How do you quick-chill sous vide cooked foods?
The goal for rapid chilling is to minimize the time of cooked food staying within the bacteria ''danger zone'' temperature range of 5°C - 55°C (41°F - 131°F). It also preventsmoisture from forming in the bag - and hence ice crystals - which may affect storage quality.
To do this: once the pouches have finished cooking, completely submerge them - still sealed - in an ice bath containing equal amounts of ice cubes and water for about 1 hour. Then, remove the pouches from the ice bath, dry them prior to refrigeration (for a few days) or freezer storage (for a few months). If you notice that the pouches are no longer airtight, it's best to repackage the cooked items in a new bag and make it airtight
again prior to storage.
Note that storage temperature is critical: in general it should always be at most 5°C (41°F) (which is good for 3 - 5 days refrigeration), but colder is better for prolonged storage.
It's advisable to label the pouches with the date and time of storage (so you don't forget). It's also good practice to portion your servings in separate bags for easy reheating later.
What's the difference between shorter and longer term cook-chill?
Cook-chill means that ingredients are cooked, chilled, stored and reheated later. The length referred to here is the storage time. Generally, we'd define ''longer term'' as storing more than 5 days. The method of storage (refrigeration vs. freezing and usage of vacuum sealer) is affected by the desired storage time and pasteurization, altough all cook-chill processes involve a rapid chilling (or quick chill) process prior to storage.
Can I pre-prepare raw food, seal and freeze it and cook from frozen later?
Yes, you'll need to add additional cooking time for the food item to thaw in the sous vide water bath. The speed of thawing depends on the items thickness, shape and cooking temperature. It could range from an additional 30 minutes (for 2.5cm/1 inch thickness) up to double the minimum cooking time of recipes.
For prolonged freezer storage (more than 5 days), do make sure you seal it properly with a vacuum sealer to avoid freezer burn. Avoid adding salt if you're seasoning raw ingredients prior to sealing and freezing as it tends to create a 'cured', firmer texture that's less juicy when cooked.