Double the quantity does not mean double the cooking time – this is the most common mistake in the kitchen. Heat penetrates from the outside inward, and a joint twice as heavy has more mass but not proportionally more thickness. The key factor is the core temperature, not weight alone. Our calculator provides realistic estimates.
Step by Step: How to Use the Cooking Time Calculator
- Enter the original recipe details: For example 1.5 kg pork joint at 175°C, 90 minutes.
- Enter the new weight: For example 2.5 kg.
- Scaling factor: 2.5/1.5 = 1.67×. Do NOT multiply the cooking time by 1.67!
- Cooking time formula: New time ≈ original × √(new weight / original weight). Here: 90 × √1.67 = 90 × 1.29 = 116 minutes.
- Core temperature as the target: More reliable than times: use a meat thermometer. Pork: 72°C, beef medium: 60°C, chicken: 80°C.
Practical Examples
Chicken 1.2 kg → 1.8 kg: Original 60 min → estimated 60 × √1.5 = 73 min. Confirm with a thermometer at 80°C core temperature.
Biscuit baking time: Baking two trays at once: same baking time, but use the fan setting and swap trays halfway through. Baking time barely changes.
Smaller cake tin: Round 26cm tin → 20cm tin: the batter is deeper, so extend baking time by 10–15 minutes and lower the temperature by 10°C (the centre must be cooked through without the edges burning).
Core Temperatures as Cooking Targets
- Beef rare: 55–58°C
- Beef medium: 60–65°C
- Pork: 70–75°C
- Chicken/turkey: 80–85°C
- Fish: 55–60°C
- Bread: 96–98°C (internal)
Frequently Asked Questions (FAQ)
Why is a meat thermometer better than cooking times?
Ovens heat unevenly, meat quality varies and the shape and thickness of a joint can differ significantly. A thermometer measures the core temperature directly – the only reliable criterion for "done".
What does "resting time" after roasting mean?
Let the meat rest, loosely covered, for 5–15 minutes after removing it from the oven. Juices redistribute back into the tissue – the meat stays juicier when carved.
Why are baking times more predictable than roasting times?
Baking (cakes, bread) is more reproducible: dough composition and tin shape are constant and oven temperature is calibrated. With meat, water content, fat percentage and meat quality all vary.
