Long-term food storage: what keeps for years, and why

Four things decide: moisture, oxygen, heat, light

Dry food doesn’t go off overnight the way milk does. It loses quality slowly, and four things set the speed. The first is the one every source puts at the top: for long-term storage, the food has to be dry, about 10% moisture or less, in the words of both the Church of Jesus Christ of Latter-day Saints and Utah State University (USU) Extension.¹³

Heat is where the numbers move fastest. The USDA’s figures for military ready meals show the slope: 7 years at 16 °C (60 °F), 4½ years at 21 °C (70 °F), 18 months at 38 °C (100 °F) and one month at 49 °C (120 °F).¹¹ In BYU research that USU cites, wheat stored hot, in a garage or attic, kept an acceptable quality for only 5 years.⁴ Even USU gives two ranges for the ideal: 4–16 °C on its wheat page and in a 2015 column, 4–21 °C (40–70 °F) on its storage-conditions page.⁶⁴ Germany’s environment agency, the UBA, puts it in household terms: dark, aired, dry and cool, at most 18 °C, away from the cooker, the oven and the fridge.¹⁸

Which staples keep longest, and under what conditions

The Church’s advice is to build a longer-term store around wheat, rice, pasta, oats, beans and potatoes, packed properly and kept cool and dry.² How long each keeps depends on whom you ask.

The columns differ by decades because they answer different questions. The Church’s chart gives “Life-Sustaining” shelf lives: how long the food stays edible, not how long it stays at its best.¹ The USDA’s times are for quality on a kitchen shelf, and the BLE’s are a rule for a household that eats its stock. Milk powder shows it most clearly: 20 years for the Church, 15 in the BYU table the Church links to, 3–5 years cool for USU.¹¹⁰⁷ Dried pinto beans get 30 years from the Church, and none of the other three gives a figure.

What the long figures leave out matters as much. The Church keeps nuts, brown rice, wholewheat flour, dried meat such as jerky, dried eggs, granola and chocolate out of long-term storage altogether.¹ USU says dried whole milk isn’t suitable because of its milk fat,⁷ and BYU counts cooking oil and peanut butter as short-term foods of a year or more.¹⁰

Mylar, oxygen absorbers, buckets: what each is for

Foil pouches, sold as Mylar-type bags, are the oxygen barrier. The Church describes its own as laminated plastic and aluminium, 178 microns thick (7 mils), and says the metal layer is what keeps moisture and oxygen out. It also says they aren’t rodent-proof.¹

Oxygen absorbers are small sachets of iron powder, salt and activated carbon or clay; the iron binds the oxygen in the sealed pack and turns to iron oxide.¹⁵ They aren’t silica gel and don’t dry the food.¹⁶ Low oxygen kills the insects in the food and slows the loss of quality, says the Church.¹ USU adds that wheat doesn’t need to be kept without oxygen unless insects are present, and that bay leaves, nails or salt have “absolutely no effect” on them.⁶ Tox Info Suisse, the Swiss poison centre, says sachets found in a pack are not to be opened but thrown away, and kept from children and pets.¹⁶

Buckets and PETE bottles are the outer layer. The Church uses PETE bottles for wheat, corn and beans, and for up to five years for white rice, and plastic buckets “under certain conditions” for dry foods unlikely to go rancid.¹ USU warns that polyethylene bags and 5-gallon (about 19 litre) food-grade buckets won’t stay oxygen-free after an absorber has done its work.⁶

How to read a very long date

USU draws the line plainly: the date on a pack is the “best if used by” date, when you still get most of the original taste and nutrition, while a “life sustaining” shelf life is how long the food stays edible.³ EU and British labels work the same way: best before is about quality, use by about safety.¹³¹⁴ A promise from a maker is a third kind again. One US maker of emergency meals offers a “30-year taste guarantee”,¹⁷ which is that maker’s promise about taste, for its food and its packs.

Read that way, most decades on a label shrink to a condition: a dry staple, sealed without oxygen, kept at the temperature the source names. Change one of the three and the number no longer applies. For a reserve you rotate rather than bury, the BLE’s one or two years and the dates on the packs are the figures that matter, and a two-week pantry from the supermarket shows how to keep that turning; the foods themselves are in the non-perishable food list.

What we print on the pouch, and why

Every figure above is for dry staples in their own packs. A cooked meal with meat, oil and sauce in it is a different food, so none of those numbers carries over to a pouch of ours. Freeze-drying doesn’t kill bacteria, USU Extension says: it leaves the food too dry for them to grow, and if a damaged pack lets it take up moisture they can become active again.⁹ That’s why an opened pouch has a short time and a sealed one a printed date.

Three of our pouches: weight, shelf life sealed and once opened

Pouch	Net weight	Keeps for	Once opened
Chicken & RiceStandard	110 g	at least 12 months	24 hours
Puchero Broth	60 g	at least 12 months	7 days
Cherimoya	40 g	at least 12 months	7 days

Three of our pouches: weight, shelf life sealed and once opened

• Chicken & RiceStandard

  Net weight

  110 g

  Keeps for

  at least 12 months

  Once opened

  24 hours

• Puchero Broth

  Net weight

  60 g

  Keeps for

  at least 12 months

  Once opened

  7 days

• Cherimoya

  Net weight

  40 g

  Keeps for

  at least 12 months

  Once opened

  7 days

Freeze-drying is one way of drying among several, and what it changes against warm air is in the difference between freeze-dried and dehydrated. How many kilos of all this one person needs for two weeks is a sum of its own: how much emergency food per person.

From our range

Chicken & RiceStandard

Keeps at least 12 months sealed, and 24 hours once open.

€9.90€90.00/kgHear from us before the shop opensSee the meal