Effects of different coffee storage methods on coffee freshness after opening of packages

The aroma of freshly roasted coffee is one of its most enticing but also ephemeral qualities. Coffee aroma starts deteriorating after roasting, and appropriate packaging and storage are needed to preserve its freshness. After a coffee package has been opened, the protective atmosphere changes, accelerating the loss of freshness and staling of coffee. This study compares four different methods for storing whole roasted beans after opening the package: (i) transferring beans into airtight canister, (ii) closing original package with tape, (iii) closing with clip and (iv) using a package with an integrated screw cap. The aroma was analyzed during storage by gas chromatography mass spectrometry (GC/MS), after grinding. Freshness indices were determined as ratios of GC/MS signal intensities of two selected compounds and used as indicators of storage stability (also called index), to compare different storage approaches. The 2-butanone/2-methylfuran index was found to be best suited to assess coffee staling for such conditions. The screw cap packaging was the best performing storage method. Using a clip, re-closing with tape or transferring beans into a container resulted in a faster loss of freshness. Findings were in line with observed changes in oxygen and carbon dioxide content inside the respective package. While changes of coffee during the primary shelf-life of coffee have been discussed in a series of publications, this study is one of the first that sheds light on how consumer practices can influence the secondary shelf-life of whole bean coffee.