Which kitchen thermometer should I buy?

Thermometers are the piece of kit that most reliably improves home cooking, because they replace guesswork on the questions that matter most — is the chicken done, is the oil at frying temperature, has the reheated food reached 75°C. The choice is mostly about speed and where the sensor is.

Step by step

1. Start with a digital instant-read probe.A folding or pen-style probe that reads in 2–5 seconds. Use it for meat, fish, bread, reheated food and oil. Look for a thin tip, which disturbs the food less and reads faster, a wide range covering at least -20°C to 250°C, and a waterproof or splashproof body. This is the one thermometer every kitchen should own.
2. Add a leave-in oven probe if you roast.A probe on a heatproof cable that stays in the joint with the display outside the oven, usually with an alarm you set to the target temperature. It removes the need to open the oven at all and it is the easiest way to stop overcooking a large piece of meat. Wireless versions do the same without a cable trailing out of the door.
3. Know what an infrared gun does and does not do.It reads surface temperature only, instantly and without contact. That makes it good for checking a pan, a griddle, a pizza stone or the surface of hot oil, and completely useless for telling you whether the middle of a chicken is cooked. Buy one as a second thermometer, never as a first.
4. Consider a fridge and freezer thermometer separately.A cheap dial or digital unit that lives in the fridge and tells you whether it is actually running at 0–5°C, and the freezer at around -18°C. It answers a different question from a cooking thermometer and it is worth the couple of pounds.
5. Judge a sugar or jam thermometer on range and clip.Sugar work runs up to 160°C and beyond, and needs the sensor at a consistent depth, so a clip that holds it against the pan without touching the base matters. A good digital probe with a clip does this as well as a traditional glass one and reads faster.
6. Check for calibration ability before buying.Any thermometer drifts. The useful ones can be corrected — a reset hole or button combination on a digital unit, a nut under the dial on an analogue one. A sealed unit that cannot be adjusted has to be replaced when it drifts.
7. Ignore the pop-up timer that came with the turkey.Those single-use plastic indicators trigger well above the temperature poultry needs, so a bird cooked until it pops is usually overdone and dry. Use a probe in the thickest part of the thigh, away from the bone.

Tips

• Speed matters more than the last half degree of accuracy. A probe that takes twenty seconds means the oven door is open for twenty seconds and you will stop using it.
• Measure in the thickest part, away from bone and away from any fat pocket, and take a second reading somewhere else. One reading in the wrong place is how undercooked chicken gets served.
• A thermometer is the answer to almost every 'how long do I cook this for' question, because time is a proxy for temperature and a bad one.
• Check any new thermometer against iced water before you trust it. New does not mean accurate.

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