1. Producers of shock freezing chambers claim that ice crystals do not damage food cells
The history of shock freezing began almost 100 years ago. Clarence Birdsey during his travels through what is now Northern Canada observed how local Inuit people use ice, wind, and low temperature to instantly freeze just-caught fish. Later Birdsey invented and patented several quick freezing machines. In 1929, he sold his company with the patents to Goldman Sachs and the Postum Company which eventually became General Food corporation.
The suppliers of blast freezing chambers claim that ice crystals are of an extremely small size and do not damage cells' membranes. Are there any references to scientific reports? Telling you about the small crystals, why a supplier does not specify its size? Why don't we have any microscopic images demonstrating those crystals? Why on a supplier's site there are no photos of products that were frozen and then defrosted using the equipment they offer to you?
Does a supllier of shock freezing equipment garantee that a taste of a product will be the same after defrosting? Where are the results of comparative tests on taste of products before freezing and after defrosting?
And why none of suppliers of shock freezing chambers or spiral freezers have any frozen food samples in their offices? Taste remains the same, they say. Why is it not possible to taste the samples then?
They do not even offer you to freeze your products and check the quality. Technology specialists usually have scientific reports on the performance of the equipment. Did they show it to you?
In most cases suppliers of freezing equipment does not pay any attention to weight, size and packaging type of the product you are intended to freeze: they deal with just one fugure - how many ton per day you want to freeze.
Lack of samples and bare assertions that the crystals will be of a smaller size should be a major concern.
2. Shock freezing enhances the quality of freezing by higher speed of freezing.
If a supplier tells you that "the faster freezing, the better quality", just ask which scientific data proves it. Scientific reports do not tell us about faster freezing as a condition for a better quality. Rather, there should be an optimal speed of freezing.
If every product has its optimal freezing speed, what is the freezing speed for your product? Does that shock freezing chamber/spiral freezer ensure the very speed you need? If the supplier does not know that an optimal speed is required, what does he sell to you?
3. Shock freezing ensures longer shelf life in comparison with conventional freezing.
Let's take a quote from a supplier's site: "Shelf life of shock frozen products (for instance, meat) is longer than in products frozen in regular freezing chambers. Fast frozen products maintain its properties during long storage better than fresh products. Therefore, shock freezing technology ensures the maintenance of fresh product quality and does this better than other methods of processing and storage".
Longer shelf life? To what extent? What is the shelf life for beef? And for venison? And for lamb? If fish is not glazed then what would be its shelf life? And for prawns? What does "long" stands for?
Promises to enhance quality and increase a shelf life are still only words. Ask a supplier: "We want to freeze fried fish. What would be the shelf life after freezing inside your freezing chamber? What is the basis of your claim? Are your ready to convert your promises into a written contract obligations?
4. Taste and nutrition value.
And one more quote:
"Due to prevention of drying, fast freezing prevents loss of aromatic and nutritional substances, resulting in maintenance of product's quality. Nutrition value and taste remain unchanged".
This is a blatant lie. We all have seen bags of frozen vegetables in supermarkets. Try to fry it. It is hardly possible! Vegetables float in water pouring into the pan. They do not look like fresh vegetables. It is clear, that some nutrients are lost
As your supplier to provide a report from an independent laboratory proving that nutritional value of the products remains the same after freezing in a particular freezing chamber. Perhaps somebody somewhere can make equipment for fast freezing that preserves nutritional value. But is it relevant for the specific equipment offered for you?
Ask your potential supplier to give you such report.
What percentage of taste would remain? 100, 90 or 50 per cent? How can your supplier prove this? Ask your supplier, when and how has he recently checked the quality of products frozen with its equipment?
5. Biochemical characteristics remain the same.
No thermal or chemical treatment of the products is used, - claim the suppliers of fast freezing equipment. The process is fast, so biochemical characteristics of product are not impaired.
And why do berries become sour after fast freezing? Why is it not possible to fry frozen vegetables?
Let's put strawberry into your shock freezing chamber and then defrost it. The taste will be like this strawberry was slightly stewed. Apparently, its biochemical characteristics have changed. What types of biochemical characteristics is the supplier familiar with and how are they measured?
And, of course, HEAT is a thermal treatment, while FREEZING is not, for some reason.
During heating, products are heated up to the water boiling point. And while freezing, thery are cooled down to crystallization point. Both processes are phase transitions.
6. Shock freezing decreases losses
What are the losses in weight of a product during freezing, storage and after defrosting? There are some losses during freezing. If a product is vacuum packed, there should not be any. What if the product is unpacked?
Which kind of freezing saves losses of which product and to what extent? Please, show me the table with the data on our products, that will be guaranteed by your equipment.
Ask the supplier if they have a food technologist on board or somebody who can calculate the loss in products after freezing?
What would be the loss in case of pork frozen in your freezing chamber? First, at freezing, and then after defrosting and what would be the difference in weight?
Do not hesitate to ask these questions. Equipment supplier does not have any answers. The answers to these questions could be found on the Internet, and the supplier would not answer them.
Conclusions:
All written above proves one simple thing. Shock (blast) freezing is a myth that is sold to you. There is no standard for Shock freezing. Suppliers will not provide you with any scientific or laboratory data.
There are only two reliable facts about shock freezing:
it saves space at a production site, as long as it allows to produce a bigger volume of frozen products per square meter
the faster a product is chilled, the less bacteria growth.
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