Egg boiling calculator

What is an egg boiling calculator?

An egg boiling calculator is a free online tool designed to calculate the optimal cooking time for eggs based on their size, storage temperature, and the altitude above sea level where they are being boiled. It considers the egg’s properties, as well as the changes in boiling temperature of water at various altitudes.

Relationship between altitude and boiling temperature of water

At higher altitudes, atmospheric pressure is lower, which decreases the boiling temperature of water and can lead to longer cooking times for eggs. For example, at sea level, water boils at 100°C, but at 2000 meters elevation, the boiling temperature can be around 93°C. The calculator accounts for these changes to provide accurate cooking time calculations.

Types of eggs: soft-boiled and hard-boiled

Achieving perfection in soft-boiled and hard-boiled eggs requires different cooking times. Soft-boiled eggs have a runny yolk and slightly set white, while hard-boiled eggs should be fully firm. The calculator helps determine the optimal time based on user-inputted parameters.

Scientific aspect of boiling eggs

“The Science of Boiling an Egg” by Charles D. H. Williams provides an in-depth explanation of the factors leading to perfect egg boiling, such as egg materials, temperature, and boiling conditions. Read the full study for more detailed information.

How to properly boil eggs?

There are two main approaches: starting with cold water or placing eggs into boiling water.

• Cold Water: Place eggs in a pot of cold water and bring it to a boil. This method gradually heats the eggs, reducing the risk of cracking. It is suitable for both hard and soft-boiled eggs.

• Boiling Water: Add eggs directly to boiling water. This reduces the overall time eggs stay in the water, which might be preferable for soft-boiled eggs. Handle carefully to prevent cracking from thermal shock.

Both methods have their advantages, and the choice depends on texture preferences and desired doneness.

Timing the cooking

Cooking time typically starts once the water has reached a boil when beginning with cold water. For the boiling water method, time begins as soon as the eggs are submerged.

Formula

The formula to calculate the egg’s cooking time is as follows:

$t_{\text{cooked}} = \frac{M^{2/3} c \rho^{1/3} K \pi^2 (4\pi/3)^{2/3}}{\log_e[0.76 \times (T_{\text{egg}} - T_{\text{water}}) /(T_{\text{yolk}} - T_{\text{water}}) ]}$

Where:

• $M$ — mass of the egg (g)
• $\rho$ — density of the egg (g/cm³)
• $c$ — specific heat capacity of the egg (J/g·K)
• $K$ — thermal conductivity of the egg (W/cm·K)
• $T_{\text{egg}}$ — initial temperature of the egg (°C)
• $T_{\text{water}}$ — temperature of the water (°C)
• $T_{\text{yolk}}$ — desired yolk temperature (°C)

Examples

Example 1: Starting with cold water, a medium egg (58 g) refrigerated to 4°C cooks in about 4 minutes for soft-boiled and 6 minutes for hard-boiled from the point of boiling at sea level.

Example 2: Placing a small egg (50 g) into boiling water will require 3 minutes for soft-boiled and about 5 minutes for hard-boiled at sea level.

Notes

• The formula is based on findings from “The Science of Boiling an Egg” by Charles D. H. Williams.
• Parameters such as density, specific heat capacity, and thermal conductivity are average values for eggs.

FAQs

How to account for altitude when boiling eggs?

Altitude affects the boiling temperature of water. At higher altitudes, the boiling point is lower, which means cooking time should be increased. The calculator allows you to factor this into your calculations.

How long to boil a medium egg for soft-boiled?

A medium egg weighing 58 grams takes about 4 minutes to become soft-boiled at sea level. This may vary with altitude.

What is the significance of the egg’s initial temperature?

The starting temperature influences the cooking time. Eggs directly from the fridge require more time compared to room-temperature eggs.

Should I use cold water or boiling water?

The choice between starting with cold or boiling water depends on egg texture preferences. Both methods have pros and cons.

How to prevent eggs from cracking?

To reduce the risk of cracking, use room-temperature eggs and carefully lower them into water, boiling or not, and boil gently to minimize thermal shock.