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Best Thermometer Consumer Reports

Back a few years ago, glass thermometers were quite popular for checking the temperature. Nowadays, the plastic or digital thermometer has mostly taken the glass thermometer’s place. But those cannot match the accuracy level of determining the temperature of glass thermometers. However, there are still some cases where glass thermometers are still used, such as nurseries, schools for science experiments, pharmaceuticals labs, and food & beverage industries. 

If you also need one, then I have got the five best glass thermometer reviews for you in this article. From here, you can pick the most suitable that fits your needs. Since glass thermometers have become rare nowadays, so my review can help you find one.

How Does a Glass Thermometer Work

Around the world, the glass thermometer is the most commonly used thermometer for measuring body temperatures. An enclosed glass tube connected to a reservoir has a small internal diameter (like a lumen). Fluid in reservoirs and tubes rises at higher temperatures as they expand.

There is a scale on the tube and fluid expansion indicates the temperature.

Top Picks : 5 Best Glass Thermometer

Last update on 2022-11-24 / Affiliate links / Images from Amazon Product Advertising API

Glass Thermometer Comparison Table

Geratherm Mercury Free Oral Glass Thermometer  Hospital tested FDA listedMercury-free  
Mercury-Free, Glass, Oral Thermometer C/F  FDA listedDual-scale readingLatex-free  
SP Bel-Art, Liquid-In-Glass Laboratory ThermometerTemperature range: 20-110 degrees Fahrenheit Made for lab use only contains organic liquid  
Farberware Glass Thermometer  For deep fry, oil temperature reading: 100-450 degrees FahrenheitIncludes an adjustable clip  
8 Inch Floating Glass Thermometer  Dual-scale readingWeighs 2.39 ounce rubber grip handle  

Top 5 Best Glass Thermometer Reviews

1. Geratherm Mercury Free Oral Glass Thermometer

The Geratherm glass thermometer is the best oral thermometer till now for its non-toxic, safe, and reading accuracy at all temperature measurements. If you are tired of looking for a glass thermometer, don’t look anywhere and buy it. I am sure that this mercury free glass thermometer is going to be your best thermometer purchase.

Moreover, this amazing thermometer is FDA listed, so you can use it for measuring food & beverage temperature of any sort. This dual-scale thermometer is hospital tested too for use in patients of all ages, including children and the elderly. On a sweet note, you get an offer of a limited lifetime warranty from Geratherm on this thermometer.

Key features:

  • Hospital tested
  • FDA listed
  • Mercury-free
  • It has a limited lifetime warranty
  • Dual-scale thermometer


Convenience: It is a dual-scale clinical thermometer with Celsius and Fahrenheit that offers ease of reading for everyone. For re-setting, you have to use the traditional shake-down glass. It comes with a sturdy and protective case for storing when not in use.

Safety: It is a safe, mercury-free oral thermometer with eutectic alloy instead of mercury. For your satisfaction, it is FDA and Hospital tested for the safety level. You can disinfect it easily for next use.

Temperature reading: This uniquely fluted glass thermometer can read temperature with 100% accuracy between 95.5 to 108-degree Fahrenheit. The scaling is effortless to read with marks of 10 degrees increment.


  • It is non-toxic and safe to use
  • Dual-scale reading makes it convenient to use
  • Provides accurate temperature reading
  • It comes with a protective case for storing
  • It is easy to sterilize and disinfect


  • The warranty period is low

2. Mercury-Free, Glass, Oral Thermometer C/F

Mercury-Free, Glass, Oral Thermometer C/F

Another gem in the list of glass oral thermometer categories from Geratherm for those whose budget is a bit low, yet they want to get their hands on the best glass thermometer once and for all. This clinical thermometer by Geratherm is almost the same as the previous one, but the liquid used is different in it. This one has Galinstan, again, a safe and non-toxic liquid used as a substitute for mercury.

This glass thermometer for fever, too, is FDA-approved for being safe for humans and the environment. It has dual-scale temperature reading that provides the highest accuracy temperature read every time. At such an affordable price, you won’t get a better deal for a mercury-free glass thermometer.

Key features:

  • FDA listed
  • Dual-scale reading
  • Latex-free
  • The liquid used is Galinstan
  • It takes 3 minutes for taking read


The liquid used: It is a safe, environment-friendly, and non-toxic oral thermometer with Galinstan, which is a special combination of gallium, indium, and tin instead of mercury. For your satisfaction, it is FDA tested for proving their safety level. You can disinfect it easily with alcohol dipped cotton for next use.

Convenience: It is a dual-scale clinical thermometer with both Celsius and Fahrenheit reading that offers ease of reading for everyone. Also, it comes with a protective sheath for safe and secure storage while not using. The oval shape design prevents the thermometer from rolling off a flat surface and makes it comfortable to hold.


