To determine how many CC’s (cubic centimeters) your oxygen absorber should be when packing food for long-term storage (5 – 30 years) it’s important to consider the type of food being packed, as requirements will vary depending on the volume of your food and the space (air) in between each morsel. Our biggest concerns are what we refer to as “void space,” or the amount of space between food particles, and the “head space,” or the amount of space in your container that has not been filled with food.
As an example, if you packed a 5 gallon bucket all the way to the top with marbles leaving no head space, the void space is the amount of air between each marble. Because marbles don’t pack as densely as, say, salt, your bucket would require a larger CC oxygen absorber to account for that extra air.
For the mathematically inclined, the general formula to determine the specific amount of cubic centimeters of oxygen absorption required is as follows:
Container Volume – Food Volume = Residual Air Volume
Residual Air Volume x 0.21 (because air is made up of 21% oxygen) = Oxygen Absorber Size Requirement
We want our oxygen abosrber to meet or exceed the residual air volume in the packed container.
Practical Application: If you are packing 35 pounds of rice into a 5 gallon bucket we first need to determine the amount of CC’s for the rice. You can utilize an online calculator to determine that 35 pounds of rice is equivalent to 15,875 cubic centimeters (cc’s). Our 5 gallon bucket is equivalent to 18,942 cc’s of air volume.
Assuming our 35 pounds of rice fills the bucket to the top leaving no head space, we can calculate our void space (Oxygen Absorber Size Requirement) as follows:
18,942 cc (Container Volume) – 15,875 cc (Food Volume) = 3,067 cc (Residual Air Volume)
3,067 (Residual Air Volume) X 0.21 (Oxygen) = 644 cc (Oxygen Absorber Size Requirement)
The following chart is a general guide based on the type of food you may be packing. Since we can’t expect to calculate our head space and void space exactly, when in doubt we should err on the side of caution and utilize a larger CC oxygen absorber.
The chart belows assumes that the container has been fully packed and as much excess air as possible has been removed. Vacuum sealing is recommended when available. Because oxygen absorbers are often sold in 50 cc, 100 cc, 300 cc, 500 cc, 1000 cc and 1500 cc the figures below are not exact and have been estimated upwards.
| Food Item | One Quart Pouch(8″ x 8″ bag)(947 CC’s) | # 10 Can(0.82 Gallons)(3,910 CC’s) | 5 Gallon Bucket(18,942 CC’s) | 6 Gallon Bucket(22,730 CC’s) |
| Flour / Pancake Mix / Fine Powders | 50 cc – 100 cc | 200 cc – 300 cc | 750 cc | 1000 cc |
| Sugar / Salt / Dry Milk | 50 cc – 100 cc | 200 cc – 300 cc | 750 cc | 1000 cc |
| Rice, Grains (Wheat Berries, Oats) | 50 cc – 100 cc | 200 cc – 300 cc | 750 cc – 1000 cc | 1000 cc – 1500 cc |
| Beans | 100 cc – 150 cc | 300 cc – 500 cc | 1000 cc | 1500 cc |
| Pastas | 100 cc – 200 cc | 300 cc – 600 cc | 1000 cc – 1500 cc | 1500 cc – 2000 cc |
Unless I’m misunderstanding something here, #10 can (.82 gal) should be 3788cc*.82=3106cc
new dry canner here….how about using canning jars and giving the number for pints, qts, gallons etc for the number of oxygen absorbers.
thanks!