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What is Vacuum Evaporation?

Charity Delich
Charity Delich

Vacuum evaporation is a technique that is frequently used by manufacturers to preserve food and beverage products. When food or drinks are vacuum evaporated, they can usually be kept for longer periods of time without going bad. Vacuum evaporation may also be used to concentrate these products. For example, evaporated milk is essentially fresh milk that has been vacuum evaporated, resulting in a richer, creamier product that has a longer shelf life than fresh milk. In other words, evaporated milk is a concentrated dairy product.

Vacuumed food products can have several advantages over their fresh food counterparts. The most obvious benefit is product preservation. Consider, for instance, canned fruits and vegetables that undergo vacuum evaporation. These canned goods last a much longer period of time than fresh produce items, which can spoil within days of being purchased from a grocery store.

A can of evaporated milk, which is made through vacuum evaporation.
A can of evaporated milk, which is made through vacuum evaporation.

In general, vacuumed food products also have a lower weight and volume. This means they usually require less packaging. In addition, their smaller size can make them less expensive for companies to transport and store. For example, a can of frozen orange juice concentrate not only has a longer shelf life, but it also requires less packaging and less storage space than a fresh bottle of orange juice.

The use of pasteurization and modern refrigeration have made bottled dairy products more popular than vacuum evaporated milks.
The use of pasteurization and modern refrigeration have made bottled dairy products more popular than vacuum evaporated milks.

A vacuum evaporation system can be used to preserve or condense food and beverage products. Vacuum evaporators are devices in which liquids are evaporated from a low density substance in order to make a high density, more concentrated product. Many food and diary products require high vacuum evaporation techniques in order to achieve a usable, long lasting end product.

A vacuum evaporator usually contains three key elements. The first element is a heat exchanger that transmits heat from steam to the food product. The second element is a vapor-liquid separator, and the last element is a vacuum producer. This is typically operated by a steam ejector or a mechanical pump.

The type of vacuum evaporator used for a particular type of food or beverage product will vary depending on the product’s liquid characteristics. Factors to be weighed may include concentrate properties, foaming, temperature and timing impacts, and quality and flavor recovery. Cost is also often a factor for manufacturers.

Vacuum evaporation also occurs outside the food industry. In this context, it is often more specifically referred to as vacuum thermal evaporation and is used in the semiconductor, microelectronics, and optical industries. In general terms, vacuum thermal evaporation is a method of depositing thin films onto cool surfaces.

Discussion Comments

Oceana

You always hear experts say that fresh food is best for you. They say that fruits and vegetables contain mysterious ingredients yet to be discovered by scientists, and when we eat processed versions of fresh food, we are not getting all the untold benefits they have to offer.

So, if I have the option, I eat fresh food. If certain types of fruit are unavailable during off seasons, I will buy the frozen kind, because that’s better than no fruit at all.

I do keep a supply of canned food in my cupboard for emergencies, though. In case of a natural disaster, like the ice storm we had a few years back where the power was out for weeks, I have food on hand to help me survive.

Perdido

@lighth0se33 - I used to have to drink that vacuum evaporated orange juice as a kid, and I really didn’t like it. I knew it was good for me, but it tasted kind of bitter.

It looked really disgusting coming out of the can, too. It looked like pumpkin puree - a sticky, gooey mess. I still recall the sound of chunks of it plopping into the pitcher.

Like magic, when my mother poured water over it and stirred it, it turned into orange juice. It was hard for me to believe that the solid mess could become anything drinkable.

lighth0se33

Vacuum evaporated orange juice fits in my freezer so much easier than bottled juice squeezes into my refrigerator. The juice concentrate comes in a cylindrical can, while the fresh juice comes in a plastic bottle with a handle that juts out and takes up space.

Because it’s cheaper and saves space, I buy the frozen juice. I have to feed a family of five, so any savings are appreciated.

Secretly, I prefer fresh orange juice, though. It just seemed to have a fuller, better flavor. I won’t let my family taste it, because then they would want it all the time.

cloudel

I find it strange that canned foods are vacuum evaporated. They usually have juice in them, so I always just thought they were packed in their own liquids.

They do last a lot longer when canned. Beans and corn in a can have expiration dates years from the purchase date. A can of green beans in my cupboard will be good for another three years, but a batch of fresh green beans that I bought last week went bad after about five days.

I usually prefer the taste of fresh vegetables over canned ones, because canned foods are often super salty. Several types of canned vegetables are offered as low sodium varieties, though, and if I know that I won’t be able to eat the amount of fresh vegetables that come in a certain bag or package, I will buy the low sodium canned version.

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    • A can of evaporated milk, which is made through vacuum evaporation.
      By: Fotofermer
      A can of evaporated milk, which is made through vacuum evaporation.
    • The use of pasteurization and modern refrigeration have made bottled dairy products more popular than vacuum evaporated milks.
      By: Budimir Jevtic
      The use of pasteurization and modern refrigeration have made bottled dairy products more popular than vacuum evaporated milks.