Float the egg, then smell it

It is old. Whether it is bad is a separate question, and people spent a good deal of their argument getting that straight. Many people use the water test: fresh eggs sink and lie flat, older ones tilt or stand on end, and eggs that float are old. People in some other discussions explain why, and some people turn it into the rule that matters: the shell is porous, moisture leaves through it over the weeks, the air pocket inside grows, and eventually the egg is light enough to float — so floating measures age, not spoilage. An egg that floats can be perfectly fine inside; an egg that sinks can, rarely, not be. People argue ‘floating means throw it out’ against ‘floating means old — smell it’ (one person says the first, many people the second), and the decider, as people put it, is what food-safety guidance says: age and spoilage are different things. Other discussions have the same argument, with many people saying the strict rule wastes fewer worries and some people saying it wastes eggs — people’s decider is whether you would rather never smell a bad egg or never throw a good one away. The float test is not a safety test on its own. Some people put it the same way. One person points out the middle case: an egg standing on its end is ageing and is fine for baking, and only an egg that rises fast to the surface is one to be suspicious of. Others add the edges: all eggs have some air, so the test is never absolute; very dark-shelled eggs may float less readily at the same age because the thick pigment slows the moisture loss; one person had mixed results with it altogether; and one person has never met a bad egg in fifty-seven years, and another never in a shop-bought pack. The line this page keeps repeating comes from one person: because the shell is porous, water from the test can carry bacteria from the outside in — use a tested egg straight away.

Crack it and smell it — many people say that is the whole test — with the one blind spot named above. Many people say the definitive check is to crack the egg into a separate bowl and give it a sniff: the foul, sulphurous smell of a spoiled one is something that they say you cannot mistake and one person says you would not get past. Others say smell and sight are the only reliable checks: a bad egg may also look wrong — discoloured or blackened patches, and one person adds a runny, watery white or coloured bits — and one person adds that if it does not smell bad, it is very probably fine. Others give the other checks: shine a light through the shell to see the air pocket or a crack, which one person says takes practice to read; and the old idea that a fresh egg spreads less when cracked and an old one more, which people argue over — one person with experience raising hens says breed, diet and hydration change the spread more than age does. One person says, for what it is worth, that they have never once cracked a bad egg from a shop carton. What the smell test cannot do is above this page: salmonella does not smell, so for anyone vulnerable the answer is to cook the egg through, not to sniff it. What a spoiled egg looks like beyond the smell is a question people asked more than once and did not fully answer.

It means the shop had to sell it by then, mostly — and one line differs by country. Some people say the dates on a carton mark peak quality or when the shop should have sold them, not the day the eggs become unsafe, and individual people spell out the ladder: ‘sell by’ is very forgiving, ‘best before’ somewhat, and ‘use by’ is the one that sits close to the real limit. One person warns that in the UK a ‘use by’ date is a safety date and should not be crossed, unlike ‘best before’ — so read which words are on your box. One person with the US rules says a carton can already be up to two months old when you buy it, because the rules allow thirty days between laying and packing and another thirty for sale — a ceiling this page checked against the US Department of Agriculture’s rules and found right; the same guidance says eggs keep three to five weeks in the fridge after you buy them. Some people say the date confusion is why so much food goes in the bin, and one person says eggs keep better than almost any other food. Some people add the case with no date at all: eggs straight from a farm or a neighbour are usually excellent and occasionally very bad, which is exactly why the float and the smell exist. How the labels differ in countries other than the US and the UK is a gap people named.

It depends which country’s eggs they are, and people from both sides agree on the reason even where they argue about the rest. Some discussions and a run of individual people lay out the split. In the US, commercial eggs are washed by law before sale, which strips the natural coating on the shell — the bloom, or cuticle — and leaves the shell more porous, so they must be refrigerated and kept cold. In the UK and much of Europe, eggs are not washed, the coating stays, and hens under the UK egg-industry scheme are vaccinated against salmonella, so eggs are sold unrefrigerated and kept at room temperature in many a kitchen for weeks; one person there has done it for a long time without incident. This page checked both halves against US and UK guidance and both hold, with one addition: UK food-safety guidance permits room temperature but recommends a cool place or the fridge. Some people argue across the split — on whether eggs must be refrigerated at all, on whether an unwashed egg is safer or merely longer-lasting, and on whether to wash eggs from your own hens — and people’s decider is where you are and what has been done to the shell — and, for your own hens’ eggs, how long you keep them and how much risk you accept. The competing statistics people trade about which country has more salmonella are not printed here: they are contested and this page ranks neither country. Some people add a trick for making unwashed eggs last: a thin coat of food-safe mineral oil seals the shell, and one person uses petroleum jelly. For the fridge itself, one person says the back, the coldest part, not the door, and under about forty degrees Fahrenheit US eggs keep about five weeks; one person warns the number on the fridge dial is not the temperature inside it. Exactly what temperature, and what to do in a hot climate with no fridge, are gaps people named — and if you are in the US, the room-temperature line is not for you.

Almost always — and people name the two exceptions honestly. Some people make the first point: cooking kills bacteria, but it does not always destroy the toxins some bacteria leave behind, so an egg that has genuinely spoiled is not rescued by boiling it. People argue whether that risk is real for an egg that passed the float and smelled fine; it is not settled, and people’s decider is whether the particular spoilage bacteria make a heat-stable toxin and whether it soaks into the egg — a question people raise and cannot answer. The second exception is above this page: salmonella has no smell, so for an infant, someone ill or someone elderly, one person here and the public guidance say the same thing — cook the egg until the white and yolk are firm, and do not rely on a nose. For everyone else, what people corrected and warned about adds up to this: sinks and smells fine, use it any way you like; floats and smells fine, it is old, not bad — one person warns it will not taste fresh and suits baking, and some people say an older egg peels more easily boiled; smells wrong, bin it. Some people add the one advantage of an older egg: it peels far more easily once hard-boiled, so the eggs that stood on end are the ones for the egg salad. How long an egg stays safe once it has floated, and how long a cracked-open egg keeps, are two more gaps people named. The meat and milk that came up follow different rules — one person warns meat wants far more caution than an egg — and are not this page.