Let’s learn how a chamber vacuum sealer works...

When I got my chamber vacuum sealer, I was surprised, that it is not as straight forward as the household "sucking" vacuum sealers. 

 I know, that a lot of home-cocktail enthusiasts really don't have access to this technology - however a lot of bartenders read my blog, which work in professional environments - and most hotels (and a lot of restaurants and bars with kitchen) just have chamber vacuum sealers. Hence this blog post is dedicated to those. 

I cannot give perfect instructions - because a lot of chamber vacuum sealers are a bit different - and also any different product you like to vacuum seal is different. But understanding the settings, will help you to come to a far better result!

Functional principle

This information is pretty available in the internet - but I repeat it to be a slight more complete guide.

A suction vacuum sealer is sucking out the air from the bar. Obviously this has the disadvantage that liquids are also sucked out. Depending on your vacuum sealer, this can make a big mess - or it can seriously damage your sealer as well. Also - due to the nature of the plastic bags, you need special structured bags - so the air can even get sucked out, when the both sides “cling” together.

In contrary a chamber vacuum sealer (as picture on top of the post - which is the model I own), is removing the pressure out of the whole chamber... basically the surrounding of the bag. The Bag is open, hence the pressure is also removed out of the bag. Then after most of the air pressure is removed, the bag is sealed and the chamber is returning to normal pressure.

That sounds easy enough. But what are the different settings and where can you fail?

Settings:

While a lot of things look in our time digital, they aren’t. A vacuum sealer is one typical piece which looks very evolved and high tech - but is based on very simple and analog principles.

1. Time of vacuum pump operation:
1. The first setting is the time, how long the vacuum pump has to run. Yes - you are not changing the vacuum itself - you are setting the time (it seems to be the same, but it really isn’t). 
2. This indicates, why I can’t give you perfect instructions: because every vacuum sealer is different: smaller ones have smaller (and weaker) vacuum pumps, bigger ones have stronger vacuum pumps. Hence you have got to get used to the chamber vacuum sealer you are using. 
3. The longer the pump is running, the lesser air pressure you got. All chamber vacuum sealers have an air pressure gauge. I am using it just as an indication - I am not using it to “dial” the exact pressure in. But it is helpful, if you are understanding, at which time the minimum air pressure (max vacuum) is achieved.
2. Time of holding the vacuum:
1. This is the setting I didn’t understood directly. When a “vacuum” is pulled, there is still a difference between bag and chamber. This is natural, because the open bag is pressed together. Also - some materials need time to “release” the air. 
3. Time of sealing:
1. Simple: the longer the time, the longer the heating strip is sealing the bag. Obviously you could easily melt through the material with too much time.
4. Strength of sealing:
1. Additional to the time of sealing most vacuum machines have different levels of sealing (low, medium, high, and no sealing). 
2. Thin bags needs a lower setting - while very thick bags and aluminum material needs the high setting.
3. Using the vacuum sealer for marination, compressing, infusing & vacuum canning - will require, that you turn of the sealing (you don’t want to waste bags - or sometimes you don’t use bags at all, which would result in potentially damage the sealing strip.

Liquids: 

My biggest gripe about chamber vacuum sealer is, that they can handle liquids, but they are not made for using liquids. The chamber is always shallow, which makes it hard to vacuum liquids - and in smaller vacuum sealers you can only vacuum very small jars (which is a pity, as vacuum canning is really great).

The biggest issue (besides of overestimating the quantity of liquid) is, that liquid starts to boil at lower temperatures when the air pressure is removed. Boiling water results into expanding volumes, which means, that vacuum bags can occasionally burst, but at least things are overflowing etc.

• Dial in lesser time on your vacuum timer. Personally I have good results when using 18-28 seconds - but as said, different vacuum machines have vastly different pumps.
• Make sure, that the liquid is cold. The warmer the liquid, the lower is the boiling point. Fridge temperature is better than room temperature. And room temperature is better than sous vide temperatures etc.
• Try to angle your bag - which helps to prevent spillage.
• When vacuum canning, leave an adequate free space (again liquid expanses). Oh for canning, don’t tighten the lid - just close it very “softly”. The vacuum will pull and the lid will be tighten automatically. Vacuum canning is not pressure cooker canning. While expiration of a product is pushed bag, there might be still pathogenic bacteria. Let me know, if you like to know more about food safety in the bar.

Know step by step instruction how to vacuum seal in a chamber vacuum sealer:

1. Dial in your timer for the vacuum. Dry and sturdy food can be timed for longer (minimum air pressure), while liquids need to be short. 
2. Dial in your holding time. If you are experiencing, that your bags still has some air inside after sealing, you probably have a too short holding time. For liquids, as long as you are below the boiling point (which you can literally see), you can hold it much longer. Hence the air pressure can come to an equilibrium between bag and chamber. For vacuum canning, you might even crank the holding to the extreme. I didn’t found any disadvantages yet, by having a long holding time - except maybe that you loose time. Obviously if you want to have a strong vacuum with moist ingredients (above the boiling point), you want to keep it briefly, otherwise you will have a lot of clean up on your hands.
3. Dial in your timer for the sealer. A normal bag will seal (at the medium setting) properly at around 2 seconds. If you have got moist ingredients, which might leak out, you might want to give it an extra second.
4. Dial in your sealer strength. I normally have it on medium. Thin bags are usually not recommended for things I am doing (sous vide, vacuum marination etc.) - they might work well with e.g. hamburger patties (as long as the bag is heat safe) - as thin bags cannot compress the burger physically. But no burgers for bartenders...😁. Please remember to turn off the sealing, when you are using the chamber vacuum machine for marination, canning, compressing...
5. Add the bag / item into the chamber and close the lid. Most machines will start automatically the process, as soon as you are lowering the “hatch”.

It is all about gaining experience with the machine. If your liquids are starting to boil, observe at how many seconds this happens - and adjust the timer (as said, it is less practical to note down the air pressure itself - because you cannot directly adjusting it). 

And just note: your experience with one machine will help you, but it won’t give you there perfect solution. You still have to adjust to other machines and have to adjust your settings.