Different stages of cooking sugar require precise temperatures, as does the tempering of chocolate, and a sugar thermometer will take away any guesswork to ensure the correct results. Some models also register below-zero temperatures, making them very handy for churning ice cream. While the name doesn’t suggest it, they’re also useful when deep-frying, making preserves such as jam and marmalade, or whipping up homemade custard or yogurt.
If you’re planning to use a use a sugar thermometer for making jam, consider the rest of the equipment you will need – our handy guide to jam-making essentials includes the best jam pan and jars. If you make ice cream regularly, our best ice cream makers article reveals which are worth the investment.
If you’re looking for a thermometer for savoury cooking – such as barbecues and roasts – our best digital meat thermometers have extra functions such as doubling as carving forks, or include app functionality.
How to choose the best sugar thermometer
What different types of sugar thermometer are there?
Traditional metal or glass, liquid thermometer: a traditional liquid thermometer is made of metal or glass with no moving parts and needs no energy source; it relies solely on mercury or alcohol rising in the glass tube as it heats. The thermometer should be graded with the stages of sugar melting (hard ball, hard crack and caramel) and will often also show a jam setting point, a deep-frying temperature, and both Celsius and Fahrenheit are helpful. Ensure the sugar thermometer has some kind of hook to clip it onto the side of the pan.
Analogue probe thermometer: this can double-up as a meat thermometer, but ensure that it can also reach the high temperatures required for sugar (up to 200C). The simple dial is easy to read, and there is little to damage on them, unlike those made from glass. They should have a clip to attach them to a pan and have both Celsius and Fahrenheit measures. Probe thermometers can also come in handy in place of a skewer for testing when a cake is cooked – the probe should come out clean.
Digital thermometers: these are the real workhorses of the thermometer world, being multi-functional. They can be used for all liquids, meats and fish, for barbecues and testing cooked food for safety. Some will also double as oven thermometers. Most digital thermometers are battery operated and faster at displaying temperature, so there is no need to clip them onto the pan. A hold function switch is helpful to read the temperature easily when removed from the food, and it’s worth looking for a convenient button to switch between Celsius and Fahrenheit.
How to use a sugar thermometer
- Don’t let any thermometer touch the bottom of the pan as it will skew the reading, and those made from glass will shatter.
- Never put any kind of glass thermometer into scalding liquids; put them in while cold and raise the temperature gradually, or you risk the glass breaking.
- Wash your thermometer by hand (few are dishwasher-proof) and always dry thoroughly. Metal probes can be wiped clean with antibacterial wipes.
- Store thermometers separately from your usual kitchen equipment as they can damage easily.
- Check the accuracy of your thermometer from time to time. The quickest and easiest way is to put a pan of water on the stove, insert the thermometer, or hang it from the side of the pan, making sure it is not touching the bottom. Bring to a rapid boil and check the temperature, which should be be 100C (212F).
Best sugar thermometers at a glance
- Best overall thermometer: Thermapen professional £64.99
- Best budget digital thermometer: Judge digital thermometer £19.50
- Best versatile thermometer: Salter leave-in digital thermometer £24.99
- Best thermometer for smart design: Lakeland Thermospatula £14.99
- Best analogue thermometer: Kilner £17.50
- Best budget thermometer: Procook £5
- Best traditional sugar thermometer: ChefAid £5.75
- Best sugar thermometer for jams and marmalade: Taylor Pro £12.02
- Best thermometer for occasional use: Tala jam and confectionery thermometer £6.26
Best sugar thermometers to buy in 2021
Thermapen professional thermometer
Best all-round thermometer
The Thermapen professional is by far the most expensive thermometer we tested and a thermometer very much used by professional chefs. But it can also sit happily in the home kitchen.
It is small and cleverly designed to hold in the hand comfortably and comes in a range of colour options. Every seam around the casing is covered in soft silicone to seal the thermometer and prevent food lodging in the crevices. The casing is also washable and has antimicrobial technology to ensure cleanliness.
