Packaging freeze-dried food for sale
Freeze-dried food leaves the machine drier than the air around it, and from that moment it’s pulling moisture back in. Packaging decides whether your customer opens a crunchy bag or a sticky one, and for some foods it decides whether the food stays safe.
Why freeze-dried food needs a real barrier
Freeze-drying preserves food by removing water and lowering its water activity, the measure of how much free water microbes can use. Purdue Extension puts the numbers simply: most harmful organisms need a water activity of at least 0.85 to grow, and most unwanted organisms need at least 0.60. The same publication makes the point that matters most to a seller: freeze-drying is not a kill step. Bacteria in the food are preserved along with it, and if moisture gets back in, they can grow again.
That’s why packaging for sale is a moisture problem first. For candy the failure is quality: it goes sticky and loses its crunch. For fruit, vegetables and meals it can become a safety problem too.
Bags
Use a barrier bag: a mylar or foil laminate that blocks moisture, oxygen and light. Clear plastic bags look good on a table, but plain plastic film lets moisture and oxygen through over time, so they’re only for product that will be eaten very soon. A clear window in a mylar bag is a compromise; it shows the candy, and it’s the weakest part of the bag.
- Size the bag to the fill. Extra headspace is extra air to deal with, and a half-empty bag looks short-filled even when the weight is right.
- Seal across the full width with an impulse sealer, and check every seal by pressing on the bag. Every Stay Fresh freeze dryer ships with a 12 in impulse sealer, 50 mylar bags and 50 oxygen absorbers; for more bags, see Mylar bags, 50-pack ($29.99).
- Zip-top bags are worth it for anything the customer won’t finish in one sitting. Heat-seal above the zipper; the zipper alone isn’t a barrier.
- Bag quickly. Package straight from the machine, on a dry day if you can choose, rather than leaving trays out in a humid room.
Oxygen absorbers, and how to size them
An oxygen absorber is a sachet of iron powder that rusts, using up the oxygen in a sealed bag. It protects flavor, color and fats from oxidation over long storage. It doesn’t remove moisture; it isn’t a desiccant, and it can’t rescue food that wasn’t dried completely.
Absorbers are rated by the cubic centimeters of oxygen they can take up. Air is about 21% oxygen, and freeze-dried food is mostly air inside, so the arithmetic is short: estimate how much the sealed bag holds, multiply by 0.21, and round up to the next absorber size.
| Bag holds about | Oxygen inside (× 0.21) | Absorber to use |
|---|---|---|
| 500 ml (small candy bag) | About 105 cc | 100–200 cc |
| 1 quart (950 ml) | About 200 cc | 200–300 cc |
| 1 gallon (3,785 ml) | About 800 cc | 800–1,000 cc, or several smaller |
Absorbers start working the moment their package is opened. Take out only what you’ll use in the next few minutes and reseal the rest in an airtight jar.
Check your state first. A bag with an oxygen absorber in it counts as reduced oxygen packaging, and some cottage food programs don’t allow it. Ohio is one: its cottage food rules permit freeze-dried candy but not cottage foods in reduced oxygen packaging. Our state-by-state guide covers this. Heat-sealing a mylar bag without an absorber is ordinary packaging.
Make sure it’s dry before it’s bagged
No bag fixes under-dried food. Break the thickest piece from the middle of a tray: it should be dry and crisp all the way through, with no cool or chewy center. When a batch is borderline, run it longer; over-drying costs an hour, under-drying costs the batch. If you sell fruit, meals or anything beyond candy, a water activity test from a food lab gives you a number to keep with your batch records, and some regulators will ask for one.
Setting a best-by date
Federal rules don’t require a date on most food, but you’ll want one, and marketplaces like Amazon require them (see where to sell). The long shelf-life claims you see for freeze-dried food describe careful home storage, not a retail bag that’s been carried around a market. Set your own date by testing your own product: seal a few bags from a batch, keep them at room temperature, and open one at intervals to check texture and flavor. Date your bags conservatively inside what you’ve tested, and print a lot code or batch date beside it.
Storing and shipping finished bags
- Keep stock cool, dry and out of the sun. Heat softens freeze-dried candy even in a sealed bag, so shade your table at summer markets.
- Ship in boxes, not envelopes, and fill the empty space. Freeze-dried food is light and fragile, and a crushed bag of dust is a refund.
- Rotate stock: oldest batch out first, and track which lot went where.