May 072012

Two cans, side by side, of the same product in the store, one with more than twice the shelf life of the other

Nothing lasts forever – least of all, alas, ourselves.  But, if we can ignore that most relevant of all issues (at least for now), let’s instead look at how long any food item will last, and how can we give it maximum longevity.

In a very simplified form, the life of any food item varies depending on a number of different factors.  Some types of food are more sensitive to some storage issues, others are less sensitive, and of course, some types of food start off with only short shelf lives and little chance of extending them, whereas other food items are inherently long-lived and can be extended considerably further.

It seems that the current ‘state of the art’ for extended shelf life products is expressed in the commonly found freeze-dried foods that offer the promise of a 25 year shelf life.  Is this realistic?  Ask us in twenty-something years!

Not to get ahead of the article, but even a tin of freeze-dried product with a 25 year shelf life claim can have a longer or shorter life depending on a number of facts as to how it is stored.  Of course, the tin of product has been designed to control many of those factors just by nature of it being a sealed tin, but others still apply.

So let’s consider the major factors as they relate to any and all food products and the shelf life you can expect from them :

  • Bio-activity (ie fresh fruit or meat going ‘rotten’, seed germinating, etc)
  • Water/moisture – (Both humidity and liquid water can trigger or accelerate bio-activity)
  • Oxygen (and sometimes other gases too)
  • Light (although some things may be activated also by the lack of light)
  • External contamination/pests/etc
  • Temperature (usually the cooler the better)

The one reliable constant factor that can be said in all cases is that the warmer the temperature an item is stored at, the more rapidly it will spoil, whereas the cooler the temperature, the longer it will last.

Having said that, there are practical limits to how cold you should chill items down to.  Sometimes it is not a good thing to freeze items – the freezing of the moisture inside the item may break up the item’s cells, making it go mushy when unfrozen.  But in most cases, keeping an item down around 40° or thereabouts will appreciably extend the life of the item in question.

How to Tell if Food is Still Good or Bad?

The words ‘good’ and ‘bad’ need quote marks around them in the heading, because they are subjective measures rather than absolute measures.  And they can have several different meanings.

One measure of bad food is when an item has become unhealthy to eat – when it has acquired a significant level of harmful bacteria or toxins such as to make a person eating the food item unwell.  Even this is not an absolute measure, because some people have stronger stomachs than others.

Another measure is when a food item no longer looks attractive or smells appealing.  These of course are subjective measures too, and it is fair to say that what looks unappealing to a person in middle class suburban comfort today might look extremely appealing to a starving person post TEOTWAWKI tomorrow.

Our sense of ‘bad’ food is a fairly reliable predictor of safe/unsafe food.  If food looks and smells bad, and if you proceed to taste it and it tastes bad too, it probably is bad.

Yet another measure is when the nutritional value of the food item has reduced down to something close to zero.  This is impossible to detect by looking/smelling/tasting; but you’ll find out empirically.  If after eating a food item for several days, your weight goes down and health deteriorates, probably the food has lost most of its nutritional value.

MREs as an Interesting Example of Time vs Temperature

Just exactly how much extra storage life can you expect by keeping your stores cooler than you otherwise would?  There’s no exact answer to that question, but a couple of elaborate tests of MREs give us some clues.

Testing of the MRE formulation in the 1980s (which included free-dried food items) by the Army’s Natick laboratory were conducted, using a panel of ‘average’ people, and having them do subjective taste testing, with the results then averaged to try and create some consistent measures.

These taste tests showed that the shelf life of MREs ranged from as short as one month if the MREs were stored at 120° to as long as 130 months if the MREs were stored at 60°.

The report said that longer shelf life would be possible at temperatures below 60°, but the test did not have the time to study this.  It also said that food which was rejected by the panelists as unappealing was still nutritious and healthy, even though it no longer looked, smelled or tasted appealing.

Here’s a table showing the results.

