Why should I buy coffee freshly roasted?

The freshness of the coffee beans can have a direct impact on the quality of the coffee.

Sugars in the coffee bean begin to setup during the roasting process and continue forming through 3-5 days after the day of roasting. Grinding and brewing the coffee after the 3-5 days will yield the best possible extraction that the coffee can provide.  After those days, as the coffee is exposed to oxygen, it will be oxidizing and loosing the oils and flavor after about 3 months.  This is why it is best to purchase as freshly roasted coffee as possible.  Then, the next hurdle is not grinding the coffee until just before use.

Two weeks after opening a sealed container of ground coffee the grounds will become stale and over-oxidized. If the grounds are kept in a sealed container they can last up to a month. When grinding the beans immediately before grinding, one has more control over the grind size, the oxidation, and ensures that the beans oils, and taste, won't be lost through the water molecules in the air. ​