How to Read Vacuum Pressure Gauge

[easysurfer]

I recently spent my IRS refund on a present to myself and got a chamber vacuum food sealer. I like the sealer, but one [-]stupid[/-] simple question.

How do I read the pressure gauge?

Now where in the instruction booklet does that say what the numbers mean, instead just says the pressure gauge measures the pressure . That's great but not for the average consumer like me.

I attached a picture of the built-in gauge on the sealer.

Does the Bar scale indicate the percentage of air evacuation? 0 when the machine is off, but then when pump is running, increments in 10% (.1) until 100% (1 on the scale). Just a guess on my part.

p.s. Got an avocado sealed in a storage bag for 1 day and counting. Still looks fresh .

 

[sengsational]

Atmospheric pressure is about 30 mm Hg. So -30 is a complete vacuum. So your guess seems spot-on.

 

[zedd]

I dunno about the gauge. But here's a video on a cool (boiling) experiment to do in a vacuum chamber:

 

[Johanson]

1 bar is the metric equivalent 29.5 inches of HG. 1 bar is roughly 1 atmosphere.

 

[GalaxyBoy]

1 bar is roughly one atmosphere, so if you could draw it down to -1 bar it would be a perfect vacuum (depending on atmospheric pressure that day). Inches of mercury ("Hg) is simply another unit of pressure. You could convert either of these to pounds per square inch (psi) but the maker of that gage chose not to use that.

 

[easysurfer]

Thanks. I'll just go by the bar scale then as if in 10 percent evacuation increments. Makes things easier for me without having to think in terms of atmospheric pressure and mercury ).

 

[marko]

For uses here the term "perfect vacuum" is probably appropriate.

Having spent 30 years in the industrial vacuum business (think space chambers etc) -30 bar is only the beginning of the vacuum realm so I had to wince at the term!

 

[HFWR]

As someone familiar with ultra-high vac systems, good luck getting a "perfect vacuum" using a food sealer. [emoji12]

My system shuts off automatically at some level that doesn't appear to be adjustible.

 

[Lakewood90712]

29.9999999.......... is as close as the scientists can get on earth. No need to try that.

Want to spend some more money ? get an electronic micron gauge for reading high vac.


The real challenge I see is getting the best bags at the lowest cost.

 

[easysurfer]

For me, the goal isn't about getting a "perfect vacuum" but more if I retrieve a frozen pork chop from the freezer, I want to be able to recognize that as a pork chop instead of some piece of meat covered with ice crystals .

 

[Lakewood90712]

For me, the goal isn't about getting a "perfect vacuum" but more if I retrieve a frozen pork chop from the freezer, I want to be able to recognize that as a pork chop instead of some piece of meat covered with ice crystals .

Part of the problem. Drawing a vacuum will be drawing moisture out of the meat to the surface and the slowly freeze in the home freezer. Without an industrial flash freezer. Can't see how to do it at home.

 

[easysurfer]

Part of the problem. Drawing a vacuum will be drawing moisture out of the meat to the surface and the slowly freeze in the home freezer. Without an industrial flash freezer. Can't see how to do it at home.

Even with an old time FoodSaver (the originals better than the fancy shiny ones, in my opinion), I've had good seals of meats (like a burger or chicken leg quarter) that didn't have much ice crystals. Sure there were some, but a lot less than in a regular ziploc bag.

The chamber vacuum should even be better than the external FoodSaver types.

 

[LOL!]

For uses here the term "perfect vacuum" is probably appropriate.

Having spent 30 years in the industrial vacuum business (think space chambers etc) -30 bar is only the beginning of the vacuum realm so I had to wince at the term!

A perfect vacuum has no pressure at all. The 30 on the scale was mm of Hg and not bar anyways. The inner scale is in bar and "bar" is one atmosphere at standard temperature at sea level or something close to that. The -30 is meant to indicate that the pressure is 30 mm of Hg less than the pressure outside the chamber.

