Food preservation

Food preservation is important, but it's also a complex topic. There are a ton of different ways to keep your food from spoiling. This guide will broadly cover a few big ones.

Freezing

This one's easy. If you have a freezer that's plugged into a power grid, or if it's below freezing, you can just leave items in the cold and they'll freeze. Items that are frozen do not spoil.

Refrigeration

If you can set up a power grid and get a refrigerator running, items stored in it will be cooled down to 37 F (2.7 C) and go bad much more slowly.

Refer to comments on item::calc_hourly_rotpoints_at_temp:

* Calculate how much food rots per hour, based on 3600 rot/hour at 65 F (18.3 C).
* Rate of rot doubles every 16 F (~8.8888 C) increase in temperature
* Rate of rot halves every 16 F decrease in temperature
* Rot maxes out at 105 F [40.6 F]
* Rot stops below 32 F (0C) and above 145 F (63 C)

Basements: the Poor Man's Fridge

As mentioned above, the rate of rotting decreases with temperature. Basements are at 43 F (6.1 C) all the time, which is a bit warmer than a fridge, but will still help quite a bit compared to leaving food outside during the summer (on the other hand, it will prevent food from freezing during the winter).

Zipper bags and Condiment Bottles

Zipper bags make items go bad about at 80% of the normal rate. This isn't a lot, but it can save a sandwich or two, and it stacks with other methods listed here. Liquids stored in condiment bottles spoil at half the normal rate (food inside sealed ones don't spoil at all, but you can't craft those).

Smoking

The most significant thing you can do to boost the shelf life of your food is to build a smoking rack via the construction menu. At the time of this writing it only takes 3 fabrication, 2 food preparation, and some sticks and rocks. You'll want a charcoal kiln as well so you can keep it fueled up.

To use the smoking rack, examine it, fill it with charcoal, insert your food, and once it's all ready to go, light it up and walk away. In several hours, the food inside will be smoked, vastly improving their shelf-life.

Most smoked items can go through the process again, becoming dehydrated. This preserves them for much longer.

Canning

Canning is done via the crafting menu, and will generally require a canning pot. Many items can be canned, including vegetables, meat, soups, and a bunch of other stuff. Food inside a sealed can will not spoil.

Jerky

Jerky is one of the lamest ways to preserve meat, only adding a couple of weeks to its shelf-life, but it's also the easiest. All you need is 3 food handling, a chunk of meat, some salt, soy sauce, seasoned salt, or pepper, and a way to cook food - even a campfire will do the job.

Vacuum Packing

Somewhere between canning and making jerky, food in a vacuum sealed plastic bag will not spoil in version 0.G and earlier (as of 0.H, vacuum sealed plastic bags only reduce spoilage to half the normal rate). Requires a (makeshift) vacuum sealer to craft.

Rendering Fat

Something most of us don't do in our day to day lives, but that was very important to our ancestors, is rendering fat. Well, society's gone, so we're back to basics.

Fat can be rendered by crafting it into tallow or lard. Tallow and lard are more or less interchangeable, but the tallow recipe is more efficient. Lard on the other hand will produce cracklins as a byproduct, which are basically fried bits of skin and fat that are pretty tasty and can stand in for meat in several recipes.

Tallow and lard have a very long shelf-life and are useful in a ton of different crafts, not all of which are food. One of their most important uses is as a component of pemmican, which is one of the most convenient and long-lasting food items you can make.

If you are cooking mutant meat, make sure you don't eat any of the fat, as it tends to have a much higher concentration of toxins than the other parts.