ChatterBank1 min ago
Gasbags!
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I vaguely remember hearing, many years ago, that food manufacturers would put a quantity of an inert gas in bags of things like crisps, tortilla chips, sweets, etc. This was apparently (from what I can remember) to ensure that the product remained fresh for several weeks, while allowing the fragile contents to be cushioned against squashing in packing. But it could not just be air, because that would cause oxidation and the product would deteriorate quickly. Is this true, or was it ever? And what gas was it?
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It is true and continues. Lots of results from Google. Here's just one.
https:/
https:/
"Argon is a rare and VERY expensive gas."
It's not that rare, Eddie, and not very expensive. Not my own work but here's a few facts I quickly discovered:
On Earth, the vast majority of argon arises from the radioactive decay of potassium-40. Though inert, argon is far from rare; it makes up 0.94 percent of Earth's atmosphere, according to the Royal Society of Chemistry (RSC). By Chemicool's calculations, that translates to 65 trillion metric tons and that quantity is increasing over time as potassium-40 decays.
The reason I looked it up was because I was surprised when you said it was rare and expensive. I know that it is used extensively in fairly large quantities and among its uses are in specialist welding and pumping into diving suits to insulate the diver from the cold. It can be bought retail for about £40 for 20 litres (at 200 bar) so I'm sure Walkers' Crisps can afford a bottle or two to pump into their packets of salt n' vinegar.
It's not that rare, Eddie, and not very expensive. Not my own work but here's a few facts I quickly discovered:
On Earth, the vast majority of argon arises from the radioactive decay of potassium-40. Though inert, argon is far from rare; it makes up 0.94 percent of Earth's atmosphere, according to the Royal Society of Chemistry (RSC). By Chemicool's calculations, that translates to 65 trillion metric tons and that quantity is increasing over time as potassium-40 decays.
The reason I looked it up was because I was surprised when you said it was rare and expensive. I know that it is used extensively in fairly large quantities and among its uses are in specialist welding and pumping into diving suits to insulate the diver from the cold. It can be bought retail for about £40 for 20 litres (at 200 bar) so I'm sure Walkers' Crisps can afford a bottle or two to pump into their packets of salt n' vinegar.
New Judge, I’m afraid you have some misconceptions about both the cost of argon gas and its use in food packaging; EDDIE51 is correct in what he says in his post.
It is true that argon is abundant on this planet. However, abundancy bears no relevance to the cost of the gas in any given cylinder. The sole factor involved is the cost of the processing equipment to extract any given gas from air. Argon extraction is costlier to extract from air than carbon dioxide, oxygen and nitrogen but specialised plants have enabled BOC/Linde to sell argon at very approximately double the cost of oxygen per 50 litre cylinder for example. The costs you mention do indeed fall within this category.
However, here is where your misconception comes in. These prices are all for industrial grade argon. Industrial grade gases can be regarded as reasonably high purity but are not pure in the sense of 100% argon. Argon at 98% purity can be called pure and indeed the BOC PureShield Argon range meet this criterion. Nevertheless, PureShield argon and ArgoShield range from BOC/Linde are industrial grade argon designed for welding and other industrial applications. They cannot be used in food processing.
So, let’s move on to food grade argon. It’s known as N5.0 and N6.0 and must be used in food processing due to EC regulations. N5.0 is known as zero grade argon and has a minimum purity of 99.999%. A 50 litre cylinder of N5.0 currently costs £214.00 from BOC/Linde. The N6.0 variant with a 99.9999% purity is £677.11 for a 50 litre cylinder. Both can also be regarded as about 10.57 cubic metres of gas.
As far as crisps are concerned, I trust you can now see why it’s very costly for manufacturers to displace air in crisp bags with argon. Extrapolating the figures I’ve provided on the industrial scale needed in food manufacturing makes the entire process very costly. Furthermore, without boring you with the technical details, N6.0 is the only grade allowed for many food applications.
My laboratories use piped argon rather than via cylinders and we use a low purity argon , the N6.0 grade plus an even higher grade for some specialised applications. The argon is held in huge external storage tanks and the stuff is not cheap even though bulk cost is marginally cheaper per litre than cylinder held argon. The government research facilities I lurk in use the N6.0 grade only. I absolutely agree that pure grade argon is indeed rare and expensive.
Although I’ve mentioned BOC/Linde is this reply, other atmospheric gas suppliers charge about the same for argon as they often use the same processing facilities.
It is true that argon is abundant on this planet. However, abundancy bears no relevance to the cost of the gas in any given cylinder. The sole factor involved is the cost of the processing equipment to extract any given gas from air. Argon extraction is costlier to extract from air than carbon dioxide, oxygen and nitrogen but specialised plants have enabled BOC/Linde to sell argon at very approximately double the cost of oxygen per 50 litre cylinder for example. The costs you mention do indeed fall within this category.
However, here is where your misconception comes in. These prices are all for industrial grade argon. Industrial grade gases can be regarded as reasonably high purity but are not pure in the sense of 100% argon. Argon at 98% purity can be called pure and indeed the BOC PureShield Argon range meet this criterion. Nevertheless, PureShield argon and ArgoShield range from BOC/Linde are industrial grade argon designed for welding and other industrial applications. They cannot be used in food processing.
So, let’s move on to food grade argon. It’s known as N5.0 and N6.0 and must be used in food processing due to EC regulations. N5.0 is known as zero grade argon and has a minimum purity of 99.999%. A 50 litre cylinder of N5.0 currently costs £214.00 from BOC/Linde. The N6.0 variant with a 99.9999% purity is £677.11 for a 50 litre cylinder. Both can also be regarded as about 10.57 cubic metres of gas.
As far as crisps are concerned, I trust you can now see why it’s very costly for manufacturers to displace air in crisp bags with argon. Extrapolating the figures I’ve provided on the industrial scale needed in food manufacturing makes the entire process very costly. Furthermore, without boring you with the technical details, N6.0 is the only grade allowed for many food applications.
My laboratories use piped argon rather than via cylinders and we use a low purity argon , the N6.0 grade plus an even higher grade for some specialised applications. The argon is held in huge external storage tanks and the stuff is not cheap even though bulk cost is marginally cheaper per litre than cylinder held argon. The government research facilities I lurk in use the N6.0 grade only. I absolutely agree that pure grade argon is indeed rare and expensive.
Although I’ve mentioned BOC/Linde is this reply, other atmospheric gas suppliers charge about the same for argon as they often use the same processing facilities.
Well to be fair, it's all in the definition of inert gases. The phrase was formely used to refer to the Noble Gases and argon is a member. Nitrogen is not a member of the group, but I will concede that the definition nowadays includes gases which prevent hydrolysis and oxidation when used in reference to food.
Helium, Nitrogen and some CFC's can fall within the category of inert gases for food packaging
Helium, Nitrogen and some CFC's can fall within the category of inert gases for food packaging
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