Two Letters Re: The Tire Shop Option for Nitrogen Packing Food Storage Buckets

Concerning the article titled “The Tire Shop Option for Nitrogen Packing Food Storage Buckets”. My dear friend said that I should let everyone know that a much easier way to use nitrogen for your buckets is to pick it up at your local welding supply. You could then do 1,000 (who really knows how many) or more buckets in the privacy of your own home. – Steph in Colorado

I’ve been packing buckets and other containers for years without the use of dry nitrogen, but I’m pretty sure the contents are actually nitrogen packed. If we look at the major constituent gases that make up our atmosphere we get primarily: Nitrogen (78%), Oxygen (20.9%), Argon (0.9%), and all other gases excluding water vapor (0.04%). Water vapor makes up from 1% to 4% depending on the humidity. Adding these numbers may look like more than 100%, but when there is more water vapor in the air, the percentage of the other gases is slightly smaller as an overall percentage. Given these numbers, when food or other items are packed with a sufficient quantity of oxygen absorbers and desiccants, within a few days the oxygen is removed (actually converted and sequestered as iron oxide). Likewise, the water vapor is absorbed and sequestered in the desiccant. If you take the normal atmosphere and remove the oxygen and the water vapor, you are left with dry nitrogen and a tiny bit of trace gases, nearly all of which are inert. I’m not sure if using nitrogen helps, but I’ve never used it, relying instead on larger oxygen absorbers and additional desiccant. – LVZ in Ohio

JWR Replies: Yes, oxygen absorber packets can be effective, but the nitrogen wand method is more reliable and less expensive. The biggest problem with oxygen absorber packets is that there is no sure way to know whether or not a package of packets has been compromised. Once they are exposed to the atmosphere for a few hours, they are “used up”, and rendered useless. Thus, we have to depend on the honesty of everyone in the chain of ownership of the packets from the manufacturer, to the wholesaler(s), to the retailer. In many instances, large bags of 1,000 packets are resealed into smaller bags, for retail sales. All it takes is a minor slip up, and they become useless. These days, I don’t put a lot of trust in the integrity of worker bees. Few are willing to own up to their mistakes.

Using a CO2 or nitrogen “wand’ (or “probe”) to displace air from buckets is far less expensive than using oxygen absorber packets if you pack more than 20 per year.. It can also useful for re-sealing a single bucket, if you only need to use part of a bucket’s contents. I highly recommend the wand method for anyone that plans to pack more than ten buckets. If you want to buy your own CO2 cylinder then all you’ll then need is a valve, a three foot length of plastic tubing (1/4-inch inside diameter), and an 18″ long piece of stiff copper tubing (1/4-inch outside diameter) for use as a wand. With a nitrogen cylinder, you will also need to include a pressure regulator to drop the pressure from 2,100 p.s.i.! If you are uncertain about how long you should leave the valve open with your particular cylinder and bucket size, you can use a lit fireplace (long) match or the stub of a candle, as test. Position it inside the bucket, just under the lip. Simply observe the sweep second hand of a wristwatch. The count you take from when you open the valve fully to when the flame is extinguished is the count to use for subsequent buckets. Add two or three seconds, just to be sure. One word of warning: if the contents have been stirred into an airborne dust, they may form an explosive atmosphere in the container (think grain elevator explosion). If this condition exists, the oxygen has not been displaced yet, and an ignition source (match) is introduced an explosion may occur. This could make your day very interesting. Flour, dried milk, and even household dust are explosive if they are airborne and in the right concentration.