title_body: Extending the Japanese Brewing Method to Espresso
upvoted_answer: The Japanese or Kyoto Method  and espresso a extremely dissimilar in their extraction methods and flavor profiles. It is truly like comparing apples and oranges.
  
  Espresso utilizes pressure as its main component whereas the Japanese method uses time as its main control.
  Espresso is concentrated more robust in its taste profile while the Japanese method is "more delicate with a lighter body".
  
  Here is an article explaining the idea of the Japanese method
  
  http://m.drinks.seriouseats.com/2014/03/japanese-style-slow-drip-coffee-cold-brewers-kyoto-yama-hario.html
  
  To your question of adding ice to your espresso. It's should be fine. There are a few methods of doing iced espresso. Here is one of the "clearest" recipes.
  
  http://m.wikihow.com/Make-an-Iced-Espresso
  
  So aside from flavor profile going in you should be good to go