Oxygen Absorber Packets
- Our oxygen absorbers consist of an air proof package holding 100ea 300cc or 500cc oxygen
absorber packets. Once it is opened, the unused packets must immediately be put in another
air tight package. A small mason jar with a new canning lid should do the trick.
- Oxygen absorber packets will not absorb moisture.
- If you are planning on using oxygen absorber packets in preserving your edible dry
goods, you must be able to seal the container. The oxygen absorber packets absorb the
oxygen, leaving a partial vacuum. If your container isn't air tight, the oxygen in the air
being sucked into the container will eventually load the packets with oxygen, and
introduce oxygen back into your product.
- Air is about 78% nitrogen and 21% oxygen. That's about 646 cc of oxygen in an empty #10
can. Seeds take up between 50% and 75% of the volume in a can, leaving perhaps 161-323 cc
of oxygen in a filled #10 can.
- The oxygen absorber packets will actually absorb as much as twice or more of their rated
capacity. They are not quite twice as big as the oxygen absorber packets used in the study
on this page.
- We put one oxygen absorber packet in the #10 cans and two oxygen absorber packets in the
6 gallon Super Pails.
- The oxygen absorber packets used by canneries and in the following study will absorb 300
cc of oxygen.
A Short Lesson On Oxygen Absorbers
Oxygen absorbers come in a plastic bag. Each
absorber packet has a special barrier to prevent its contents from making contact with
Within the last ten years the advent of oxygen absorbers has brought a revolution to
the food storage industry. Their use has increased the storage life of foods and has made
the job of putting away food for long term storage much simpler. There are two types of
oxygen absorbers used for the storage of Food, "B" absorbers and "D"
absorbers. The "B" absorbers require moisture from the food they are packed with
to perform their action. A good example would be beef jerky or dehydrated fruit that
hasn't been dried until it is brittle. The "D" absorbers contain their own
moisture and are better suited for dry pack canning because there isn't enough moisture in
correctly dried food to activate the "D" absorbers. The "B" absorbers
will last a year after they are manufactured but the "D" absorbers only last 6
months. This is important for you to know so you won't buy a bunch of absorbers, pack them
away for two years, and expect them to do their thing when you finally open them. The
"B" absorbers also work much slower as they must first absorb moisture from the
food they are packed in before they will absorb any oxygen. You can generally leave them
out for 2 hours before they reach their advertised minimum absorbing capacity. Because the
"D" absorbers have their own moisture built into them, they start absorbing
oxygen immediately when opened and reach their advertised minimum much quicker, generally
within 20 minutes.
Oxygen absorbers perform their action through a chemical reaction. They contain iron
powder which reacts with the oxygen in the air causing the iron powder to rust. When all
the iron powder has oxidized, the oxygen absorbers are "loaded" and the
absorbing action stops. Remove the oxygen from an active absorber and the chemical
reaction stops. Put them back in the air and the reaction starts again until the iron is
Each bag of oxygen absorbers contains a
light pink capsule. This capsule turns to a light blue color when the bag is opened. It's
there to tell you if an unopened bag has been compromised. It doesn't automatically mean
that all the oxygen absorbers inside are bad as it will change color soon after the bag is
Number of oxygen absorbers needed: We sell 500cc absorbers. They will absorb
500+ cc of oxygen. A #10 can holds 13 cups or very roughly 3300cc. Air is 21% oxygen. So
that empty 3300cc #10 can actually has about 683cc of oxygen in it. If you take a full cup
of beans it takes about 0.375 cups of water to bring the water level up to the top of the
cup. I've found this to be true with most of the whole seeds I've measured including wheat
and rice. This figure is important because it also tells you how much air is in the can
when it is full of seeds - 37.5%. With a #10 can full of these products, you now have
about 256cc of oxygen left in the can. If you are canning a powder you probably have less
air than this but foods like macaroni would have more. Already you can see that one 750cc
absorber should do the job nicely, in fact it's a bit of overkill. A 300cc absorber would
also do the trick. We use one 500cc absorber in each of our #10 cans as we'd rather have a
bit of overkill than a little oxygen left in the can should the absorber become loaded.
Actually, on the cans, this is a lot of overkill as the absorbers we use now actually have
more than twice as much oxygen absorbing capacity as what they are rated for.
A 6 gal bucket holds 22,740cc. Going through the above calculations, a full 6 gal
bucket of grain or beans has about 1791cc oxygen left in the container at sea level. You
will need four of our absorbers if you are packing up your food at lower elevations. Our
facility is at 6,000 feet and at this altitude there is only an equivalent of 1484 cc of
oxygen in the thinner air. Again, because of the oxygen absorber's significant under
rating, we only use two 500cc absorbers in the buckets as they will absorb more than twice
their rated capacity
Oxygen absorbers are over rated to give you a fudge factor if you should leave them out
in the air too long. Generally, you have about 20 minutes before they reach this
advertised minimum. There are variables that determine how fast the oxygen absorbers work,
so you shouldn't leave them out any longer than you absolutely have to. But why not get
every bit of absorption you can out of them? May I suggest you leave only enough out in
the air to take care of maybe 1 or 2 minutes of operation?
The following test was made with Fresh Pax D750 absorbers.
How do you know when an oxygen absorber is spent???
absorbers have a greater capacity than is listed on the package. This is intentional to
allow for some exposure of the packet to air during your packaging process. None of this
is necessary if you have a new, sealed bag of oxygen absorbers. However, if for any reason
you want to check them, this is one way to get it done.