Storage Life
months increase
(from previous row)
% increase
(from previous row)
120 1 n/a n/a
110 5 4 400%
100 22 17 340%
90 55 33 150%
80 76 21 40%
70 100 24 30%
60 130 30 30%


The key learning point here is not so much the increase in shelf life between 120° and 110°, but more relevantly, the increase in shelf life between 70° (the temperature are houses are at, most of the time) and 60°.

The implication of this is that we can increase the shelf life of many products that we store by a sizeable amount – 30%, which in many cases will mean another year or more of shelf life – by doing nothing more complicated than keeping them in the coolest part of the house.  That closet in your basement, rather than upstairs in the sunny pantry.

After the reformulation of MREs, a new set of tests was run.  The results aren’t directly mappable to the other set of results, and show the new MREs have much shorter shelf lives.  Here’s the best guess we can make on the new results to show them in similar format to the old ones

Storage Life
months increase
(from previous row)
% increase
(from previous row)
120 1 n/a n/a
110 2.5 1.5 150%
100 6 3.5 140%
90 18 12 200%
80 36 18 100%
70 40 4 10%
60 48 8 20%
50 60 12 25%


These results are interesting because they add another data point – the additional extension in shelf life at 50° rather than at 60°.

The earlier set of results showed a 30% shelf life extension by going from 70° down to 60°; this newer set shows a lower 20% extension, with a further 25% extension if dropping the temperature by another 10°.  While not quite as drastic as the earlier set of results, 20% is still better than nothing, and probably for no more effort than moving your stores from one part of your house to another, and in the possible event that this cool area averages closer to 50° than 60°, you’re getting as much as 45% extra life compared to leaving them in the warmer part of your house.

Here’s a good page with some interesting pictures of applesauce and cheese spread (click them to see more) that has been stored at different temperatures and times.

Why the Variation in Shelf Life Extensions?

You’ll see there is no constant variation in shelf life extensions per ten degrees of temperature change – either in terms of months or percentages.  This is slightly puzzling because most chemical reactions speed up at a constant rate related to temperature increases, and so we would normally expect to see steady percentage changes.

There are two factors at issue here for why some ten degree steps have larger or smaller impacts on shelf life than others.

The first is sampling and testing errors.  There is no scientific exact way of rating food as good or bad based on appearance and taste, so the personal preferences of the samplers will add an element of randomness to the numbers.  We’d suggest all numbers be viewed as plus or minus 10% of reality, which enables us to say, for example in the second set of results ‘10% plus a 10% sampling error is within the same zone as 25% less a 10% sampling error’.

The second is that different processes are triggered at different temperature points.  Some processes might be dormant at all temperatures below a certain number, but ‘wake up’ and start impacting on shelf life above a certain point.

What Does the Shelf Life Statement on a Food Item Mean?

So there you are, looking at your can of baked beans, and studying the ‘Best By’ date printed on it.  How was that determined, and what happens the day after this date?

The USDA has a page that explains some of the distinctions between ‘Use By’, ‘Sell By’, and ‘Best By’ dates.  Some of what they say is vague and meaningless, and the key take-away point is that these dates for non-perishable food items (ie not raw meat, fruit, etc) are not very exact or scientific.

We suspect – but absolutely don’t know for sure – that some food manufacturers find themselves steering a compromise path between setting dates that are too ridiculously short (which might discourage people from buying their products) and dates which are extended well into the future (which would reduce the amount of food people either junk or eat in a rush due to it being about to expire, and which also could create liability if the food is not well stored).

The significance of the date you see is not actually the date itself, but how far into the future it is.  If we say that, to be on the safe side, manufacturers assume a storage temperature of 80°, and you actually store the item at 50°, then this could be enough to give you an extra 65% of storage life.  So if the date shows you have two years remaining when you buy the item, maybe that means you really have, in your cooler store, an equivalent of just over three years.

Plus also remember that these dates are when the food first starts to become less than prime/perfect.  There’s an unknown amount of extra time into the future before it becomes appreciably less than appealing.

