Freeze Drying - The Basics
Freeze drying (Also known as Lyophilization) is not only limited to freeze dried fruit and freeze dried snacks. There is an endless list of products that can be freeze dried. The amazing thing is that freeze dried products can be revitalized with a water. The texture and flavour will be very close to its original condition.
Almost any fruit, vegetable, herb, meat, seafood, juice or liquid can be freeze dried. You can even freeze dry ice cream!
There are three main criteria that determine how well the product will freeze dry and whether it’s feasible:
- Sugar or brix level - high sugars in some fruit, tend to caramalise during the drying process producing a hard, toffee like texture and flavour. The lower the sugar level, the better the outcome.
- Oil - products with a high oil content tend to become soft and at times, the oil actually separates out and pools on the trays. High fat cheese is a prime example - the moisture can be removed no problem but the oil remains and can cause issues.
- Alcohol - because of the low freeze point of alcohol, it won't 'freeze dry' under our commercial drying conditions.
Food that can be freeze dried
We have successfully freeze dried the following products and there are many more still to try:
- apple, banana, blackcurrants, blackberries, blueberries, cherries, kiwifruit, lemons, limes, lychees, mandarin, mango, orange, pineapple, raspberries and strawberries.
- beans, beetroot, broccoli, brussel sprouts, capsicum,carrot, cauliflower, garlic, kale, mushroom, peas, potato, spinach, sweet corn, sweet potato, tomato and zucchini
- basil, cardamon, chives, dill, fennel, lavendar, parsley peppermint, rosemary, sage, spearmint, thyme and turmeric
- beef, lamb, kangaroo and pork
- abalone, fish, scallops and squid
- most fruit and vegetable juices
- extracts in liquid or puree form
Freeze driers can be used to preserve just about any organic matter and are even used to restore wet documents and photos!