food-storage-shelf-life

Temperature Versus Food Storage Shelf Life

Temperature is the most important factor having to do with general food storage shelf life. Here’s how it relates…

There are temperature versus food-storage shelf life statements and charts around the internet, some of which are in error (I have made this same mistake). Having recently read about accelerated shelf life testing by companies who do this, I have discovered the flaw which others have made with regards to the relationship between temperature and food storage shelf life. That is, degrees Celsius versus degrees Fahrenheit.

Many have stated and charted that for every 10 degrees (F) of increased temperature, the shelf life will halve. For every 10 degrees of cooler storage temperature, the shelf life will double.

The problem with that is the actual formula used to calculate this relationship is referenced in degrees Celsius, not Fahrenheit!

Two correct ways to state the general relationship are as follows:

For every 10 degrees C, shelf life will halve or double (hotter-cooler).
For every 18 degrees F, shelf life will halve or double (hotter-cooler).

There are caveats which will affect the exact ratio, but the general statement is accurate based on the Q10 temperature coefficient and the Rule of 10.

Q10 Rule-of-10 Temperature vs. Shelf Life

The temperature coefficient (Q10) represents the factor by which the rate (R) of a reaction increases for every 10-degree rise in temperature (T).

Q10=[R2/R1]^[10/(T2-T1)]

T1: Hypothetical Storage Temperature (C)
T2: Room Temperature Constant (22 C)
R1: Rate Reference of the rated shelf life (# days, weeks, months, years, etc.)
R2: Rate to solve for (will be same unit as R1)
Q10: 2 (doubling)

Examples

(rounded to nearest decimal)

degrees-Celsius
A can of food with a rated shelf life of 1 year (at room temperature 22 degrees C) will actually reduce to one-half year if stored at 32 degrees C.

degrees-Fahrenheit
A can of food with a rated shelf life of 1 year (at room temperature 72 degrees F) will actually reduce to one-half year if stored at 90 degrees F.

Formula for the example above:

T1: 32-degree-C storage temperature
T2: 22-degree-C room temperature constant
R1: 1 year rated shelf life
R2: ?

2=[R2/1]^[10/(22-32)]
solve for R2
R2=0.5

If we store the same can of food in a cooler environment, the inverse is true…

degrees-Celsius
A can of food with a rated shelf life of 1 year (at room temperature 22 degrees C) will actually increase to 2 years if stored at 12 degrees C.

degrees-Fahrenheit
A can of food with a rated shelf life of 1 year (at room temperature 72 degrees F) will actually increase to 2 years if stored at 54 degrees F.

Formula for the example above:

T1: 32-degree-C storage temperature
T2: 12-degree-C room temperature constant
R1: 1 year rated shelf life
R2: ?

2=[R2/1]^[10/(22-12)]
solve for R2
R2=2

More Examples

Let’s say some of your #10 cans of long-term survival food is stated to have a shelf life of 10 years. By keeping them downstairs in the basement which may be 65-degrees, in theory you’ll get 13 years shelf life.

Another example is when you’re storing some food (cans, food bars, etc.) in a 72-hour kit which is inside your vehicle during the hot summer. Something with a given shelf life of 1 year while stored in a 100-degree-F car will be reduced to 17 weeks (slightly more than 3 months).

The basic lesson here is that you can potentially significantly increase your food storage shelf life by storing in a very cool environment while at the same time you can severely harm food storage shelf life in a hot environment.

The lower the temperature, the better.

The higher the temperature, the worse.

Use-By and Sell-By dates

Sources:
Q10 temperature coefficient calculator
Metric conversions
MOCON shelf life studies

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17 Comments

  1. These rules are generally true, but are not true in every case. Instead of saying “shelf life” it should say something like “More/less heat affects the food as if it had been cooked longer/shorter, which usually decreases/increases shelf life.”

    The reason this is important is because some manufactures (of canned pinto beans, stew, and similar foods) under cook their product in order to save money, so what would degrade most foods actually improves others, at least to a certain extent.

  2. Great information and article. Hopefully this will stop people from storing food in uninsulated sheds and attics.
    Love your site and often link to it.

  3. So storing chopped clams in a shed outside in Death Valley is probably not the best idea….

  4. Can boxed cereal, cookies, boxed cracker and chips be stored in a room that reaches 100degrees?

    1. Yes, but it won’t last as long.

      Without getting out my calculator – shelf life (e.g. ‘use-by’ date) might be reduced by more than half at that temp. So simply consume it before then…

      If the manufacturer’s posted shelf life or ‘use-by’ date was attributed for room temperature, 72-F, then 90-F storage conditions would theoretically halve the shelf life expectancy. 108-F would halve it again…

  5. What if your storage area goes below freezing ? Does the comment “cooler the better” still apply?

    1. Tony
      Are you referring to external freezing or internal freezing?

      If your storage room is above ground and the temperature drops below freezing per a thermometer in that building wet food contents will freeze inside of any cans that you have in that storage area.

      The best temperatures for storage are around 50 degrees but no more than 70 degrees. Over 70 degrees will begin the slow breakdown of the food stored in your storage area. In other words the shelf life will drop, not that the food will sudden be bad for consuming.
      Any other thoughts you have on food storage, just ask, this group has many years of knowledge.

