Oxygen Absorbers: What the cc Number Means

The short version: The cc number on an oxygen absorber is its oxygen-absorbing capacity in cubic centimetres, not a measure of how much food it covers [1][3][4]. You size it against the air left in the sealed container, not the weight of what you put in [10][11]. Use one packet sized up rather than two packets combined, and expect the published charts to disagree with each other by a wide margin.

What cc measures

Impak states the unit plainly: "Oxygen is measured in cubic centimeters (cc)" [2]. Utah State University Extension defines it as "cubic centimeters as it relates to amount of oxygen absorbing capacity" [3]. Dry & Dry says the size "corresponds to the amount of oxygen absorbed" [1].

Three things follow from that definition, and each one is stated by a manufacturer rather than inferred:

• The number is about oxygen, not food. PackFreshUSA: the cc rating is "how much oxygen the absorber can remove, not how much food it protects" [4].
• The number is a floor. Impak treats the rating as a minimum - a 500cc packet should absorb at least 500cc [5]. PackFreshUSA claims its high-capacity packets absorb "180% - 300% of their rating" [30]; OxyFree claims 300cc units measured "1106cc of actual absorption" [16]; AGM says O-Buster packets "pick up approximately three times their weight in oxygen" [9]. Those three claims use three different units and cannot be compared to each other.
• The unit converts cleanly. Wallaby: "1 cc = 1 ml; 1000ml = 1 Liter; 3.78 Liters = 1 gallon" [7]. PackFreshUSA: "oxygen, as a gas, is measured in cc's, and containers are typically measured in milliliters, (ml) but conveniently, 1 ml = 1 cc" [6].

One counter-current exists. Impak alleges that some suppliers label packets by the total air volume they will treat rather than by oxygen capacity, so that "what is a 500cc packet is actually a 100cc packet" - its own testing of one supplier's S-100 units returned roughly 300cc [5]. If a chart's numbers look five times larger than everyone else's, that labelling convention is one explanation.

Why air volume, not food weight

Impak's worked five-gallon example is the clearest published arithmetic in the set: an 18,942cc pail holding 15,876g of rice leaves 3,066cc of residual air, and "3,066 (cc) residual air volume x .21 (oxygen fraction in air) = 628.53 cc oxygen" - rounded up to a 750cc packet [2].

The rule the arithmetic encodes is stated by three separate suppliers. Impak: "The size of oxygen absorber you need depends on the volume of air in the package into which it is placed" [10]. Wallaby: "Each bag size holds a different amount of air, so the absorber must match that volume" [11]. Wallaby again, on why weight fails: sizing must use "the container's residual air volume" [29].

Two complications sit inside that residual figure.

Void space counts, and particle size does not change it. Impak counts "the spaces in between" the product alongside the headspace [2]. PackFreshUSA's version is the most quoted line in the category: "A pool filled with marbles will have the same interstitial air volume as one filled with basketballs" [6]. That holds for identically shaped, similarly packed particles; freeze-dried food is neither uniform nor rigid, and mixed particle sizes let small pieces fill the gaps between large ones.

Different foods hold different fractions of air. PackFreshUSA publishes a three-class scheme: beans and rice "only have about 35% air volume", flour is about 50%, and freeze-dried, oats and pasta sit around 75% [12][19]. It applies the scheme to its own gallon figure - an empty gallon needs 800cc, but "if you were to fill the container with flour (which is about 50% air) then there should be 400cc's of oxygen in the filled gallon container" [6]. This is the only source in the scan that publishes an explicit freeze-dried percentage.

One source dissents from the whole method. Oxygen-Absorbers.com sizes by food weight - 1 kg of rice to 100cc, 2-3 kg to 200cc, 5 kg to 500cc, 10 kg to 1000cc - with no container volume in the calculation at all [18]. PackFreshUSA's "not how much food it protects" line is a direct rebuttal of that method [4].

The multiplier itself is not settled either. Published oxygen fractions of air across this scan are 21.0% [2], 21% [6][8][12], about 20.95% [8], 20.5% [5] and 20% [9]. Two suppliers contradict themselves across their own documents.

The sizing table

Every cell below is that source's own published number for that container. A blank means the source publishes nothing for it. Read across a row before you read down a column.

