title_body: How to reduce sourness in my moka-pot brew?
upvoted_answer: What I immediately notice is that you say the entire brew process takes only 5-10 seconds. Even for a 1-pot moka, this seems way too fast.
  
  Vary some other parameters:
  
  
  Start with cold water in the bottom chamber. While not the best way to brew with Moka in general, it might slow down the brewing process. You should want your moka brew to take closer to 30-60 seconds (my preference, for example). Longer time will allow the sourness to be offset by bitterness (compounds which are extracted after water has been in contact with grounds for a longer time).
  Try brewing the coffee as pour-over. This will give you a more neutral preparation that will allow you to determine if the coffee itself is of good quality and too your liking.