The steel probe is 11cm, which may not seem very long but is still enough to keep hands away from hot food. The probe folds neatly into the handle for storage and the sharp, pointed tip is securely protected by the silicone.
The Thermapen measures from -49.9 to 299.9C and has unparalleled accuracy thanks to thermocouple technology in the probe’s tip. In our test, it was immensely fast at displaying the temperature with 100% precision.
We loved the speed and precision, but our favourite aspect of this thermometer is the large 360-degree rotational display, which is light-sensitive, so it backlights when needed. It goes to sleep when left and springs to life when picked up. There are no buttons, or switches making it even cleaner.
Yes, it is expensive, but is multifunctional across meat and liquids and could quickly be something you find yourself reaching for regularly. If you often make sweets or cook a roast, we feel it is worth it.
Judge digital thermometer
Best budget digital thermometer
The Judge digital thermometer is made from light plastic but feels quite sturdy. It has been carefully designed with easy to read, clear large numbers and measures in both Fahrenheit and Celsius. There’s a helpful lanyard and a snap-on cover to protect the stainless steel probe when not in use and a strong clip on the back, so great for hooking onto an apron or jacket pocket.
The probe is sturdy and though not very long at only 8cm, will work as both a jam, candy and meat thermometer, which makes it incredibly versatile. Its narrow design means it won’t take up much space in a drawer.
In the test, it was easy to hold, but our hands had to get quite close to the hot fudge with the short probe. It reads quickly, so we didn’t have to linger too long and for accuracy, it was close enough to be insignificant.
The Judge is a good value-for-money, digital thermometer.
- Available from: Horwood £19.50
Salter leave-in digital thermometer
Best versatile thermometer
The Salter is a very well made, robust piece of kit with a strong steel cord and three strong magnets that stick firmly to the refrigerator, oven door or barbecue. The interface is a good size, straightforward, and easy to read, and there is an excellent instruction book outlining all its uses.
The thermometer comes with a handy stainless steel pan clip (particularly useful for jam and sugar work) but no instructions on how to fit it on. It took us some time to figure it out.
The probe is 17cm long and with a temperature range from -20°C to 250°C, it would work across sugar work, deep-frying and jam-making. It also doubles as an in-oven meat thermometer making it very useful for roasting, grilling and barbecuing, too.
The display gives you a range of pre-set temperatures for meats and sugar settings, as well as working with custom temperatures. In the test, it read the heat quickly and was impressively bang-on.
Best thermometer for smart design
The Lakeland Thermospatula is a very clever and smart device, neatly combining two pieces of kitchen equipment into one; a thermometer and a spatula. It is invaluable when making jam, fudge or tempering chocolate because as you stir, the built-in probe takes the temperature and displays this at the top of the handle. The screen is tiny and a little hard to read, although the numbers themselves are bold. The thermometer measures in both Celsius and Fahrenheit and it is easy to switch between the two.
When you need a probe for meat or cooked food, a gentle tug of the handle and the extensive 23cm long, sturdy probe slides out of the spatula for separate use. The probe has a temperature range of -20 to 240 C and the spatula is heat-resistant up to 220C. The probe may be long, but its reading speed is fast, and accuracy was spot-on. We also appreciated that with the probe removed, the spatula is dishwasher-safe.
The only (tiny) problem we had with Thermaspatula is that there is no way of attaching, sticking or hanging the spoon from the pan, so it can get a little bit messy – and we wish it came in prettier colours.
- Available from: Lakeland, £14.99
Kilner thermometer and lid lifter
Best analogue thermometer
- Available from: Kilner, £17.50
The Kilner thermometer is a simple analogue, dial probe, is robustly built, uncomplicated and has a charmingly vintage look. There’s a neat pan clip – making it easy to monitor temperatures – and both the dial and the clip are protected with silicone mouldings around the edges, so they’re easier to hold, protecting against accidental burns.
The dial has the largest display of the ones we tested, is easy to read and has temperature ranges from 0-240C, making it ideal for most preserving recipes. The read of the temperature was steady and had perfect accuracy in all our tests.