  • Comes with sturdy and protective covering for storage
  • Provides accurate reading consistently
  • Easy to disinfect with alcohol-based sanitizer
  • Comfortable to hold and easy to read
  • Non-toxic and safe for the environment
  • Affordable price


  • Does not provide a warranty with this model

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3. SP Bel-Art, Liquid-In-Glass Laboratory Thermometer

SP Bel-Art, H-B DURAC Plus Pocket Liquid-In-Glass Laboratory Thermometer; 20 to 120F, Closed Plastic...

Those who are looking for a laboratory thermometer that offers safety, accuracy, and durability all at once, check out this one. This lab glass thermometer is filled with organic liquid for safer use for lab use, wastewater treatment, etc. However, they are strictly forbidden for human use.

Moreover, it comes with a closed plastic case for secure storage after use. And, this specific one has a temperature range between 20 to 110 degrees Fahrenheit. So, if you require more or less, then you can pick from the other options available.

Key features:

  • Temperature range: 20-110 degrees Fahrenheit
  • Made for lab use only
  • Contains organic liquid
  • Meets NIST specifications
  • Full immersion thermometer


Reliability: The liquid used in this glass thermometer is organic and environment-safe. Moreover, this thermometer by space technology is NIST approved for advanced temperature measurement, for maintaining standard and using technology. So, you can highly trust this thermometer for everyday lab work.

Convenience: It is a fully immersive thermometer with a length of 160 mm. Also, this length makes the thermometer easy to hold. It comes along with a durable plastic case for secure storage after use and white back glass. You can fully rely on the accuracy of the temperature reading on this lab glass thermometer by SP Scienceware.


  • A very reliable and accurate temperature reading
  • It comes in different temperature ranges
  • Has the closed plastic case for safe storage
  • Non-toxic and safe
  • Easy to use and hold


  • Scale reading does not include Celsius

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4. Farberware Glass Thermometer

Farberware Deep Fry Glass Thermometer, Clear

If you are a chef or professional cook of any sort who highly believes in the temperature measurement of food while cooking, then I have a deep fry glass thermometer for you by Farberware. Farberware has a specialty in creating glass thermometers for food temperature. Suppose this one is for deep fry; there come others for meat, refrigerator food, oven food, etc. 

This lightweight thermometer provides an accurate deep fry oil temperature reading between 100 to 450 degrees Fahrenheit. You can also read the temperature easily from its easy-to-read temperature zones. All over, it is the best investment for the purpose it serves.

Key features:

  • For deep fry oil temperature reading
  • Temperature reading: 100-450 degrees Fahrenheit
  • Includes an adjustable clip
  • Weighs 1.76 pounds
  • Style: Glass candy


Convenience: For convenient temperature reading, the thermometer has easy-to-read temperature zones within a range of 100 to 450 degrees Celsius. Also, there comes an adjustable clip which you can clip at the side of your pot to prevent the thermometer from hitting the pot. Furthermore, for easy understanding, there are simple instructions on the protective storage cap of the thermometer.

Safety: Although there is nowhere directly mentioned that this thermometer is mercury-free. But Farberware’s glass thermometers are always free from this toxic liquid, and old users know that. Another reliability of its safety is that when the temperature starts to increase, the liquid inside the thermometer turns blue. If there was mercury, it would have turned silver or ash in color.


  • Very easy to use and provides an accurate reading
  • Has easy-to-read reading zones
  • Very affordable
  • Includes and adjusting clip to keep the thermometer stable
  • The storage case contains information regarding temperature for easy understanding


  • The glass used is fragile

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5. 8 Inch Floating Glass Thermometer

8 Inch Floating Glass Thermometer

The last one in my best glass thermometer review is this 8 inches Floating Glass Thermometer by Monster Brew. If you are wondering what this thermometer is for, then it is for reading the temperature of beer or wine’s fermentation. This kind of thermometer is quite rare and hard to find, so if you were looking for such a glass thermometer, there it is for you.

It is a dual-scale reading thermometer with a scale ranging from 0 to 220 degrees Fahrenheit and -20 to 100 degrees Celsius. Moreover, it is made with professional-grade glass for all professional wine and beer brewers. Get this glass thermometer for getting the perfect tasting beer and wine every time without fail.

Key features:

  • Dual-scale reading
  • Weighs 2.39 ounces
  • Rubber grip handle
  • Temperature scale: 0 to 220 degrees Fahrenheit, -20 to 100 degrees Celsius


Convenience: It is a dual-scale glass thermometer with Celsius and Fahrenheit that offers ease of reading for everyone. The floating ability enables convenient temperature testing. Moreover, the rubber handle offers an easy and stable grip.

