Step 1: product selection
The key to successful Freeze Drying begins with the product selection process.
While it is true that anything can be Freeze Dried, the better the initial produce, the better the end product. That is why we manage our own growing programs all over the world.
Step 2: flash freezing
The products to be Freeze Dried are rapidly frozen to as low as -50ºC so as not to damage the often delicate structure of the item.
This locks the water in the product in place ready for the next stage.
Step 3: water is removed
The frozen product is then placed in a vacuum chamber and slowly heated until a point known as ‘the triple point’ is reached. This is a point where water can only exist in two states, solid (ice) or a gas (water vapour).
In this state over 90% of the water is vapourised out of the product while the majority of the nutritional value remains intact.
Step 4: airtight packaging
The final product is then packaged in air-tight containers where it can survive almost indefinately until needed.
The containers can be of any size or shape to suit individual production processes.
Freeze drying versus traditional drying...
Dried foods have played a huge part in food preparation for centuries. Freeze Drying is still a relatively new technique for drying food, but the benefits are immediately obvious as the table below demonstrates...
Traditional Drying Method:
- Products darken
- Products shrink
- Hard texture
- Flavour changes
- Flavour deminishes
- Limited shelf life due to moisture content
- Bulk density increases
- Nutrients denature
Freeze Drying Method:
- Natural bright colour
- Retention of shape
- Crunchy mouth feel
- Authentic original flavour
- Flavour remains
- Long shelf life due to low moisture
- Low density
- Retention of nutrients