The Knowledge: How to Rebuild Our World From Scratch by Lewis Dartnell Read Free Book Online Page B

cracked or ground (which exposes the inner germ to moisture and oxygen), so unmilled whole wheat grains remain good for decades. Likewise, whole corn kernels will remain nutritious for around ten years, but this persistence time drops to only two or three years for cornmeal. Dried rice will keep well for between five and ten years.
    This all assumes that the remnant food will be in conditions favoring preservation: cool and dry. This isn’t an unreasonable expectation for the interior of a large supermarket in temperate regions, but if you’re living in a hot, humid climate, food will begin to decay rapidly as soon as the grid goes down and air conditioners rumble to silence. After the refrigerators and freezers fail, the pungent aroma of putrefying food will attract many nonhuman foragers: rats and insects, as well as packs of dogs and other former pets now growing increasingly hungry. Even well-packaged food is likely to succumb to the onslaught of teeth and claws, so the food resources available to the survivors may be limited less by expiration dates than by pests—no different from the granaries of the earliest civilizations.
    By far the largest reserve of preserved sustenance, however, will be the rows upon rows of canned food that fill the supermarket shelves. The armored packaging will not only resist the post-apocalyptic plagues of vermin and insects, but the heat treatment during the canning process is exceptionally good at protecting their contents against microbial spoilage from within. Although the printed “best before” date is often only two years in the future, many canned products will keep for several decades, if not more than a century after the fall of the civilization that produced them. Rust or dents on the can itself do not necessarily mean that the contents are compromised, as long as it shows no signs of leakage or bulging.
    So if you were a survivor with an entire supermarket all to yourself, for how long could you subsist on its contents? Your best strategy would be to consume perishable goods for the first few weeks, and then turn to the dried pasta and rice, as well as the more resilient tuber vegetables, before finally resorting to the most reliable reserve of canned produce. Assuming also that you are careful to keep a balanced diet with the necessary intake of vitamins and fiber (the health supplements aisle will help you here), your body will need 2,000 to 3,000 calories a day, depending on your size, gender, and how active you are. A single average-size supermarket should be able to sustain you for around 55 years—63 if you eat the canned cat and dog food as well.
    This calculation naturally scales up, from a single individual with a supermarket at his or her disposal to the surviving population of a cataclysm surrounded by the preserved sustenance of a whole nation, from small corner stores to enormous distribution warehouses. For example,the UK Department for Environment, Food and Rural Affairs (DEFRA) estimated in 2010 that Great Britain has a national stock reserve of 11.8 days of “ambient slow-moving groceries” (nonperishable, unfrozen produce such as rice, dried pasta, and canned goods). With an apocalyptic population crash, this would equate to up to fifty years supply for a surviving community of a few tens of thousands of people.Thus a post-apocalyptic community large enough to rapidly reboot technological civilization should have sufficient breathing room to reinstate agriculture and grow its own food.

FUEL
    Another key consumable of modern life, and one that will remain crucial for transport, agriculture, and running generators during the rebuilding, is fuel. There will be huge reserves of gasoline and diesel fuel for the surviving population. The fuel tanks of millions and millions of cars, motorcycles, buses, and trucks offer a scattered repository that can be tapped into. Gasoline can be scavenged from abandoned cars by siphoning it out of the tank, or even more