See how long frozen food lasts before quality drops.
Freezer burn is dehydration, not spoilage: water sublimates from the food surface into the freezer air, leaving dry greyish patches that taste of cardboard. Food frozen at or below -18 C stays microbiologically safe more or less indefinitely, so every figure here is about eating quality rather than safety. Three things drive the rate. Fat content matters most, which is why oily fish lasts three months and lean beef nine — fat oxidises even when frozen. Packaging that excludes air roughly doubles quality life, and temperature swings from frequent door openings drive repeated partial thawing that accelerates the whole process.
Quality life
Months = baseline x packaging factor x temperature factor x door-opening factor
Temperature factor
Factor = 1 - 0.09 x (degrees above -18 C), held between 0.35 and 1.4
General food quality guidance, not a safety determination. Frozen food held continuously at or below -18 C (0 F) remains safe indefinitely, but any food that has thawed above 5 C for more than two hours may be unsafe regardless of these timeframes. Follow your national food safety authority's advice and discard anything you are unsure about.
No. Freezer burn is moisture loss and fat oxidation, not bacterial growth, and food held at or below -18 C remains safe indefinitely. The affected patches simply taste dry and stale, and can be trimmed away. Quality, not safety, is what these timeframes describe.
Sublimation needs somewhere for the water vapour to go and oxidation needs oxygen. Removing the air removes both, which is why vacuum-sealed portions commonly last close to twice as long at good quality as the same food in a freezer bag with air trapped inside.