As an added extra, this thermometer comes with a separate lid lifter with a magnetic end, allowing you to safely lift sterilise lids out of boiling water to pop onto your Kilner jar when preserving.
We loved using this thermometer; it is simple and unfussy with spot-on accuracy.
ProCook deep-fry analogue thermometer
Best budget thermometer
This analogue stainless-steel Thermometer from ProCook is our best budget buy and is suitable for both sugar work and deep-frying with its 23cm probe. It is unfussy, with no fancy tricks, but it serves its purpose well.
The simple analogue dial has both Celsius and Fahrenheit measures and reaches zero to a staggering 300 C, so it will easily cover all bases.
We liked that there is a small movable blue arrow attached to the rim of the dial that can be positioned to the required temperature, making it so much easier to see when it hits the mark.
The ProCook was not the most robust thermometer, but it is sturdy enough to give years of service if handled with care. Given its price and the accuracy, it truly is a bargain.
- Available from: ProCook, £5
Chef Aid 10E01669 confectionary thermometer
Best traditional sugar thermometer
The Chef Aid glass thermometer is as old fashioned as they come with its pen-like frame and easy-to-read scale. It is not a fast thermometer (we realised that as we stood watching the slowly rising mercury), but it is accurate. The thermometer clips tightly to the side of the pan, though it does wobble about a little. We particularly liked the unique big red ball on the clip, which acts as a handle and makes removing the thermometer from the pan easy and safe.
As our fudge started to heat up, the gentle steam given off caused condensation on the glass, and it was hard to check the temperature, but this eased as the glass warmed up.
The thermometer will break easily, so it does need attention and careful handling, and without any form of a storage case, throwing this in the drawer could be disastrous. But, despite its apparent fragility, we liked this thermometer for its simplicity, its familiar traditional look and bargain price.
Taylor Pro stainless steel jam thermometer
Best sugar thermometer for jams and marmalade
The Taylor Pro jam and sugar thermometer is a hefty, robust stainless steel thermometer with a super-sized, extremely comfortable, heatproof handle.
It has the standard measurements from around 60 Celsius up to 200 Fahrenheit, and we particularly liked the size of the gauge, which is straightforward and easy to read. As is usual with this thermometer style, it is not fast to read, but the accuracy was perfect.
On the back, there is a silicone-covered stainless steel sliding clip for hanging the thermometer from the side of the pan, and it grips exceptionally well, helped in part by the silicone.
The Taylor Pro is a classic style jam and sugar thermometer and incredibly robust, so if taken care of, it should last for years. The only fragile part is the glass column for the mercury, but that is well fixed into the body of the thermometer.
Tala Jam and confectionary thermometer
Best thermometer for occasional use
- Available from: Amazon, £6.26
The Tala jam and confectionary thermometer is a simple straightforward thermometer made of good quality stainless steel with a reasonably-sized heatproof handle.
Its gauge goes from 40 to 200C with helpful markings for sterilisation, jam, different settings for sugar and deep-frying. The glass mercury tube is relatively small but held firmly in place, making it difficult to break. It is a slow read, which is usual for this type of thermometer, but we were impressed by its accuracy.
The thermometer comes with a sliding stainless steel clip at the back for attaching to the pan, but unfortunately, it was too big, so not very secure and twice the thermometer fell from the clip. With a bit of adjustment to tighten it up, it worked fine.
For the bargain price, the quality of this thermometer is a good.
How we tested sugar thermometers
We looked at the amount of information on the thermometer, its versatility and different functions, how easy it was to use and hold, or clip onto the pan, plus the ease of cleaning, storage and value for money.
We tested each thermometer using the BBC Good Food classic fudge recipe, which requires three critical temperature readings.
We also ran a side-by-side test of all thermometers for speed of reading and accuracy, immersing them in cold water and bringing them up to 100C (boiling point).
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This review was last updated in May 2021. If you have any questions, suggestions for future reviews or spot anything that has changed in price or availability please get in touch at goodfoodwebsite@