Pure Seed and Grain Storage – More Temperature Dependent

Here is an excellent page of information about storing grains and seeds, including rice and wheat.  It cites the USDA in claiming that a 10.1°F change in temperature will halve or double the shelf life of the product being stored (depending on if the temperature goes up or down).

The two main points from this page are to keep items cool and oxygen free, and that whole wheat keeps a lot longer than flour, and white rice much longer than brown – you probably already knew these things, and now you’ll understand why, too.

These rates of change are much greater than observed with the MREs.  We guess this may be because the MREs have been treated to give them some longevity so the usual ‘laws’ of biological activity and their dependence on temperature have been modified.

Special Case :  Medicines

Very good news here.  The expiry dates on medicines are ridiculously conservative.  With the exception of insulin, liquid suspension antibiotics and nitroglycerin, most medications can be considered to remain active and potent for ten years beyond their expiration dates.

Again, the same as other items, the cooler you keep them, the longer they’ll last.

Useful Tip :  Check Shelf Life in the Store Before Buying

You probably know, when buying milk or other products with a short shelf life, it pays to check the expiry date before selecting the product in the store.  Sometimes you’ll note a carton several back from the one in front might have a week or more of extra shelf life – ie, the milk cartons in front offer one week, and the ones behind them offer two weeks.  If you’re not sure how long the carton of milk will last you, it for sure makes sense to take one from the back of the line.

Surprisingly, this is true of other items too.  We were in a local supermarket today and observed cans of tomatoes on sale.  Tomatoes – an acidic product – typically have a shorter shelf life.  Some of the cans were showing an expiry of March 2013 (ie 10 months from now) but some of them were showing an expiry of March 2014 (ie 22 months from now – more than twice as long).

And if we were to store them in a cool place, getting perhaps a 50% extension in shelf life as a result, that would get us an extra 18 months of storage time on the longer dated product.

This was an astonishing difference in shelf life statements.  So if you’re buying even canned goods that you won’t be immediately opening and eating, be sure to check the shelf life statements on the cans, and choose your cans accordingly.


Shelf life statements on food items you purchase are not exact magical dates whereby the food is perfect up until midnight on that date, and then useless/dangerous from that point forwards.  If anything, these dates represent the shortest amount of life you can expect from food items, not the longest.

Shelf life of all items is massively influenced by temperature.  A change of 10° may as much as double (or halve) the shelf life of food items; there will be less impact on pre-processed items, more impact on unprocessed items.

Always keep everything as cool as possible, but most products should be kept slightly above freezing point.

Apr 292012

The Fifth Annual ‘Rich States, Poor States’ report has just been published

Where should your retreat be based?

There are lots of issues to consider in answering that question, and depending on the respective importance people give to the different factors to be considered, you will see a group of people, all given the same raw facts, come to completely different decisions with no two people reaching the same conclusion.

One factor to consider is the economic health of the state you are choosing to live in ‘normally’ and/or choosing to retreat to if all goes wrong in the future.

The good sense in living in an economically prosperous state in ordinary normal times is obvious.  But we suggest that even after ‘the end of the world as we know it’ you’ll still be better off in a state that was, until that time, prosperous.

In general, prosperous states interfere less with their citizens, and their citizens in turn are content to enjoy their own good lifestyles without obsessing too much if their neighbors have it better than them or not.  Prosperous states, by definition, tend to have more people employed and fewer people on benefits, and if you had to choose between having people on state benefits or successful fully employed people living in your area, you’d probably prefer the latter.

Prosperous states also tend to have lower rates of crime, probably because more people are working and getting a good living honestly.

We’re not saying this is the most important factor by any means when choosing locations, but it is one of the many factors to consider, and we mention it now due to the release of the fifth annual ranking of states in terms of their economic outlooks.  This study – ‘Rich States, Poor States’ and published by the American Legislative Exchange Council lists the ten best states as being :

1  Utah

2  South Dakota

3  Virginia

4  Wyoming

5  Idaho

6  Colorado

7  North Dakota

8  Tennessee

9  Missouri

10  Florida

And the ten worst states?  They are :

41  Pennsylvania

42  Rhode Island

43  Oregon

44  Illinois

45  New Jersey

46  Hawaii

47  California

48  Maine

49  Vermont

50  New York

The entire 125 page report can be downloaded from ALEC’s site for free.  It includes detailed analyses of each state’s economic condition and policies, and lots more information too.

