title_body: Does coffee really need to be stored in an air-tight container?
upvoted_answer: How to store coffee beans is a much opiniated area. Degassing CO2 from coffee beans is most important right after the coffee has been roasted, since it would release a lot there and then gradually release less and less over days and weeks.
  If then beans can't release the CO2, then there will be a buildup and since CO2 tastes sour, then it will affect the coffees taste.
  
  Coffee should in general not be stored for too long after it's been roasted, since that will also negatively affect the taste. Storing it dark, dry and airtight will potentially keep it fresh a bit longer, but the best is in my opinion 1 week after roast and before 4 weeks after roast.