First, let's identify the two main processes by which coffee degrades at home. Diffusion Aroma dissipates over time The more surface area exposed to air the dissipation increases Every time coffee is exposed to air, aroma trapped in the air is released and new space is created for diffusion process to continue Oxidation Oxygen in the air contacts beans/grounds and destroys the flavor Every time the coffee is re-exposed to air it increases contact to oxygen and accelerates thi