, and wait for it to come out slowly without pressing anything - when you hear the gurgling and the aroma comes out the spout, take it off the heat. It should work out for you.

The moka has a detail that few people consider: the moment you remove the tank from the heat is just as crucial as everything else. If you wait until the coffee starts gurgling loudly, you've already over-extracted it; you need to take it off when you hear just the first sounds, even if it seems like hardly anything is coming out. Also try pouring a bit of cold water into the tank (not full) before assembling the moka: it slows down the extraction naturally and neutralizes the excess heat. Between the medium grind, the unpressed coffee, and this timing, the result changes quite a bit.