Free tool

Oxygen Absorber Calculator

How many cc for a jar, a mylar bag, a #10 can, or a bucket - sized by how densely your food packs, with packet counts you can actually buy.

Per 1-gallon mylar bag:

300 cc of absorber

For all 1: 300 cc total. That is 1 × 300cc or 1 × 500cc packets (rounded up; extra capacity is harmless).

Work fast once the absorber bag is open: packets start absorbing immediately, so seal spares in a small jar or bag within minutes.

Dry foods only - this is the safety rule

Oxygen absorbers belong with foods that are dry (about 10 percent moisture or less) and low in oil: white rice, wheat berries, rolled oats, dried beans, pasta, flour, dried corn, potato flakes. Sealing a moist food in a low-oxygen container at room temperature creates exactly the environment botulism needs - if a food is soft, chewy, or fresh, it does not go in a mylar bag with an absorber. And skip them for sugar and salt entirely: those never spoil from oxygen, and the absorber just cements them into a brick.

Why density changes the size

An absorber has to scrub the oxygen out of the air in the container, and how much air is left depends on how the food packs. Fine, dense foods like rice and flour settle tightly and leave little headspace; irregular shapes like beans, pasta, and freeze-dried meals trap air throughout. That is why the same 1-gallon bag wants 300cc of absorber for rice but 500cc for beans - the widely published home-storage figures this calculator is anchored to. When in doubt, round up: an oversized absorber simply finishes its job early, while an undersized one leaves oxygen behind.

Handle packets like they are perishable

Absorbers start working the moment their pouch is opened - including on the air in your kitchen. Set up every container before opening the pouch, drop the packets in last, seal immediately, and store unused packets in a small airtight jar filled to the brim. A packet that feels hard and crunchy has usually spent itself; fresh ones feel soft and powdery.