How to package food for cooking under vacuum and at low temperature

It is possible to obtain results very similar to those obtained when cooking vacuum foods without packaging the food under vacuum. So, if you do not have a vacuum packaging machine, you can use this method to cook foods at low temperature without vacuum packing .

Test the result and decide if a homemade vacuum packer can be a good investment for your kitchen. The results obtained without packing the food under vacuum before cooking at low temperature are similar. But they will never be as good as if you vacuum-packed food before cooking .

Types of vacuum packaging machines for food

When it comes to vacuum food packaging, there are different tools that allow us to perform this task, within a fairly broad price range.

Thus, we can distinguish three main types of machines for vacuum food packaging :

  • Manual vacuum packaging pumps.
  • Vacuum packaging machines without hood.
  • Vacuum packaging machines with vacuum hood.

The vacuum packing machines with vacuum hood are the ones that offer the best results and offer us many advantages.

However, this type of machines for vacuum packaging is intended for use in professional kitchens . And both their dimensions and their high prices make them unsuitable for vacuum packaging in the kitchens of our homes .

For these reasons we will not spend more time talking about vacuum packaging machines with vacuum bell. We will focus only on the other two main types of machines for vacuum food packaging.

Types of packaging for vacuum food packaging that we are going to cook at low temperature

We can vacuum food packaging using:

Flexible plastic bags .
Or rigid plastic containers , glass or other materials.
It is possible to use these rigid containers to vacuum-feed food and then cook them at low temperature. But it is more practical to cook using flexible plastic bags , because they use much less space. This is a great advantage both during cooking and if we cook these foods with the aim of preserving them later.

Whether we use plastic bags or use rigid containers to package the food we are going to cook, we must make sure that the container used is suitable for cooking food inside.

We must also make sure that the container in which we vacuum pack the food we are going to cook will withstand the temperatures and cooking times we are going to subject it to .

Keep in mind that not all plastic bags intended for packaging vacuum foods can be used to cook food inside.

Many of them should only be used to pack and preserve vacuum foods but not to cook them inside. If in doubt, consult the manufacturer of the vacuum bags you are going to use if they can be used to cook food inside.

Vacuum Food Packaging with Manual Vacuum Pumps

Manual vacuum packaging machines are very simple and inexpensive .

To use them we need to use special plastic bags that incorporate a valve that works in only one direction. This valve allows the air to be extracted from the bag and also prevents air from entering it again inside it.

For the rest, these bags are very similar to the typical Zip bags for food packaging . And, just as with Zip bags, the main point to take into account when buying this type of bags for food vacuum packaging is the use we are going to give them. If we intend to use them to cook food under vacuum and at low temperature, the bags should be suitable for cooking food inside .

We must make sure that the bags we buy are safe to cook with the temperatures and cooking times we are going to use .

In addition to these plastic bags with valve we will only need a manual pump . This pump will be the one that, once connected to the valve of the bag, will allow us to extract the air out of the bag until it empties into it.

The procedure to follow to vacuum food packaging using a manual vacuum pump is very simple:

We introduce the food that we want to pack inside the plastic bag with valve. It is advisable not to fill the bag too much . This way we can place the manual vacuum pump on the vacuum valve comfortably.
We close the plastic bag completely using the zip-type closure tab. At this point it is not necessary to worry about the air that has remained inside. But we must make sure that the closing tab is completely closed at all its points .
We place the bag on a flat surface.
We plug the vacuum hand pump into the vacuum valve of the bag.
We operate the manual vacuum pump, pumping as many times as necessary until all the air is extracted from the bag.
Advantages of packaging machines based on manual vacuum pumps
Thinking about packaging vacuum foods and then cooking them at low temperature, the main advantages of vacuum vacuum food packaging machines based on manual vacuum pumps are:

It is a much cheaper system than buying a vacuum packaging machine .
It allows us to try vacuum cooking techniques without making a large financial outlay.
It is a method to pack very comfortable and simple food .
It is a device that occupies very little space . Something to keep in mind if our kitchen is not very big.
Being a manual system does not consume electrical power .
Disadvantages of packaging machines based on manual vacuum pumps
The most important disadvantages of manual pumps for the vacuum packaging of products that we will later cook at low temperature are :

The results obtained are not as good as those obtained with an electric vacuum packaging machine . This is due to the fact that they allow us to achieve a lower degree of vacuum inside the vacuum packaging bags.
Vacuum packaging with a manual vacuum pump is slower and more cumbersome than that carried out with an electric vacuum packaging machine. It is more uncomfortable for regular use.

How to package vacuum food with a domestic vacuum packer and plastic bags

The technique to pack vacuum foods that we must follow when using domestic vacuum packaging machines and plastic bags is very simple:

  • We take the plastic bag in which we are going to pack the food and  fold its top part  (the part that is open) outwards about 5 or 10 centimeters.
  • In this way  we will avoid staining the upper part of the bag , facilitating the subsequent operation of vacuum packaging and sealing the bag.
  • Insert the food inside the plastic bag, being careful not to stain the outside of it.
  • We go around the top of the bag that we had previously folded.
  • We lift the lid of the vacuum packing machine and place the bag with the food on a flat surface.
  • We place the open end of the bag on the area designated for this purpose of the vacuum packaging machine.
  • We close the lid of the vacuum packing machine and press the air extraction button of the machine.
  • By doing so, the vacuum pump will draw air from the bag.
  • And finally it will seal the end of the bag to prevent the air from going back inside.

How to package vacuum food with a domestic vacuum packaging machine and plastic rolls

If we want to pack a vacuum food with a homemade vacuum packaging machine and plastic rolls, the process is very similar to the one we have described for the case in which we use plastic bags.

First of all we have to  introduce the end of the plastic roll in the vacuum packing machine and press the sealing button . In this way we will seal the end of the roll to be able to form a bag of the size that we need.

We can repeat this operation a second time, moving a few centimeters the end of the plastic roll inside the packaging machine and resealing the end of the plastic roll. In this way, we will have  a double seal that will be safer and avoid possible breakage of the bag or possible leaks of air inside the bag during cooking .

If our vacuum packaging machine seals perfectly well and we have never had problems of this type we can make a single seal.

Vacuum-free food packaging in ZIP-type bags for cooking at low temperature

This technique consists of using ZIP-type plastic bags . That is, the well-known plastic bags that have a hermetic closure system that allows us to close the bag preventing air from entering it.

The first thing to keep in mind is that we must make sure that the ZIP bags we use are suitable for cooking food . Well, as we have explained, not all plastic bags for food packaging serve to cook food inside them .

Once we have ZIP bags suitable for cooking food, the technique is very simple:

  • We introduce the food that we want to cook inside the ZIP-type plastic bag.
  • We apply pressure with the fingers on the closing tab, although without closing it completely.
  • We leave open about a quarter of the length of the closing tab.
  • We introduce the bag in a container filled with water, submerging it enough so that the water level reaches practically the level of the closing tab.
  • We take care that the water does not enter inside the bag.
  • When performing this operation, the pressure that the water exerts on all points of the plastic bag will displace the air contained within it.
  • Then, carefully, we close the rest of the ZIP bag until it is completely closed.
  • Once this operation is finished, we extract the closed bag with the food inside it from the water bath. 

We will see that most of the air contained in the bag will have disappeared and we will have managed to pack the food almost empty .

We just need to practice this operation a few times. Once we have mastered the technique, we will be able to pack food inside ZIP bags leaving practically all the air contained inside the bag .