Do packet cooking instructions lead to overdone food? We carried out a test to find out. We cooked four whole chickens to the time suggested on their packaging whilst monitoring the internal temperature. Our prediction was that each chicken would be cooked to a safe temperature long before the timer went off, resulting in dry meat.
The Chicken Experiment
We went to four different supermarkets and purchased a medium-sized chicken from each one. The supermarkets were Tesco, Waitrose, Aldi and Sainsbury’s.
We cooked each chicken using the same process:
- Removed from the fridge 20 minutes ahead
- Using the same oven and roasting tray
- Middle shelf of the oven
- 190 °C oven temperature
- Flavoured with olive oil and seasoning
- Covered with foil until the last 20 minutes of the cook
Each chicken then went into the oven for the time specified on its packet.
Temperature Monitoring
Before placing each chicken into the oven we inserted the temperature probe from our Digital Oven Thermometer.
This thermometer has a leave-in probe which means that you can continuously monitor the temperature of your cook, as well as setting a high temperature alarm.
Simply insert the probe into your meat, place the meat into the oven, and monitor the core temperature on the DOT screen. Use the arrows to set your meat temperature and hear an audible alarm once it's cooked.
The cooked temperature for chicken is 74 °C, so we programmed this into the DOT to find out how soon our chickens reached temperature.
The Results
Aldi
- Weight: 1.65kg
- Suggested cooking time: 1 hr 45 mins
- Time to reach 74 °C: 1 hr 13 mins
- Final temperature: 94 °C (20 °C overcooked)
Sainsbury’s
- Weight: 1.6kg
- Suggested cooking time: 1 hr 25 mins
- Time to reach 74 °C: 59 mins
- Final temperature: 98 °C (24 °C overcooked)
Tesco
- Weight: 1.36kg
- Suggested cooking time: 1 hr 25 mins
- Time to reach 74 °C: 57 mins
- Final temperature: 90 °C (16 °C overcooked)
Waitrose
- Weight: 1.5kg
- Suggested cooking time: 1 hr 45 mins
- Time to reach 74 °C: 1 hr
- Final temperature: 98 °C (24 °C overcooked)
Summary
The four chickens cooked for an average of 33 minutes longer than necessary and reached an internal temperature 21 °C higher than required.
Cooking times can vary between ovens and may be affected by factors such as other dishes being cooked at the same time. This likely explains why supermarkets tend to overestimate cooking times, as ensuring food safety is their top priority.
That said, the results of our experiment are clear: if you want shorter cooking times, juicier chicken and complete confidence in food safety, measuring the internal temperature of your meat is the only reliable way to know when it's done.
