Egg Freshness: Why Old Eggs Float and Fresh Eggs Sink (and How to Test Them Right)
You’ve heard it before: old eggs float and fresh eggs sink. That rule is broadly true, but it’s not the whole story. This chef’s guide explains why eggs float over time, how to perform the water test correctly, when the test isn’t enough, the best way to store eggs, and how to choose the right eggs for everything from poaching to pastry.
Table of Contents
1. Why Do Eggs Float as They Age? 2. The Water Float Test: Step by Step 3. Limits of the Float Test 4. Pro-Level Checks You Can Do at Home 5. Smart Storage: Temperature, Position, Hygiene 6. Common Myths (Busted) 7. Food Safety Essentials 8. Which Eggs for Which Recipes? 9. Quick FAQ 10. Book a Private Chef Experience1. Why Do Eggs Float as They Age?
Eggshells are naturally porous. Over days and weeks, water evaporates from the egg while air enters. The internal air cell grows, the egg’s density drops, and older eggs tend to float. Fresh eggs have a tiny air cell and therefore sink and lie flat on the bottom.
Key point Floating reflects age, not guaranteed spoilage. Always inspect smell and appearance after cracking.
How the inside changes
As eggs age, the white becomes thinner and more fluid; the yolk membrane weakens and flattens. Combine those internal signs with the float behavior for a reliable freshness picture.
| Indicator | Very fresh egg | Older egg |
|---|---|---|
| Water test | Sinks, lies flat | Floats partially or fully |
| Egg white | Thick, cohesive | Runny, spreads |
| Yolk | High and centered | Flatter, may drift |
| Smell | Neutral/clean | Off/sulfurous → discard |
2. The Water Float Test: Step by Step
- Use a deep bowl or glass and cold water.
- Gently lower the egg—don’t drop it (to avoid hairline cracks).
- Sinks & lies flat → very fresh.
- Sinks but stands upright → older but usable; cook soon.
- Floats → old; crack into a separate bowl and assess smell/appearance. When in doubt, discard.
Chef tip: After testing, dry the shell and refrigerate. Don’t test with warm water and don’t store eggs once washed (see Storage).
3. Limits of the Float Test
The float test measures relative age, not microbiological safety. An egg can sink and still be unsafe if contaminated; conversely, some floaters may still appear usable when cracked—but treat them cautiously.
- Smell test: any sulfur/rotten note → discard.
- Visual check: unusual cloudy/rosy whites, spots, or odd filaments → discard.
- High-risk dishes (raw or lightly cooked): use only very fresh or pasteurized eggs.
4. Pro-Level Checks You Can Do at Home
4.1. Crack into a separate bowl
Look for a firm white, a rounded yolk that stands tall, and a clean smell. This is the most practical check.
4.2. Candling with a flashlight
Shine a strong light through the egg to judge the air cell size and spot defects. It’s surprisingly effective with a phone flashlight in a dark room.
5. Smart Storage: Temperature, Position, Hygiene
- 0–4 °C (32–39 °F), consistent cold; avoid the door shelves.
- Keep in the original carton to reduce odor absorption and protect shells.
- Pointy end down so the air cell stays at the top and the yolk remains centered.
- Do not wash eggs before storage—washing removes the protective cuticle.
- Wash hands/utensils after touching raw shells.
egg freshness egg float test how to store eggs
6. Common Myths (Busted)
- “If it sinks, it’s safe.” Not necessarily—sinking shows freshness, not sterility.
- “Always wash eggs before refrigerating.” No—washing strips the protective cuticle.
- “Floating eggs are always spoiled.” Floating means older; judge by smell and looks after cracking.
- “Yolk color shows freshness.” Yolk hue depends mostly on the hen’s diet.
7. Food Safety Essentials
- Crack into a separate bowl before adding to a recipe.
- Strict hygiene: wash hands, sanitize tools/boards.
- Cold chain: don’t keep eggs at room temp longer than necessary.
- Vulnerable groups: avoid undercooked egg unless pasteurized.
8. Which Eggs for Which Recipes?
| Application | Freshness | Why |
|---|---|---|
| Mayonnaise, raw dressings, tiramisu | Ultra-fresh / pasteurized | Better stability; safety first |
| Poached or soft-boiled | Very fresh | Thick whites keep a neat shape |
| Baking (cakes, cookies) | Moderately fresh | Aged eggs can whip well and are fully cooked |
| Hard-boiled | Older acceptable | Larger air cell → easier to peel |
9. Quick FAQ
Do old eggs always float?
Usually, yes—because the air cell grows. Still, judge by smell and appearance after cracking.
Is a sinking egg guaranteed safe?
No. The float test indicates age, not absence of bacteria. Inspect and cook properly.
How long do eggs last in the fridge?
With good cold storage (0–4 °C), several weeks beyond packing are common, but always verify smell/appearance.
Best eggs for poaching?
Very fresh—thicker whites hold a compact form in the water.
Explore more in English: Personal Chef Services in Romania · Hire a Private Chef — Cost & Benefits · Chopping Board Color Code (Kitchen Safety) · Cherry Tuille Recipe
10. Book a Private Chef Experience
I’m Chef Voicu Florin, a private chef available across Romania. I design clean, balanced menus with a focus on fresh, high-quality ingredients and modern techniques. Tell me about your occasion and I’ll craft a proposal that fits perfectly.
More English resources: Personal Chef Services · Hire a Private Chef — Cost & Benefits · Chopping Board Color Code · Cherry Tuille Recipe · Methocel in Molecular Gastronomy