      I had a case of Dennison’s chill with meat that went 3 years after it’s best by date in temperatures from 20 degrees to over 100+ degrees during that time. It was still good but as time went on into the 3rd year I could tell by taste that the meat was getting old

    2. – Tony – If the temps inside your wet-pack canned good drops below freezing, you may run into a problem with the water freezing and expanding. I mean, I don’t care if you want to add antifreeze to the inside of your canned goods, but… LOLOL
      The problem is the cans can rupture, which kinda makes it difficult to declare it safe to keep on keeping. Usually, you don’t have issues with above ground storage until the temperature gets several degrees below freezing, but it will stress the seams and shorten the shelf life.
      – Papa S.

      1. – The temps inside a B.O.B or G.H.B. kept inside a hot car can be reduced by keeping the foodstuffs inside a cooler box or bag, and it in turn being kept out of direct sunlight (a cardboard box, a blanket, usually the more disreputable looking the better, LOL). I try to keep the majority in a cooler bag under the back seat to protect it from both heat and sun. it is still reduced but not as severely as if you don’t do those things.
        – Papa S

  6. Does the temperature need to be constant in your storage area during the course of a year ? I pre-ordered some variety meal storage buckets from a company but then started reading a prepping book. The book said basically that variations in the storage temp will cause moisture leading to earlier spoilage. I was planning on storing in my basement where the temps probably vary from 45 in the winter to 70 in the summer. I don’t think I have a place to store where the temps wont vary. Upstairs (like a closet) my temps will always be above 70. My buckets wont come until July or later and I’m thinking of cancelling. Any thoughts ? Thanks.

    1. NewPrepper;
      Under the house is not a bad place to go.
      The variance between Winter and Summer is a lot better that full time at a higher temp.
      Also most Long Term is well suited for 70deg or lower.
      The moisture build up should not happen if your buying form a reputable Co.

      PS: I have some of my storage in the Craw Space, zero problems for well over 8 years.

    2. @NewPrepper,
      Here’s my opinion:

      If the temperature change is gradual, there really should be no issue. Sounds like you have a great temperature range for long term storage (less than “room temp” for a good part of the year is great).

      You might consider placing the bucket storage on a board (or whatever else) rather than directly on the concrete.

    3. New Prepper,
      Good Job,It is a beginning will be looking forward to your posts and questions.
      It is a beginning for you and who ever you choose to shelter.. Now the hard part… getting things to go with those ‘survival buckets” to stretch them…Storing where temps are 45 much of the winter and up to 70 is not the very worst… some of the higher temperatures can be mitigated if you place insulating things around them… DO NOT cancel that order.!. You will need that and much more for a long winter. ( already some areas of the country are seeing weather changes that will prevent growth/production of crops- temps above 105, with Uv index above 10., flooding, areas unable to plant, soil saturated, etc).. . DO NOT tell anyone else you have food coming and where it is located..Operational security is the term…OPSEC, for short. Any one you “happen to mention” it to may tell others and you have chosen an amount for your family…Food for a month for your family will be reduced- the more people come to your door and demand to be fed… so best to just avoid the crisis by not mentioning you are storing food.
      All companies sell food by servings, those serving sizes may not match your families needs… if a rice based meal can add more rice to it, instant rice adds easily..
      Pasta can be added to pasta based meals and canned meats can be added for nutrition and satiety.
      Do not forget to stock things like oil , flour.,cornmeal..( those need to be sealed/oven canned. for longest life and rotated out..)whole wheat can be ground for flour or soaked and used for cereal or sprouted for greens…It stores indefinitely when kept cool/dry.( bucket)… things for making gravy and biscuits,
      Not all foods will appeal to all families. be sure to test a few of those selections to make sure your family will eat them. If you find a selection needs more spices/additions of something make a note of the name of the entre’ and what needs to be done to make it to YOUR family’s liking…

  7. Thanks for the quick response, folks ! That’s good news. I probably would never have thought about emergency food if not for the pandemic. I’m hoping we are headed out of this one but who knows now about next year and the year after. Again, thanks for your views and the quick turn-around.

    1. NewPrepper;
      Tis better to have a few items than to watch the Kids starve.
      I do believe that if you hang around here for some time you’ll see there is a LOT of good information.
      And no I don’t believe there are any of those Doomsday Preppers here.
      Just a lot of people that live a Lifestyle of comfort of knowing one can outlast most problems. AND it’s actually fun having the knowledge of doing, not just buying.

    2. NewPrepper;
      One other thing, It’s not the Pandemic most are worried about, tis the crashing economy.

      Lastly, a lot of folks here have been doing this a very long time, please if you have questions, feel free to ask.

      This is one of the very best sites for “true” information, basically because if someone tries to “lay a line of BS” out there, someone will correct them to be sure.

      Ok, one more “Lastly” please learn some skills also, be it Gardening, Self-defense, Canning, preserving foods, whatever. Food storage is only the first little step in living a Lifestyle whereas you can actually “make it” in bad times.

      Welcome to Ken’s Blog….

  8. The article references MOCON shelf life studies, but without a link. Where can we find those shelf life studies. I searched for “MOCON shelf life studies” and didn’t find anything useful.

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