Impak also publishes a chart indexed by flat bag dimension rather than container: 20cc / 50cc for a 6" x 6" bag, 50cc / 100cc at 8" x 8", 100cc / 200cc at 10" x 14", 150cc / 300cc at 10" x 16", 500cc / 1000cc at 16" x 18", 750cc / 1500cc at 18" x 28" and 20" x 24", and 1000cc / 2000cc at 20" x 30" [13]. Its two columns are "Fine Grains (sugar, flour, etc.)" and "Pasta and Thicker, less Dense Foods" - it publishes no freeze-dried class [13].

Where they disagree, and why the spread is not noise:

• One gallon spans 8x. 100cc [9] to 800cc [6]. PackFreshUSA explicitly labels the 300cc answer a myth [12], while USU Extension [3], O-Busters [9], Discount Mylar [8] and OxyFree [15] all publish exactly that number.
• Five gallons spans 67% between two of the more careful sources alone. USU Extension publishes 1500cc [3]; Dry & Dry publishes 2500cc [1]. Impak's 750cc is not a container rating at all - it is conditioned on 35 lb of rice already occupying the pail [2], and comparing it to a 2000cc bucket recommendation is an error.
• One quart splits a single supplier internally. PackFreshUSA's own math says 200cc, its own product ships 300cc, and it reconciles the two by stating that "200cc worth of oxygen absorbers are actually enough for a quart container, but as our quart bags can hold more than a quart, we use 300ccs in our Mylar sets" [6]. Nominal bag labels are not measured internal volumes.
• Harvest Right's 700cc is the outlier with the thinnest condition. The only qualifier published is "For use in gallon-size Mylar bags" - no food class, no fill level [17] - and it comes from the dominant home freeze-dryer OEM.
• The columns are not the same variable. O-Busters indexes by void-space percentage, not food type, and publishes only "under 10%" and "25% or more" - there is no middle band to interpolate [9]. Impak and Wallaby index by food density [13][7]. PackFreshUSA indexes by air-volume class [12].

Two of these sources disclaim their own charts. Impak: "This Chart represents approximate cc sizes and should not be taken as a final authority" [13]. Wallaby: the chart holds "only the average amount of oxygen absorbers needed" and "you may need more or a smaller number" [7]. No source in this scan presents its chart as authoritative, and a single canonical chart would contradict all of them.

One, never two

The practice statements are consistent. Wallaby: "Drop one absorber into each bag right before sealing" [11]. PackFreshUSA: "If you're unsure, use one slightly larger absorber - not doubling up" [4]. Discount Mylar directs one 2000cc packet into a five-gallon bucket rather than splitting the load [8].

What no manufacturer in this scan publishes is a reason. The rule appears only as practice; searches for a stated mechanism returned nothing. And three sources go the other way: Oxygen-Absorbers.com says "For bags over 5 kg, consider using two smaller absorbers to ensure even oxygen removal" [18]; PackFreshUSA elsewhere suggests buying 100cc or 200cc packets because "These are more easily used and add more as needed" [12]; Wallaby's own bucket chart is expressed as 20 to 30 packets of 100cc [7]. Both PackFreshUSA and Wallaby therefore contradict themselves between documents.

What is not in dispute is the direction of the error to make. Four sources state that surplus capacity is harmless: "Not only is it okay to use more absorbing power than necessary, it is a great idea" [6]; "There is no disadvantage to adding a greater number of oxygen absorbers packets than needed. It won't spoil your food" [7]; "Excess absorbers are harmless - they simply won't fully react" [8]; "There is no danger in adding too many as this does not affect the food" [1]. Undersizing has no equivalent safety margin.

One boundary applies to all of it: absorbers are for dry goods. Wallaby states that foods above 10% moisture, such as brown rice and beef jerky, do not benefit [29], and Discount Mylar's calculations assume food below 10% moisture [8].

Handling and the indicator

Absorbers begin working on contact with air, and the published working window varies by an order of magnitude: 10 minutes [19], 10-15 minutes [14], 10-20 minutes [8], 15 minutes [3], 15-30 minutes [1], 30 minutes [18], 20 minutes to start with ruin in as little as 5 hours [19], and up to 90 minutes for a slow-acting product [16]. Harvest Right publishes no number at all - only "Once opened, oxygen absorbers begin working immediately" [17]. Dry & Dry says saturation takes 2-4 hours while still recommending a 15-30 minute window [1], contradicting its own stated physics.