So if you took your vacuum sealer and put it in a decompression chamber for divers, then you would have some interesting readings.

easysurfer should be able to see the gauge needle peg to all the way to the limit when the vacuum is created. Anything less would suggest a leak.

Spoilage is caused by oxygen mostly, so one just needs to get rid of the oxygen and not all the other gases. Any residual oxygen can be used up by the living cells in the food you are trying to store as long as no new oxygen is allowed into the system.

 

[ls99]

Even cheaper solution. Stick a lit match into zip lock bag with whatever else. Zip the bag. When flame goes out oxygen is gone.

No I have not tried it. In theory it works!

 

[ERD50]

For me, the goal isn't about getting a "perfect vacuum" but more if I retrieve a frozen pork chop from the freezer, I want to be able to recognize that as a pork chop instead of some piece of meat covered with ice crystals .

You can come pretty close just dipping a regular zip-style bag in water. The water weight will push out most of the air, and conform to the pork chop.


-ERD50

 

[Jerry1]

Interesting as a gauge would be, I would think that any residential food saver would just shut off at a particular level of vacuum. Mine sucks out the air and when it seems it can't suck no more, a light goes on that indicates it's sealing. Can't imagine what I would do different with the gauge. What model is the one from the original post?

 

[easysurfer]

You can come pretty close just dipping a regular zip-style bag in water. The water weight will push out most of the air, and conform to the pork chop.


-ERD50

I saw a demo of this method on youtube. Pretty nice.

 

[easysurfer]

Interesting as a gauge would be, I would think that any residential food saver would just shut off at a particular level of vacuum. Mine sucks out the air and when it seems it can't suck no more, a light goes on that indicates it's sealing. Can't imagine what I would do different with the gauge. What model is the one from the original post?

The model is a Vacmaster VP120 chamber vacuum sealer.

One advantage is during the vacuuming, the air in the chamber and bag gets sucked out but not the liquids. Soups even work as long as cooled. Unlike the regular external channel types where the juices can get pulled into the pump.

Another advantage is chamber bags are much cheaper than the foodsaver type bags.

The chamber machines cost more initially, but in the long run if you seal enough bags, the cost goes in your favor (like laser vs inkjet printers for ink costs).

 

[samclem]

Part of the problem. Drawing a vacuum will be drawing moisture out of the meat to the surface and the slowly freeze in the home freezer. Without an industrial flash freezer. Can't see how to do it at home.

Maybe a small pan of very cold salt water (??20 deg F?) and dunk the porkchop and bag in to get it below 32 deg F quickly? Start with a cold porkchop (from the fridge). The cold water in contact with the porkchop bag will do a much faster job of getting the heat out of it (better heat transfer solid-to-liquid than solid-to-gas) and thereby reduce the drying out of the meat.
The ice bath could start with cold tap water from the fridge, add ice from the freezer and salt to melt the ice, let it get below 32 deg F and stay liquid.

I've also heard it is a good idea to put a wet paper towel in the bag with the meat. The water in the towel serves as a sacrificial source of H2O for formation of the ice crystals, reducing the amount of water drawn from the meat. I don't know if it works.

 

[easysurfer]

Interesting as a gauge would be, I would think that any residential food saver would just shut off at a particular level of vacuum. Mine sucks out the air and when it seems it can't suck no more, a light goes on that indicates it's sealing. Can't imagine what I would do different with the gauge. What model is the one from the original post?

You asked about which model I have. Here are some pictures. As far as chamber vacuum sealers, the unit is actually on the small side. But the thing is built like a tank, over 50 lbs.

I have a picture next to my old FoodSaver as reference.

 

[LOL!]

I have friends who use ziplock bags and suck the air out with their lungs by using a straw.

 

[RetiredGypsy]

If you're curious how accurate it is, the local Extension office from whatever university hosts it should be able to test if it's calibrated.