J. Kenji López-Alt - Here’s how to tell the age of an egg.
The video explains two methods to determine the age of eggs. The first method involves checking the egg carton for a Julian calendar date, which indicates the packing date. For example, a Julian date of 338 means the eggs were packed on December 2nd or 3rd. The second method is a water test: fresh eggs sink in water, while older eggs float due to increased air inside the shell. This is because eggshells are porous, allowing air to enter over time. The video also discusses the impact of egg age on cooking. Older eggs have looser whites and are better for scrambling or baking, while fresher eggs are ideal for frying, poaching, or boiling. Eggs can remain good for up to 60 to 120 days, often longer than expected.
Key Points:
- Check the Julian calendar date on the egg carton to find the packing date.
- Perform a water test: fresh eggs sink, older eggs float.
- Older eggs have looser whites, suitable for scrambling or baking.
- Fresher eggs are better for frying, poaching, or boiling.
- Eggs can remain good for 60 to 120 days, often longer.
Details:
1. 🔍 Introduction to Egg Freshness
1.1. Importance of Egg Freshness
1.2. Techniques to Determine Egg Freshness
2. 📅 Checking Egg Age with Packaging Information
- Egg freshness can be determined by examining the packaging on the egg carton.
- Look for the 'sell by' date, typically printed at the end of the box, to gauge the timeframe for best use.
- Identify the Julian date on the carton, a three-digit code representing the packing date, where January 1 is 001 and December 31 is 365, to determine the exact packing day.
3. 💧 Float Test for Freshness
- Eggs packed on December 2nd or 3rd are about 30 days old by January 5th, indicating they are relatively young.
- A fresh egg will sink when placed in water, indicating it is still good to eat.
- Older eggs float due to the expansion of the air cell inside them, which occurs as moisture and carbon dioxide escape through the shell over time.
4. 🌬️ Why Eggs Float
- Eggs tend to float in water as they age due to the porous nature of eggshells, which allows air to enter and moisture to escape over time.
- As eggs age, the air pocket inside the shell enlarges, causing older eggs to float while fresh eggs remain submerged.
- This phenomenon is a practical method for estimating the freshness of eggs, where a 30-day old egg will have a small air pocket, whereas much older eggs will have significantly larger airspaces.
- Understanding the science behind the buoyancy of eggs involves the role of eggshell porosity and its impact on the internal airspace, which directly affects whether an egg sinks or floats.
5. 🍳 Cooking with Eggs of Different Ages
- Older eggs have looser whites and do not stand as tall when cooked, affecting texture and appearance in dishes.
- A 30-day old egg holds its shape well, with a slightly looser white, standing taller than eggs much older.
- When poaching, younger eggs perform better due to firmer whites, creating a more compact and visually appealing result.
- Older eggs are preferable for making hard-boiled eggs as they peel easier due to the air pocket expansion over time.
6. 🥚 Cooking Recommendations for Different Egg Ages
- Older eggs are recommended for scrambling or baking due to their looser whites.
- Fresh eggs are ideal for frying, poaching, or boiling, ensuring tightly shaped outcomes.
- Boiling old eggs may result in dimples and off-centered yolks but remains practical.
7. ⏳ Longevity of Eggs
- Eggs remain fresh for much longer than expected, with 30-day old eggs still being relatively fresh.
- The sell-by date for eggs is typically set up to 60 days from when the egg was laid.
- Eggs can remain good for up to 90 days, or even over 100 to 120 days under certain conditions.
- It is challenging to spoil eggs unless there is a significant effort to do so.