Martin Earl and Tom Wiandt discuss the top 5 mistakes made when measuring food temperatures and ensuring food safety. They are: 1) failing to stir liquids and semi-liquids before measuring, which can lead to inaccurate non-uniform temperatures; 2) failing to measure the thermal center of foods, where the lowest temperature will be; 3) using infrared thermometers to measure internal food temperatures, as they only measure surface temperatures; 4) using inaccurate thermometers for critical temperature measurements without testing their accuracy; and 5) using paper logs that can contain errors compared to digital solutions. The presenters provide advice and demonstrations on properly measuring temperatures through stirring, finding the thermal center, using infrared thermometers, and choosing accurate devices.

1. Top 5 Food Safety
Thermometer Mistakes and
How to Avoid Them, Part 1
Proper Measuring Techniques and Exploring the Mysteries of Infrareds
Special Guests Martin Earl, Culinary Editor,
and Tom Wiandt, Chief Metrologist
Oct 21, 2021

2. Martin Earl, Culinary Editor
• graduated 2007 from University of Utah with a BS in physics
• MA in History and Philosophy of Science from Indiana University
Bloomington
• Associate’s Degree in Culinary Arts/Chef Training from Ivy Tech,
Bloomington
• executive chef at C3 in Bloomington
• has worked as a copy editor, cheese monger, culinary sales specialist,
dining hall manager, sous chef, and executive chef
• certified food handler, ServeSafe, trainer in food safety
• Culinary Editor at ThermoWorks since 2017 where he oversees both the
culinary operations in our demo kitchen/BBQ patio and the writing and
customer engagement on the ThermoBlog (blog.thermoworks.com)
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3. Top 5 Food Safety Mistakes – Part 1
1. Failing to stir liquids and semi-liquids before measuring
2. Failing to measure the thermal center of foods to find the lowest
food-safe temperature
3. Using an infrared thermometer to test internal food temperatures
4. Using an inaccurate thermometer for critical food safety
measurements and not properly testing its accuracy before use
5. Using paper logs that lead to erroneous data when digital solutions
are readily available
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4. Mistake #1 – Failing to Stir
Without Stirring:
• Temperature nonuniformity exists throughout and be more pronounced the higher the temperature
• Product will cool as it gets closer to colder environment (air temperature)
• Nonuniformity errors will prevent getting an accurate reading
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5. Liquid Measurement Nonuniformity Video
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6. Proper Measurement of Liquids Video
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7. Mistake #2 – Failure to Measure Thermal
Center
• Temperature at the center will be
lower than those at the edges
• Finding the true thermal center can
be tricky without proper technique
• You’ll need to understand the
measurement zone of your sensor
• Slight movement with a true instant
read will show the lowest temp
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8. Proper Internal Measurement Video
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9. Proper Semi-Solids Measurement Video
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10. Download Our
“How to
Accurately
Measure Hot &
Cold Holding
Pans” Poster
PDF
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11. Tom Wiandt
• graduated 1982 from US Air Force Precision Measurement
Equipment Lab
• has worked in DoD, nuclear power, instrument manufacturing,
laboratory accreditation, and independent consulting
• positions at Fluke, Hart Scientific, Southern California Edison,
Northrop, USAF before joining ThermoWorks
• trainer, consultant, and laboratory assessor for NVLAP, A2LA, and LAB
• member of ASTM since 1995—Chairman of ASTM E20 on
Temperature Measurement from 2012 to 2017
• awarded the Award of Merit and granted the title of ASTM Fellow
in2011, the highest award presented by ASTM
• Chief Metrologist at ThermoWorks since 2018
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12. Mistake #3 – Infrared Thermometers
Used to Test Internal Temperatures
Infrared thermometers measure temperature without contact based on
the collection of emitted infrared radiation from the target that is
electrically converted to a temperature reading. Infrared thermometers
typically use a lens to focus emitted energy onto a detector called a
thermopile, which is then converted to temperature.
• Measure surface temperature only, not internal
• Measure temperature from a distance
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13. How Infrared Thermometer Works
• Organic objects emit thermal energy
from its surface at different rates (emissivity)
• IR thermometers measure an object’s emitted
thermal energy and convert to temperature based
on emissivity value
“Emissivity is defined as the ratio of the energy radiated from a
material's surface to that radiated from a perfect emitter, known as
a blackbody, at the same temperature and wavelength and under
the same viewing conditions. It is a dimensionless number between
0 (for a perfect reflector) and 1 (for a perfect emitter).”
(NPL, United Kingdom)
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14. Emissivity Table
• https://www.thermoworks.com/emissivity-table
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15. Adjusting Emissivity Video
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16. • Understand the distance to spot ratio so you know exactly what
you’re measuring (more in a future webinar)
Infrared Thermometer Tips for Food
Measurements
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17. • Find the appropriate emissivity for the food you’re measuring – most
will be around 0.97
• IR thermometers are also great for griddles and spot temps of surfaces
• For liquids and semi-solids, stir or pry away to get to the thermal
center
Infrared Thermometer Tips for Food
Measurements (cont.)
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18. Properly Measuring Liquid with an IR Gun
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19. • Allow equilibration time with large changes in ambient like walk-ins
• For highly reflective surfaces, like aluminum pans, coat with a layer of
oil before measuring (oil has an emissivity of 0.97)
Infrared Thermometer Tips for Food
Measurements (cont.)
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20. Using Oil to Measure a Reflective Pan
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21. Helpful products
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20% Off Thermapen ONE 20% Off IRK-2 20% Off IRFS
The only true “instant-read.” Accurate
to ±0.5° F in 1 second or less.
Expanded range to 1022°F, circle
laser and Type K probe port
Pre-set to food emissivity 0.97
Use for all food safety applications

22. Next Session:
Thursday, November 4th, 10:00-10:30am MDT
• Top 5 Food Safety Thermometer Mistakes, Part 2
• Dealing with Measurement Inaccuracy and the Paper Log Trap
This Session:
• Replay of this session going out by email
• Go to www.thermoworks.com/webinar-series
• Share with colleagues and friends
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