Two packaging formats exist to shorten the exposure rather than the clock. PackFreshUSA sells individually sealed packets so you can "open one at a time, reducing exposure, waste and the need to reseal" [30], and compartment packs of 5 or 10 [21]. Wallaby packages "in sets of ten to preserve effectiveness until use" [14]. For loose packets, PackFreshUSA's instruction is that "Unused oxygen absorbers may be stored in a mason jar or vacuum sealed" [6].

The colour indicator is less definitive than it looks:

Purple carries two incompatible meanings across sources [5][20]. PackFreshUSA's own position is that the indicator is not the better test - a live absorber should "feel like fine powder" rather than hard and crunchy [20].

As for the end state, published residual oxygen figures are 0.1% or lower from Mitsubishi Gas Chemical [23], approximately 0.01% from Impak [27], and below 0.01% from PackFreshUSA [21] and Harvest Right [17]. The company that originated the technology publishes the least aggressive number.

Vacuum sealing is not oxygen-free

A vacuum sealer reduces the volume of gas in the bag. It does not change what that gas is made of - the residual is still about a fifth oxygen. PackFreshUSA states it directly: "Air still contains oxygen - even after vacuuming" [4]. Wallaby reframes the step as preparation rather than treatment: "This is not vacuum sealing; you're simply removing large pockets so the absorber will have less work to do" [11].

NC State Extension is the source to read twice on that last row. Reduced-oxygen packaging is pathogen-selective, not sterile, and "these disease-causing bacteria may not change the color or look of the food" [28]. Sealing does not reclassify a food: "Perishable foods that need to be refrigerated or frozen without vacuum packaging still need to be refrigerated or frozen once sealed" [28], and "vacuum packaging is not a substitution for the heat processing of home canned foods" [28]. Discount Mylar states the same boundary from the supply side - absorbers are for dry goods [8].

What we could not source

• A cc figure for freeze-dried berries, or any specific freeze-dried food. No manufacturer in this scan publishes one. The closest published structures are PackFreshUSA's 75%-air class [12] and Discount Mylar's "bulky/freeze-dried = 500cc" per gallon [8].
• A freeze-dried class in most sizing charts. Impak's chart stops at "Pasta and Thicker, less Dense Foods" [13]; Wallaby's stops at "Less Dense Foods (beans, pasta)" [7]; O-Busters has no food classes at all [9]. Harvest Right, a freeze-dryer OEM, publishes no freeze-dried-specific cc [17].
• Any mechanism behind the one-absorber rule. Repeated searches for a manufacturer explaining why packets should not be split returned practice statements only [11][4] - no stated reason.
• A 20.9% oxygen figure. No manufacturer in this scan publishes it. The published values are 21%, 21.0%, 20.95%, 20.5% and 20% [2][6][8][5][9].
• Any exposure-time figure from Impak / Sorbent Systems, the most technically detailed supplier in the set. None appears in any document retrieved [2][5][13].
• A regulator document naming oxygen absorber packets. A GRAS claim exists as a manufacturer assertion [19]; searching for a corresponding FDA document returned nothing, so we do not repeat the claim as established.
• An oxygen-concentration threshold for the Ageless Eye colour change. Mitsubishi publishes the colour direction but no percentage [22].
• Cc capacities from Multisorb or the English-language Mitsubishi Ageless pages. Type names and applications are published; capacities and selection math are not [23].
• Non-ferrous absorbers above 100cc. The maximum published non-ferrous size is 100cc, so gallon and bucket volumes have no non-iron option in this scan [27].
• Peer-reviewed literature on absorber performance. The one review located was inaccessible, so no independent test evidence sits behind any capacity claim here.
• Measured internal volumes for common mylar bag sizes. PackFreshUSA's admission that its quart bags hold more than a quart [6] implies nominal labels are unreliable across the category, and nobody publishes measured figures.

Sublime Pantry has not bench-tested any absorber, bag, or food. Everything above is what the manufacturers and extension services publish, with their disagreements left visible rather than averaged away.

Next

• Six beliefs the manufacturers contradict — the sizing folklore this page keeps meeting.
• Storage containers compared — the vessel the absorber is sized for.
• When stored food fails — what an undersized or exposed absorber looks like later.

Sold by Sublime Pantry: 100cc Oxygen Absorber Refill — one cc size sold on its own: 100cc, which pairs with a pint bag and smaller.