So I try to grind about the same each time but for some reason if I don't hit the jackpot on adjusting my hand grinder I get sour or bitter coffee. Why is my Moka Express so finicky?
Actually, this question is self explanatory. I assume you only need some guidance and confirmation for what's going wrong.
A better known fact is:
- if your coffee is underextracted, it tastes sour.
- if your coffee is overextracted, it tastes bitter.
Now, let's tie up this to grind size:
- if your grounds are finer, your coffee overextracts if other conditions are kept stable.
- if your grounds are coarser, your coffee underextracts if other conditions are kept stable.
It's known that Moka pots are not controllable devices. So, all the other conditions (temperature, pressure, etc.) are nearly same each time. Thus, it's obvious that your grinding directly affects the taste of your cup. You should be consistent about your grounds. :)
And a final note, one of the jewels of this site is this extraction chart that you may check.
Reading the following makes me sad:
Moka pots are not controllable devices
A Moka pot (or Percolator) in fact is a controllable device. I use them since more then a decade with success with a much lower level of control as I list you here:
- Measuring temperatur
- Scientific paper about applied thermal engineering and moka pots
- Using laboratory equipment for brewing coffee with a moka pot
The easiest is to start with:
- Use a grinder
- Preheat the plate (I use 7-8/12 on electric stove)
- Use very warm (not hot and surely not cold) water
- Put the pot off of the plate before the coffee is finished as in the end you get water instead of coffee due to the coarser grains bleeding out earlier
- Do not temp the coffee, especially not hard, but get one of the cheap plastic tampers and tamp if slightly, but even