Foraging

The Universal Edibility Test — rub it on your skin, touch it to your lip, hold it on your tongue, wait, swallow a little, wait eight hours — is printed in survival manuals and is still repeated in most survival courses. It does not work, and the ways it fails are the ways that kill.

• Amatoxins (death cap, destroying angel, funeral bell) produce no reaction for 6 to 24 hours. The test's whole waiting period elapses inside the latent phase. A taster passes, eats a full meal, and dies of liver failure four days later.
• Orellanine (deadly webcap) has a latent period of two to three weeks before the kidneys fail. No test of any duration a person would actually sit through can detect it.
• Cardiac glycosides (foxglove, oleander, lily of the valley) act on the heart at doses far below anything that irritates a lip or a tongue.
• Cumulative toxins — the pyrrolizidine alkaloids in comfrey and ragwort, for instance — do nothing measurable in one sitting and damage the liver over weeks of small doses.

The test also assumes you have eight hours and nothing better to do, which in the situation that produced the question is rarely true.

The rule that replaces it is short: you eat what you can name. Not what looks like something you can name. Not what a chart resembles. Species, with the feature that separates it from its look-alike, checked on the specimen in your hand. If you cannot do that, it is not food — it is fuel for a fire you are not going to light with it either.

Foraging fails groups not because they cannot find plants but because they spend the day finding the wrong ones. Salad is not an energy source. The wild foods that pay are fats and starches: nuts, acorns, and a few underground storage organs.

The table is the whole argument. Read the last column first.

This is not a complete list of poisonous species — that list runs to thousands. These are the ones that account for most deaths in temperate regions, because they are common, they are found near people, and each one is mistaken for something edible.

Read the tell on each card. It is the single feature that separates that species from the thing it is confused with, and it is the feature to check on the specimen in your hand — not the general impression.

Apiaceae contains carrot, parsnip, celery, parsley, fennel, dill, coriander and caraway. It also contains hemlock, water hemlock and fool's parsley. They are all green plants with finely divided leaves, hollow ridged stems and flat white umbels, and in the field, at speed, they look the same.

This family kills more foragers of plants than any other, and the reason is that the reward looks so ordinary. A wild carrot is a small, tough, white carrot. It is not worth the risk profile, and that judgement — the payoff is not worth the identification burden — is the correct one far more often than foraging literature admits.

If you are going to eat a wild umbellifer at all, all four checks must pass on the same plant:

1. Stem hairs. Wild carrot is distinctly hairy. Hemlock is hairless. "Queen Anne has hairy legs" is a mnemonic worth keeping.
2. Purple blotching. Any purple mottling or streaking on a hairless stem means hemlock until proven otherwise. Stop there.
3. Smell. Crush a leaf. Wild carrot and parsnip smell of carrot and parsnip. Hemlock smells mousy, musty, unpleasant.
4. The root, cut lengthwise. Solid and pale in wild carrot. Chambered, with yellow oily sap, in water hemlock.

Fail any one of the four and the plant goes back on the ground. There is no partial credit here.

Mushrooms are near the bottom of the calorie table and at the top of the risk table, which makes them a poor survival food and an excellent food once you actually know a few. The way to learn them is not to memorise a hundred species; it is to learn five that have a clear, checkable difference from their dangerous double, and refuse everything else.

Each card below names that difference. Where the difference is a cut rather than a look, make the cut.

Acorns fed populations across North America, Iberia, Italy, Turkey, Korea and Japan for thousands of years. A single mature oak drops 25–90 kg in a good year, the crop stores for years if it is dried, and shelled acorn is about 390 kcal per 100 g — real carbohydrate, not salad.

The obstacle is tannin: 2–10% of dry weight depending on species. It is astringent, it blocks protein absorption, and in quantity it damages the kidneys. It is also water-soluble, which is the entire solution.

The procedure:

1. Collect after the first heavy drop, usually after the first frosts. Discard any with holes (weevils), any that float in water, and any with mould.
2. Dry them in shell for a few days near a fire or in the sun until the caps and shells come away easily. At this point they store for a year or more.
3. Shell and remove the papery skin. Break the kernels into coarse pieces — the smaller the pieces, the faster the tannin leaves, and the more starch you lose with it.
4. Leach. Two methods, and they are not interchangeable:
   • Cold leaching. Grind to a coarse meal, put it in a cloth bag in a stream or in a pot with several water changes a day. Takes 1 to 7 days depending on species. It is slow and it is the better method, because the starch keeps its binding properties and the meal will make dough and bread.
   • Hot leaching. Boil the pieces in water, pour the water off when it colours, and refill with already-boiling water. Five to ten changes of 10–15 minutes. Takes an hour or two. Faster, but the starch gelatinises and the resulting meal will not bind — use it as porridge or gruel.
5. Test by taste. Take a pinch. Astringency — the mouth-drying, puckering sensation, which is a feel and not a flavour — means keep going. When it tastes bland and faintly sweet, it is done.
6. Dry the leached meal before storing, or it moulds within days.

Rough yield: 1 kg of whole acorns → about 500 g shelled → about 400 g of usable meal.

A number of wild and semi-wild foods are staples in one preparation and poisons in another. The distinction is never visible and rarely tasteable.

This is a starting point that admits it is one. It is written for temperate Europe and North America, and it covers perhaps forty species out of the thousands you could meet.

It is not a field guide and it cannot replace one. Identification from photographs alone — including the photographs above — is how people get hurt, because a photograph shows one specimen at one age in one light, and the features that matter are often on the underside, inside, or below ground.

What actually works:

• A regional field guide, in print, for the place you are standing. Regional matters more than comprehensive: a guide to the wrong continent is worse than none, because it gives you confidence about the wrong look-alikes.
• A person who already knows. Fungi in particular are learned in the field over seasons, not from books. Every mycological society runs forays and most are free.
• A short list, learned properly. Ten species you can identify cold, in any condition, beats a hundred you half-recognise. Add one species a season and you will out-forage someone who memorised a chart.

The charts on this page are drawn illustrations. They are for range and vocabulary — for learning that a category exists — and they are not identification. Nothing on this site asks you to decide eat or do not eat from a drawing.