It's impossible to see how much
life is left in an absorber by looking at it or feeling it. The only sure way is to
actually see how much oxygen it will absorb. One way to do this is to tape the absorber to
the bottom of a bottle. The larger the bottle the better. In my tests I used a gallon
pickle bottle. Put the bottle upside down inside a pan of water being careful to set it
straight down so no water enters the bottle. As the days pass and the absorber takes in
oxygen, the water level will rise in the bottle. When it stops rising, use a magic marker
and mark the water level, then take the bottle out of the water and fill it with fresh,
new air. I did this by blowing 5 or 6 full breaths of air into the bottle. Then sit it
back down into the water. When the water level stops rising again, mark the level again
then fill it with new air and repeat the process until the absorber won't pull any more
water up into the bottle.
In my tests it took 3 1/2 cycles for the
D750cc absorber to get loaded using a 1 gallon bottle.
The next step is to see how much air was absorbed. Pour some water into the bottle, put
on the lid, and turn the bottle over. Add/remove water until the level lines up even with
the top line you made with the magic marker. Turn the bottle right side up, remove the
lid, and pour it into a container. Now, repeat the process for each of the other water
level marks and add this water to the first water in the container. After you have
finished, measure the amount of the total water you poured into the container and this
will give you a pretty good estimate of the cubic volume of oxygen your absorber absorbed.
Realize this is not 100% accurate if you take the atmospheric pressure and air
temperature into account. As the barometer or room temperature fluctuate, they will make
the water level go up or down in your bottle independent of how much oxygen has been
absorbed. If you have a barometer, you may also wish to record the barometer reading each
time you finish a cycle. You can correct for temperature by making sure the room
temperature where you are doing your test is the same temperature each time you complete a
cycle. Altitude will also have an effect on how much water gets into the jar. The higher
the altitude the higher the water will rise for the same amount of oxygen being absorbed.
This is because the air is thinner the higher you go in elevation. If you wish to remedy
this, use the following table to correct your reading for sea level.
Your Multiply absorbed
Altitude volume by...
Sea Level 0.0000
1,000 ft. 0.9706
2,000 ft. 0.9411
3,000 ft. 0.9160
4,000 ft. 0.8866
5,000 ft. 0.8613
10,000 ft. 0.7395
15,000 ft. 0.6203
In one of my tests a 750cc absorber displaced 2425cc water at 2,000
feet. Corrected to sea level, that's 2,282cc water displacement. For that particular
absorber, there was an actual capacity of 304% of it's advertised rating, more than I
The rest of this page is an excerpt from:
Use of Oxygen Absorbers in Dry Pack
Research paper by:
Albert E. Purcell
Theodore C. Barber
John Hal Johnson
At the Benson Quality Assurance Laboratory
Department of Food Science and Nutrition
Brigham Young University, Provo, Utah
Oxygen absorbing packets are effective in reducing oxygen contents in sealed
cans. The ageless Z300 packet has a greater than claimed capacity for absorbing oxygen.
Packets abused by 4 hour-exposure-to-air still exceed claimed capacity. It may be
economical to use smaller packets based on the dead air volume instead of can volume.
Smaller packets would have less tolerance for abuse and personnel would need to be more
diligent in protecting the packets.
The level of oxygen remaining in the presence of the absorber packets is
sufficiently low to greatly retard development of rancidity. The biological consequences
are not so easy to predict. Microorganisms range from aerobic to anaerobic, thus no
unqualified statement can be made. The energy requirements of anaerobic bacteria are met
by reactions between oxygen and more than one other molecule. This makes bacterial energy
a higher order of reaction than rancidity. Thus, the rate of bacterial aerobic reaction
would be more seriously retarded than rancidity. These matters are not of practical
importance because the products to be canned should be too dry to support microbial
growth. Insects are aerobic and would like-wise suffer retardation of activity. No
comprehensive statement can be made about irreversible inactivation or death of insects.
As long as the oxygen level remains low, insect activity will be lower by at least the
square root of oxygen content. In a practical sense, these packets are effective in
stopping insect activity. USDA does not recognize any method except disintegration as
effective for completely killing insect eggs.
Table 1: Key to Table 2
Blank Air sealed in a #10 can (No product)
Fresh Air + Fresh packet (Exposed less than 5 min)
X Air + Exposed packet (Exposed 4 hours)
O Product sealed in can with no packet
Milk O Dried Milk only
Milk Fresh Dried Milk + Fresh packet
Milk X Dried Milk + Exposed Packet
Mac O Macaroni Only
Mac Fresh Macaroni + Fresh packet
Mac X Macaroni + Exposed Packet
(Exact measurements couldn't be duplicated in subsequent tests)
Table 2: OXYGEN AND NITROGEN CONTENT OF
SAMPLES AT THREE DIFFERENT TIMES
% of O2 | % of N2
--------- | ---------
48 1 2 | 48 1 2
Sample hours week weeks | hours week weeks
Fresh 0.70 0.42 0.43 | 98.36 98.65 98.65
X 2.27 0.40 0.90 | 98.74 98.67 98.55
Mac O 20.05 20.18 19.98 | 79.11 78.81 79.19
Mac X 0.42 0.42 0.42 | 98.64 98.20 98.66
Mac Fresh 0.45 0.41 0.41 | 98.63 98.66 98.65
Milk O 20.33 19.99 20.14 | 78.72 79.02 78.99
Milk X 0.50 0.43 0.27 | 98.57 98.63 98.62
Milk Fresh 0.48 0.44 0.43 | 98.59 98.63 99.27