Apr 292012

The timeless nature of the Cessna 182 is shown in this 2009 picture of a 1956 model – ie, when it was already 53 years old.

One of the big challenges we must consider and confront is how we would manage to get from our normal residences to our retreats if/when a major disaster is about to occur (or has already occurred).

The ideal choice is, of course, to simply hop into the family car and drive there normally.  But doing this would only be possible if you were able to anticipate any such disasters and get all the way to your retreat some hours before anyone else started to react the same way, and before the roads started to clog up with vehicles and become a giant solid unmoving parking lot.

In the best case scenario, you could do this; indeed not just in best case scenarios but also in more generally anticipated scenarios too.  We discuss the likelihood of traffic congestion interfering with your ‘bug out’ activities here.

Nonetheless, as a prudent prepper, you need to consider not only reasonable scenarios but unreasonable scenarios too.  And planes can be useful not just for avoiding road congestion, but for other reasons too.

Planes Are Useful Alternatives for Many Reasons

A plane can of course get you anywhere quicker than any vehicle can.

A plane can allow you to delay your decision to bug out, because you don’t need to be so concerned about beating the traffic.  Sometimes it can be advantageous to delay a decision as long as prudent, and if you have a plane as a transportation option, you have more time up your sleeve.

A plane gives you another route to where you’re going.  Maybe the roads are closed due to bad weather or as a side effect of the situation that triggered the crisis.  An earthquake, for example, might have caused bridges to fall, a volcano erupting might destroy roads with molten lava runs.

Weather issues may have a much greater impact on travel by road in a Level 2 or 3 scenario.  For example, if a road is washed out, it may not be repaired again.  Or, if a heavy snowfall occurs, there might be no snow removal crews and no snow removal equipment to clear the road, causing it to remain closed all winter long.

While planes are also weather dependent to an extent, the type of weather issues that affect them are short-term rather than potentially 3+ months in duration, and they give you a second chance in the game and more ways to get from where you were to where you want to be.

Most planes don’t have more range than a car with lots of additional gas tanks, but their speed means that what might be a two or three day journey by car can be done comfortably in a single day in a plane, with just one take-off and one landing.

Because plane travel is not dependent on roads, you never run the situation of ‘you can’t get there from here’ – you simply fly directly, the shortest way you wish, between any two points, whereas the roads underneath you might meander around and detour through dog-leg loops, adding hundreds of miles to your journey.

Planes travel is also safer – you’re not going to get speeding tickets or otherwise hassled, whether by law enforcement or other drivers and onlookers while flying through the air.

Flying to Your Retreat In Your Own Airplane

We offer this suggestion completely seriously.  If you live not a long way from a general aviation airport (ie one where private planes can be stored, and where they fly in and out), and if the budget allows it, consider buying a private plane.

A plane as a bug-out-vehicle has the huge advantage that it is not likely to suffer congested roadways.  On the other hand, it relies upon some infrastructure being in place both where it will depart from and where it will land and provides a somewhat weather-dependent means of transportation.

It also has limitations in terms of how many people and how much cargo it can carry (assuming you get a small single engined plane) – although maybe you can ferry people and materials to your retreat in two or three journeys if you can’t fit everything you must get into the plane for a single flight.

Even Better – a Float Plane

Maybe both your normal residence and your retreat is closer to a lake than to an airport (or to a sheltered bay in the ocean).  In such a case, a float plane is better than a regular plane, because whereas airports can experience problems (for example an earthquake which rips up the runway), and may even be operating under emergency air traffic control restrictions that impede private flying, lakes have no such problems at all.

Float planes are more weather dependent, and also become more limited to daylight hours of operation only, so there are trade-offs to consider and evaluate.

