Whichever form of hops you choose to use, freshness is important. Fresh hops smell fresh, herbal, and spicy, like evergreen needles and have a light green color like freshly mown hay.

Old hops or hops that have been mishandled are often oxidized and smell like pungent cheese and may have turned brown. It is beneficial if hop suppliers pack hops in oxygen barrier bags and keep them cold to preserve the freshness and potency. Hops that have been stored warm and/or in non-barrier (thin) plastic bags can easily lose 50% of their bitterness potential in a few months.

Most plastics are oxygen permeable; so when buying hops at a homebrew supply store, check to see if the hops are stored in a cooler or freezer and if they are stored in oxygen barrier containers. If you can smell the hops when you open the cooler door, then the hop aroma is leaking out through the packaging and they are not well protected from oxygen. If the stock turnover in the brewshop is high, non-optimum storage conditions may not be a problem. Ask the shop owner if you have any concerns.