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

38 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.

  9. I have 5 gallon food buckets with mylar bags and 2000cc oxygen absorbers in each bag. There are 25lbs in each bucket with items like rice, beans, oats.
    They are all over the house and somewhat in the way…..we have a lot. I have my 24ft enclosed trailer in my back yard now. We live in Northwest Arkansas. Winter temperatures generally over the season are lows in the 20s and highs in 40s-60. But last year we had a few days below zero. It would really be nice to be able to shift some of these buckets to the trailer in the back yard.
    Does this scenario sound ok for putting buckets out in the trailer?
    Thanks

    1. Where is the best place to hide stored food. What can you do to avoid having other people or the Govt from trying to take it from you. How can we store outside if we are forced from our homes? Underground?

  10. I live in Phoenix. Average 107 summer, 70 winter. No one has basements here. I’ve had 750 lbs of high quality survival dehydrated food for 15 yrs now. Mountain House.
    I’m sure based on an average storage temperature of 80 degrees, it’s at its end. Edible is different than expiration.
    What now? It was $1500, 15 yrs ago. Must be triple that now for 750 lbs. Just throw it out and buy new? Holy cow…..

    1. Miles
      Years ago, before we had heard of food storage the dh & lived in your section of the country. Yes, it gets hot and well 70 is still shorts & t shirt weather.

    2. Miles – I would hang on to it and surrender same to the “demanding” hungry or government confiscation when SHTF. Use the bad to protect the good. If it’s bad….they won’t be back for more. Ya get what you pay for. Or…..use it for trap bate or animal feed if possible. Critter stomachs can sometimes handle a lot more than we can.

    3. Miles
      Where have you stored such items, will be question #1.
      Were they stored in your house, in a spare room or did you place them in the garage? Believe it or not I have eaten that food we had purchased many years ago in the emergency package. Power was out for 3 or possible 4 days where I reside. I happened to eat those packages you are worried about and believe it or not, they were still good.

    4. Miles……I believe around 2018 mountain house started putting a store below temp level on there packages….it was either 70 or 75. I built a insulated food storage room in my shop with its own thru the wall window a/c…set at 70 which worked great since it never got below 40 in the room during the winter and most items were free dried it worked great. Remember talking with a couple who lived in Arizona who put a couple of thousand dollars of mountainhouse in a tin outside storage shed with temps reaching into the 110 degrees or above range and wondered why it went bad…..we all learn from our mistakes hopefully. Hope this helps

  11. Ok the wife and I went on vacation for a week, the “pantry” has a dehumidifier and AC unit that has kept the storage at 65 degrees and roughly 30% humidity for a few years constant. We got home to find that the AC had shutdown and the dehumidifier was still on and heated the space to around 88 for probably 7-10 days. What if any effect could that have on the items?? The humidity was extremely low and ZERO lighting complete darkness.. mostly all canned meats, and items in 5 gallon buckets.. I’m hoping that it did little in the way of shortening the life too much… please give me your thoughts….

    1. Randy Prepper, In my opinion, nothing at all to worry about, given your description. Too short a period of time to be concerned. That’s only a small fraction of a given estimated product shelf life time frame.

      1. Thanks Ken!! I thought it should be ok but as a prepper I’m already worried about everything else! LOL!! It’s back to cooling down again.. I think that the humidity is more of a factor especially for the canned goods…

        1. Good job on your storage conditions… I recall a number of years ago while transitioning from where we used to live and our eventual current residence – we rented a small house for ~ 2 years. Lots of our food storage was in the basement where it was fairly humid. We did end up losing some cans to rust. My bad…

          1. Ugh! That sucks.. we did do the very same thing too.. now a fully enclosed conditioned space we rarely think about/check…. We are proud of it all… our little food nest egg!

    2. Randy Prepper,
      if only for a week, you should be fine. but maybe look your food storage versus long term power outages.
      good luck. many here have been doing this for a long time, if anyone here can help, let us know.

      1. I do also have enough solar to run the 2 components and then some it was a freak event and actually replaced the AC unit today as it went bad after 9 straight years of running, a little GE 5000 BTU unit gave it up….

        1. May be a blessing in disguise. The AC unit you replace it with will likely have better efficiency and save you some electricity.

          1. It was and this new unit is like 11.4 seer so yes much more efficient the old one was around 10 I believe… thanks!

          2. Randy Prepper – If efficiency is your goal, why not just make the jump to a real mini-split? I use Senville aura systems which provide 22 SEER with air handlers for each room. My neighbors are paying $600+ a month this time of year for central AC using it cautiously. My last bill (yesterday) was $290 to stay as cool as I please PLUS chilling the storage room 24/7.

        2. Randy Prepper – There is a new type of window unit that works as a mini-split. I believe it is Midea that makes it. Think of a saddle turned sideways, that how it fits over your window sill. the evaporator parts hang inside and the condensing portion hangs outside the window. Only a line set and cable runs through the window opening so your window closes and opens, almost as normal without an AC. This is an inverter type and you’ll probably realize 9,000 btu worth of cooling for less than that 5k box cost to run. This is revolutionary tech, you’ll make back your investment in electrical cost savings while staying as cold as you’d like.

          1. YES I saw that a few weeks ago and their not cheap but as you say over the run of it it will be a cheaper energy alternative for sure! I believe the seer was above 14!!!!!! WOW!!

    3. Randy,
      Glad it didn’t go on too long!
      Just curious, if your space is “fully enclosed” does that mean no window for an A/C? If so, what sort of portable unit do you use, or is it part of your whole house A/C?
      My basement storage area is windowless & has an A/C incoming vent, but no exiting return, so with doors closed, the dehumidifier has been mandatory. Not too much of a problem in the summer when I’m cooling the whole house, but once heat is needed in winter, it becomes a challenge to keep cool, even with the incoming vent closed. Wish I’d put in separate A/C units for each floor!

      1. It is literally a closed in and off area in our basement where it’s located like a store walk in cooler sorta.. it does have a window ac unit and dehumidifier inside it with a built in pump, the line is a 1/4 inch and run to our basement floor drain. The window unit is in the wall and the back side is insulation boxed in with a large squirrel cage motor that pulls the hot air off it and forces it out a drier vent I’ve installed, it removes all the generated heat, also a note because it doesn’t get damp inside the space there is no need for a drain for the unit as it never accumulates. The dehumidifier is directly below the ac unit and I have the front panel removed from the ac unit so that the dehumidifier output is piped directly into the condensate coils on the ac unit and that’s set at “Continual” mode to always be removing moisture which does vary from 15% to 50% some days which are rare but I think the concrete basement floor inside the pantry allows it to permeate through… all in all it works great!

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