Coffee beans are best preserved by storing them in an airtight container away from heat, light, and moisture — the four biggest enemies of freshness. Keep them at room temperature in a cool, dark cupboard rather than in the fridge or freezer, as temperature fluctuations can cause condensation that damages the beans. Always buy in small quantities and try to use them within two to four weeks of the roast date, as coffee begins to lose its flavor and aroma shortly after roasting. Avoid pre-grinding your beans until you're ready to brew, since ground coffee goes stale much faster than whole beans. If you do need to store a large supply, vacuum-sealed bags or containers with a one-way CO2 valve are ideal for maintaining freshness over a longer period.