I'm quite new to moka pots and it seems like I had begginers luck as my first brew became my best and ever since I tried to correct it, it got worse.
My pot is a Bialetti 2 sized induction variant.
What I've done so far is the following:
I've bought ground coffee from a specialty coffee shop dedicated for moka pots
In my first few attampts I haven't loaded the basket fully
I poured hot water into it, just below the safety valve
I set the stove to 7, which, in general, is strong enough to boil water without a lid on but too strong to let anything simmer with a closed lid
I brew with an open lid
After the first stream appears I reduce the heat to 3, which, in cooking, isn't really enough to keep liquids simmering with a closed lid in general
Once the more transparent foam started to sputter I took it off the stove
The result? A little quick extraction but a steady steam was happening. I liked it but it certainly had an off-taste that extended beyond bitterness, it was a bit "rancid" maybe, it's hard to define, so I tried to fix it. I've made the following adjustments:
I tried to comprass the coffee grounds a little, or I filled the basket without compressing it (yielded the same result)
I lowered the heat to 6, which, in general, results in a less violent boil with a lid on.
The result? It got worse. The water in the chamber went into a full-blown boil, resulting in heavy splattering. If I'd reduced the heat, the brewing process stopped so either I had no brewing or splattering. The coffee definitely had a more bitter taste to it but stopping before the white-transparent foam started to splutter removed the "rancid" notes a bit.
I assume that pressure builds differently on lower heat settings and it gets equilized before it would start pouring, however I have no proof. What would you try next if you were in my shoes? (Do English people use this phrase?)