Temperature: The temperaturescale ranges from 0 to 220 degrees Fahrenheit and -20 to 100 degrees Celsius, which provides a faster and accurate reading.


  • Made from professional and premium-grade glass
  • It has an easy-to-grip rubber handle
  • Length is perfect for full immersion
  • Provides fast and accurate reading
  • Floats for comfortable testing
  • Very inexpensive


  • Do not come with a protective storage case

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Buying Guide for Best Glass Thermometer


If you don’t know where to start from or what to consider before purchasing a glass thermometer, then read out my brief guide on this. Even though it may seem like buying a thermometer is not a tough job, but there are still a few things you must know. If you take notes of these few things, then you are good to go with your thermometer.

Sturdy built

Glasses have more fragility, so make sure your glass thermometer is either made with high quality and sturdy borosilicate glass or has a protective backing to prevent them from breaking. The glass thermometers can break in two conditions: when it is encountered to extremely high or low temperature; secondly, when it falls, of course. So, a sturdily built glass thermometer will free you from that worry.


Traditional thermometers, such as glass ones, have a tested and certified liquid in them to determine temperature with accuracy. However, mercury is poisonous and unsafe if it comes in contact with any living being. As a substitute for mercury, many safe liquids are used in modern glass thermometers. So, stay away from the mercury oral thermometer for a safe and secure temperature reading.

Ease in reading

An easy reading and stable temperature will save your time and energy of re-reading the same thing again and again. Therefore, make sure that the thermometer provides stable reading and is easy to use.


Some region’s people understand Fahrenheit scaling whereas others understand Celsius. Therefore, before buying the thermometer, make sure you consider the scale reading of it, and it is your preferred one. Or else, you can take the hassle of converting the temperature every time.

There are some thermometers that come in dual-type scale reading at once. Also, keep in mind to check that the thermometer has the range of temperature reading you require.

How to Read a Glass Thermometer

Many people have never seen a glass thermometer and if you’re one of them, this post is for you. A glass thermometer displays the temperature by using mercury inside the tube to move up or down depending on how hot it is outside.


1. Check your thermometer to see what kind it is.

2. Verify that a glass thermometer has not been cracked or broken at the tip. If the thermometer is broken or cracked, do not use it.

3. Face the thermometer’s numbers so that the numbers are at eye level.

4. See if there are numbers and a measurement scale on the black lines. (Up and down) These vertical lines represent temperatures. The most common thermometer scales measure temperature in Fahrenheit and Celsius. Take a look at the °F (degrees of Fahrenheit) numbers.

  • There is a long line for each degree of temperature.
  • Every line is sandwiched by four shorter lines, each indicating 0.2°F (two tenths) of a degree of temperature.

5. Between the numbers and the vertical black lines, you will see a line of fluid.

6. Find the number that corresponds to the point where the column of fluid ends.

7. It is always advisable to start the thermometer’s reading below the first number on the line. The glass thermometer can be shaken down if necessary. You need to hold it firmly opposite the tip, then flick your wrist quickly. Be careful to keep objects and people away from you when shaking.


How do I know if my glass thermometer is working?

  • Glass thermometers usually take a minute to provide temperature readings. First, shake the thermometer well to reset it below 94-degree Fahrenheit. Then insert the stem into a glass of lukewarm water without touching the glass’s bottom and keep for a minute. Take it out, and see that if the temperature has increased for the water’s heat, you know that your glass temperature is working.

When can a glass thermometer be used?

  • A clinical glass thermometer is used for measuring human body temperature orally. There also comes laboratory glass thermometers for lab uses. However, the ones with mercury liquid in them must not be usable in food & beverage temperature measurement because if they break, all the mercury will go into the food, which is very dangerous.

How long do you take the temperature with a glass thermometer?

  • It takes as little as one minute to mostly three minutes or so for a glass thermometer temperature reading. If, in a minute, your glass thermometer fails to take the reading, then you might need a new thermometer because it has damaged for some reason.

Do glass thermometers work?

  • Yes, glass thermometers are the fastest and the most accurate temperature reader than other types of thermometers. They come in a variety of ranges for different types of temperature measurement.

Are thermometers made of glass?

  • Most of the classic thermometers are made out of glass for their due to their high thermal expansion and low coefficient. However, digital thermometers are mostly made from high-quality plastic cases too.

Final Verdict

You now have the freedom to pick the best glass thermometer for your purpose and enjoy fast reading with the most accuracy. These glass thermometers come from very reliable and trusted manufacturers who have sustained with their glass thermometers in the digital world of digital thermometers.

All the thermometers are more than safe and secure to use as they are completely mercury-free for modern-day requirements. Hence, what are you waiting for to pick your desired glass thermometer?