title_body: Decaf coffee, how to make our own
upvoted_answer: In short: Very probably, you will lose the very best part of your coffee.
  
  Caffeine is highly soluble, yes. But, also the other lipids and aromatics, too. So, you cannot obtain the benefits of specialty coffee if you ruin that first brew. The main taste we gain from coffee grounds are received from the soluble aromatic oils in the coffee. You don't want to loose them by pouring.
  
  Normally, decaffeination process is made when the beans are green. That's why the aromatics are kept inside the beans when the beans are over-hydrated and then dried (in the Swiss process, which is the common way recently) a few times in a cycle to near completely remove the caffeine.
  
  You can check the decaffeination process in the following question:
  
  
  How is decaffeinated coffee made?
  
  
  And also watch a nice explanatory animation here.
  
  Still, if you wonder how to use the grounds for a second time, please see this discussion:
  
  
  Brewing with the same coffee grounds twice?