Every household has the same moment, eventually. You open the fridge, see a tray of eggs, and can't quite remember when you bought them. The carton has a date that may or may not be the lay date. You're about to make breakfast for your family. Are these eggs still safe to eat, or are they about to ruin your morning?
This article is the answer. Five tests, all of them genuinely reliable, none of them requiring anything more exotic than a glass of water and your senses. Two minutes of work, and you'll know with high confidence whether the egg is fresh, old-but-fine, or one to throw away. We've ordered them roughly by accuracy, with the most decisive test first.
The single most useful thing to know about an egg is when it was laid, not when it expires. Freshness is a continuum, not a binary.
Test 1: The water float test
Water float test
Fill a tall glass or bowl with cold water. Gently place the egg in. Observe what happens over the next 30 seconds.
This is the classic test, and it's the most reliable single check you can do. The reason it works is straightforward: every eggshell is slightly porous, so over time, a small amount of moisture evaporates from inside the egg, replaced by air. The air cell at the wider end of the egg grows larger as the egg ages. A larger air cell means more buoyancy. A very fresh egg has almost no air cell and sinks dead flat; a moderately old egg has enough air to stand it upright; a bad egg has enough air (and gases from bacterial decomposition) to float.
Importantly, an egg that stands upright but stays submerged is not bad. It's older — perhaps two to three weeks old — but still perfectly safe to eat, especially if you cook it well. Older eggs are actually preferred for some applications, like hard-boiling, because the slightly larger air cell makes them peel more easily. Only outright floaters should be discarded.
Test 2: The smell test
Smell test
Crack the egg into a clean, empty bowl (not directly into your dish, just in case). Put your nose close.
If an egg passes the float test but you're still unsure, the smell test is your backstop. A bad egg announces itself. The hydrogen sulphide gases produced by bacterial decomposition are unmistakable — anyone who has ever encountered a truly rotten egg remembers the smell forever. Trust your nose. If something smells wrong, discard. The cost of throwing out a perfectly good egg is a few rupees; the cost of eating a bad one can be a day in bed.
One nuance: a fresh egg has a very faint, almost neutral odour. If you've never paid attention to what a fresh egg smells like, do the smell test on a definitely-fresh egg first to calibrate your nose.
Test 3: The yolk dome test
Yolk dome test
Crack the egg onto a flat plate (not into a deep bowl) and look at the side profile.
This is the test bakers and chefs rely on, because it tells you not just whether the egg is safe but whether it's worth using in a recipe that depends on egg structure. A truly fresh egg has a domed yolk that holds its shape and a thick, almost gelatinous white that stays close to the yolk rather than spreading across the plate. As an egg ages, the proteins in both the yolk and the white start to break down. The yolk membrane weakens (so it flattens or breaks easily), and the white becomes watery.
For making meringues, soufflés, or perfect poached eggs, freshness matters enormously and this test will tell you. For scrambled eggs or omelettes, an older-but-safe egg works just as well as a fresh one.
Test 4: The candling test
Candling test
In a dark room, hold a bright torch against the wider end of the egg. Look through the egg at the air cell.
"Candling" is the technique commercial egg graders use, named because in the old days they actually held eggs up to a candle flame. The principle is the same with a modern torch or smartphone flashlight: light passes through the shell and reveals the size of the air cell at the wider end, plus any internal abnormalities (blood spots, cracks, embryonic development).
This is a great test for the curious, but it's not the easiest. You need a genuinely dark room, a strong directional light, and some practice to interpret what you're seeing. We do this for every Sahya Agro egg before packing — that's why we say "candled by Sunita's team" on the packaging. For home use, this test is more advanced than the others.
Test 5: The shell check
Shell check
Before any other test, look at and feel the eggshell carefully.
This is the simplest test of all but easily forgotten. A slimy or sticky shell is a bad sign — it usually indicates bacterial growth on the surface that has come from inside the egg. Chalky white residue or visible mould means the egg has been stored badly and may have absorbed moisture. Visible cracks on the shell create entry points for bacteria; a freshly cracked but otherwise good egg is fine to use immediately, but cracked eggs that have been sitting for days should be discarded.
Note: a slightly dull, matte shell is actually a sign of a good unwashed egg with its protective bloom intact. Glossy commercial eggs have usually been washed (which removes the bloom and shortens shelf life). We don't wash our eggs — the dullness is a feature, not a flaw.
Float test first. If it sinks flat, almost certainly fine — no further tests needed. If it stands upright, it's older but probably fine — cook well. If it floats, discard. Only crack into a bowl if you need to use it in a recipe that depends on freshness, in which case run tests 2 and 3 to confirm.
How long do fresh eggs actually last?
Stored properly (refrigerated at 4-8°C, in the original carton, in a stable part of the fridge — not the door), eggs are safe to eat for far longer than most people assume. Properly stored unwashed eggs can stay safe for 4-5 weeks from the lay date; washed commercial eggs are typically rated for 21-28 days. Indian regulations are conservative; the actual food-safety window is generally longer.
What changes over time is quality, not safety. A two-week-old egg is just as safe as a two-day-old egg if both have been refrigerated correctly. The two-week-old egg will simply have a flatter yolk, looser white, and a slightly larger air cell. For everyday cooking, you can't tell the difference.
The "best before" date is conservative
The "best before" date on commercial egg packaging is, in most cases, conservatively set 21-28 days from the pack date. Many eggs sold in Indian supermarkets have a pack date several days after lay date, so the on-shelf date might be two weeks past lay. By the time you eat the egg, it might be three weeks old — and still completely fine.
The opposite mistake is also common: throwing out an egg the day after the printed date. The float test is far more accurate than the printed date. Eggs don't suddenly become unsafe at midnight on day 28. They gradually become older, and at some point they cross from "fine" to "iffy" to "definitely no." Your senses can detect this transition long before any printed date pretends to.