Airport/Lake Location Doesn’t Matter for Your Retreat So Much

Note also that the most important issue is the proximity of a suitable lake or airport to your normal location.  It doesn’t matter nearly as much at your retreat.  This is because we are assuming it may be very difficult to travel from your home to the airport or lake where the plane takes off from, but it will probably be comparatively easy to travel on from where you land to your final retreat, due to it being in a low density rural location where the roads are unlikely to be jammed full of people urgently trying to get out of town.

It is much more practical to plan to drive the last 5 or 10, or even 50 or 100 miles to your retreat once you’ve got out of and away from the major population centers.  You need to take to the air to get out of the cities, but once you’re in a rural setting, you can more comfortably plan to complete your journey with relatively few problems by some type of automobile.

Note also the Code Green Halfway House – maybe your objective is merely to fly to the Code Green Halfway House, at which point you can then retrieve a backup vehicle, freshen up, and complete your journey the next day.

Time is Money – Speed is Survival

If you are driving by car to your retreat, you’ll be traveling at the same speed as everyone else who is also evacuating the city you live in.  You’ll be potentially at risk from the people in the cars all around you every minute of your journey, and they’ll be ‘with you’ every part of the way.  And when you finally arrive at your retreat, you might find some unwelcome and uninvited strangers have already got there before you!

But a plane gives you two huge advantages.  The first advantage is that you’re flying at 120 – 180 mph rather than driving at anything from 0 – 70 mph, depending on traffic.  The second is that you’re traveling quite literally ‘as the crow flies’ – in a straight line, the shortest route possible.  These advantage combine to help you get where you’re going massively more quickly, and apart from the vulnerabilities getting to the city airport you fly out of, the rest of the way is comparatively safe.

The Cost of a Plane

Planes are not as expensive as you might think.  While you can certainly spend over a million dollars for a plane, older planes can be had for as little as $50,000.

A 30 – 40 year old single engine Cessna 172, capable of carrying four people (ie a pilot plus three others) and a little freight (depending on passenger weights and how much fuel is loaded) up to 850 miles on a full 56 gallon tank of gas, while cruising at 140 mph can probably be purchased for something in the range of $50,000 – $75,000.  Newer, larger, faster planes, and with more range, of course go up in price, but you can still get something good for $100,000 or less.

Airplanes are subject to strict maintenance, inspection and certification requirements, and are also flown many fewer hours each year than a car is driven.  You can buy an older plane with much more confidence than you would an older car.

You’d of course need to get a private pilot’s license, and you might want other family members to get one too in case you’re incapacitated, and for more overall operational flexibility.  Learning to fly is more complicated than learning to drive, of course, but 80+ year old grandmothers have learned to fly, as have 15 year old teenagers, and every type of person in between.

Spread the Cost More Ways

Consider getting another couple to buy into the plane with you.  A four seater plane can hold four people, after all, and one of the key things you want to do is to have more people in or adjacent to your retreat than just yourself.  There is safety in numbers, and if those same numbers can also reduce the cost of buying and maintaining a plane, so much the better.

Operational Considerations

You need a plane and you need somewhere secure to store it at your home airport or lake.  You need a private pilot’s license.

You’ll want to keep the plane fully fueled, and if you might be ferrying passengers and supplies on multiple flights, you’ll want a supply of fuel at your destination and possibly top-up fuel at your home base as well (depending on how far the plane must fly for each roundtrip).

You’ll also need a vehicle and somewhere secure to store it at the place you’ll be flying to.

Most airplane engines run on a special type of ‘av gas’ but some planes and their engines can be adapted to run on regular automobile gasoline.  If you had your plane modified for regular auto gasoline, it would be more versatile and easier to refuel in the future.

Although you’d want to make use of the latest GPS and avionics, be sure you can navigate without GPS because many worst case scenarios involve the loss of GPS service.

Read More On This Topic

This article has proved popular, and we’ve now added a second article with much more information – More on Planes as Bug-Out Vehicles.