General home freezing guidance (source: WRAP UK)
While different types of food may require specific handling or treatments to achieve the best results from frozen storage, many techniques and available guidance or advice are general to all types of food.
- For best quality, freeze your food as soon as possible after purchase or, for home-made foods, as soon as soon as possible after cooking.
- Slightly undercook foods if you’re planning to freeze them. This will allow for cooking during reheating.
- Freeze unused leftovers within 2 days.
- For store-bought foods carrying a ‘best before’ date, it is safe to freeze them any time before that date, then defrost in the fridge and use within 24 hours.
- Cool your food before freezing to prevent raising the temperature in your freezer, e.g. use ice or cold water to cool containers of warm food.
- Separate products like steaks into separate bags, portions etc. Faster freezing will result in smaller ice crystals and better quality, so keep packs/portions as small as possible.
- Wrapping foods well in airtight packages is critical, as it helps avoid moisture loss and keeps air out, eliminating freezer burn.
- Write the date you are freezing the food on the pack so that you know how long it has been frozen for; use stock rotation if needed.
- Packaging for milk, cottage cheese and yoghurt are not moisture-vapour resistant enough for long term frozen storage and do not have seals which are airtight enough for optimum freezing, so transfer them to more suitable airtight packaging.
- The cartons that come with milk, cottage cheese and yoghurt are not moisture-vapour resistant enough for long term frozen storage and do not have seals which are airtight enough for optimum freezing, so it is advisable to re-package these products for freezing in more suitable packaging.
- Foil and cardboard take-away containers do not seal well. Plastic take-away containers may work if they seal well or can be overwrapped with a sealable freezer bag.
- Seasonings and flavours such as curry, garlic and chilli can strengthen or migrate between components during frozen storage and some can shorten shelf life e.g. salt has been found to accelerate the development of fat rancidity. You may want to add seasoning after thawing and/or reheating.
- Your freezer should be set at – 18° centigrade or colder.
- Where possible, avoid freezer temperature fluctuations (by avoiding loading warm food etc.), as these encourage large ice crystals and freezer burn to develop.
- Leave gaps between products while first freezing them (e.g. if freezing field berries). Freeze individual items/portions separately on a baking tray, then store them together when frozen.
- Don’t stack warm items together in the freezer. Allowing them to freeze separately will avoid large ice crystals, crushing and deformation.
- For fast freezing, place packages as close as possible to the cold evaporator in the freezer. Depending on type, this will be behind the back and side walls or in visibly apparent circuits built into the shelves.
- Use the fast freeze setting if you have one, particularly for large items.
- For separate freezers and fridge-freezers with dual thermostats, the freezer thermostat setting can be lowered to speed up freezing if there is no fast freeze function, but remember to re-set it to its normal storage temperature to avoid excessive energy use.
- Air trapped in packs can shorten shelf life and affect food colour, flavour and texture. Consider using a vacuum packing machine if you often freeze large amounts of food. As an alternative, use a straw to suck excess air out of sealable freezer bags.
- Improper frozen storage generally affects quality (rancidity, texture, freezer burn etc.) rather than safety (bacteria, moulds, etc.).
- Storage lives of home frozen goods can be shorter than industrially frozen products due to slower freezing and inferior packaging.
- Only thaw or use what is needed e.g. slices of bread for toast, portion of sauce, etc. keeping the rest in the freezer for when it is needed.
- Where possible, avoid freezer temperature fluctuations (by minimising door opening), as these encourage large ice crystals and freezer burn to develop.
- Rotate stock according to the date it was frozen, to minimise the length of time any food is kept in the freezer.
- Don't keep food in a freezer indefinitely; try to eat them within three months.
Thawing and use
- Freezing interrupts food spoilage. If a product is stored for a long time before you freeze it, you are advised to use it as soon as possible once thawed.
- You can cook, bake or toast some products straight from the freezer.
- Only thaw or use what you need e.g. slices of bread for toast, portion of sauce, etc. keeping the rest in the freezer for later.
- It’s best to thaw most foods in your refrigerator. This will help avoid parts of the food rising to temperatures sooner than others, which can promote bacterial growth. Some sources advise that thawing of products with meat, fish, dairy and eggs should only be done in a refrigerator.
- When thawing products such as meat and fish in a refrigerator, they should be kept sealed and placed on a tray or plate, and where possible placed at the bottom of the refrigerator to avoid spillage of drip and cross-contamination of other products.
- When thawing products such as meat and fish in a refrigerator, they should be kept sealed and placed on a tray or plate. Where possible place the plate at the bottom of the refrigerator to avoid spillage of leaking packaging and cross-contamination of other products.
- You can thaw food stored in sealed bags by placing the bags in cold water, refreshed every 30 minutes.
- Defrost foods in a microwave only if you intend to cook them straightaway. Microwave heating is uneven and may start to heat only parts of the product (higher temperatures accelerate microbial growth).
- Some products, e.g. baked goods, should be thawed at ambient room temperature, as extended periods at refrigeration temperatures increase staling.
- Thawing food before cooking it helps ensure that, during cooking, all the food is heated sufficiently to kill any harmful bacteria.
- If products are frozen raw in the home, then thawed and cooked, the product can be re-frozen.
- If products are bought frozen, then thawed and cooked, the product can be re-frozen.