ZWILLING Sorrento Plus Double-Walled Glass 15oz Mug – Infrared Review
Tested at 66°F | IR Photography Included
The ZWILLING Sorrento Plus Double Walled Glass 15oz Mug shown side-by-side in infrared (left) and visible light (right)
Introduction
The ZWILLING Sorrento Plus Double-Walled Glass 15oz Mug is designed to keep your beverages at a stable temperature for longer while remaining comfortable to the touch. Its dual-layer borosilicate glass construction promises better insulation than standard single-walled mugs. To put these claims to the test, we used infrared (IR) imaging to capture how the mug’s surface temperature evolves over time after filling it with near-boiling water. Below are the full details of our test, along with a 26-interval breakdown of temperature readings and observations.
Test Setup
Thermal Imaging: We used infrared (IR) photos to measure surface temperature changes over time.
Elevation: 4,400 feet above sea level (At this elevation, the boiling point of water is 204°F rather than 212°F at sea level.)
Water Temperature: 204°F (Boiling)
Ambient Temperature: 66°F
Observation Duration: 40 minutes
Key Temperature Readings and IR Photos
Empty
- 66.3–66.0–66.0°F
- The mug’s baseline temperature matched the ambient environment before filling.
Pouring (Initial Contact)
- 66.4–66.6–70.0°F
- As the near-boiling water (204°F at 4,400 ft) enters, the mug’s interior and lower walls heat first, while the top remains cooler.
30 Seconds
- 750.7–72.5–705.0°F
- Rapid heat transfer to the mug’s outer surface; handle still noticeably cooler.
1 Minute
- 87.5–84.4–85°F
- The outer wall warms noticeably, but remains well below scalding temperatures.
1 Minute 30 Seconds
- 100.5–93.2–92.1°F
- A sharper jump; the mug’s exterior is heating up but still cooler than a typical single-walled ceramic might be at this stage.
2 Minutes
- 108.6–100.3–97.8°F
- Approaches 110°F in some spots; nearing the threshold of “too warm” for prolonged direct contact.
2 Minutes 30 Seconds
- 113.9–105.4–101.8°F
- Some areas exceed 111°F, which can be borderline uncomfortable if you touch the mug body directly.
3 Minutes
- 117.2–109.1–104.5°F
- The top rim is often the hottest zone, while the handle stays noticeably cooler.
3 Minutes 30 Seconds
- 118.8–111.7–106.5°F
- Exterior remains quite warm; still notably below the temperature of the liquid inside.
4 Minutes
- 120.1–113.6–108.2°F
- Edges near 120°F on the upper portion, indicating continued heat transfer outward.
4 Minutes 30 Seconds
- 120.6–114.8–109.4°F
- Temperatures stabilize in the low 120s°F range at the rim.
5 Minutes
- 120.8–115.5–109.7°F
- Hovers around 120°F at the top; the handle remains a safer grip point.
5 Minutes 30 Seconds (Max Recorded Temperature)
- 121.1–116.1–110.3°F
- Peak exterior warmth, with the upper rim consistently the hottest region.
6 Minutes
- 121.0–116.1–110.2°F
- Maintains heat around the 120°F mark at the top, mid-110s°F on the sides.
6 Minutes 30 Seconds
- 120.7–116.1–110.3°F
- Minimal change; the mug continues holding its higher temperatures.
7 Minutes
- 120.3–116.1–110.2°F
- Slight dip at the top, but still over 120°F in spots.
7 Minutes 30 Seconds
- 120.0–116.1–110.1°F
- Holds steady in the same range, indicating strong insulation.
8 Minutes
- 119.7–115.9–109.9°F
- Begins a gradual cooling trend, dropping 1–2°F at the top.
8 Minutes 30 Seconds
- 119.0–115.5–109.8°F
- Continues its slow decline; the mug remains notably warm.
9 Minutes
- 118.2–114.9–109.1°F
- Approaching sub-120°F territory overall, though still toasty to the touch.
9 Minutes 30 Seconds
- 117.5–114.5–108.5°F
- A consistent cooling pattern emerges across the surface.
10 Minutes
- 116.6–113.5–107.8°F
- The outer wall is more comfortable to handle; the liquid inside remains quite warm.
15 Minutes
- 110.3–108.3–103.2°F
- A noticeable drop from 10 minutes; warm but not uncomfortably hot.
20 Minutes
- 106.4–104.5–99.9°F
- Edges closer to moderate warmth on the exterior.
30 Minutes
- 99.4–98.8–95.1°F
- Near or just below 100°F, indicating the drink is no longer hot but still above room temperature.
40 Minutes
- 93.7–93.7–90.8°F
- By the end of the test, the mug’s exterior is mildly warm.
Analysis & Observations
Slower Heat Transfer
The double-walled construction clearly moderates heat transfer, as evidenced by relatively gradual increases in surface temperature during the first few minutes. While it does surpass 111°F (often cited as a threshold for discomfort), it takes longer to get there compared to a single-walled mug.
In previous tests, the I Love You Mug (Control) quickly soared to a max exterior temperature of 171.0–171.9–167.6°F at 1 minute 30 seconds, whereas the double-walled glass mug didn’t hit its peak of 121.1–116.1–110.3°F until 5 minutes 30 seconds. This striking contrast shows how the double-walled design significantly slows heat transfer to the outer surface, giving you a longer window of comfortable handling compared to a single-walled ceramic mug.
Handle Comfort
Throughout the test, the handle remains notably cooler than the mug’s upper rim. This allows you to pick it up without burning your fingers, even when the exterior wall creeps past 120°F.
Extended Warmth
The interior liquid likely stays hotter for longer because the mug’s outer surface never skyrockets to the extreme temperatures seen in single-walled ceramics. Around 10–15 minutes in, the beverage is still comfortably hot, whereas a standard mug would typically lose heat more quickly.
Cooling Phase
After about 8–10 minutes, the surface temperature levels off in the mid-110s°F range before steadily declining. By 30–40 minutes, it’s still above room temperature but no longer “hot.”
Pros & Cons
Pros
- Effective Insulation: Retains heat longer than typical single-walled mugs.
- Comfortable Grip: Even at peak temperatures, the handle stays relatively cool.
- Sleek Appearance: The transparent glass showcases your beverage.
- No Condensation: Ideal for cold drinks—no external sweating.
Cons
- Higher Price Point: Double-walled borosilicate glass often costs more than basic ceramic.
- Delicate Construction: Although durable for glass, it’s more fragile than stainless steel or thick ceramic.
- Peak Exterior Temps: The outer wall can exceed 111°F around the 2–7 minute mark, which some may find borderline uncomfortable to hold if they touch the mug body directly.
Final Thoughts
The ZWILLING Sorrento Plus Double-Walled Glass 15oz Mug delivers on its promise of better insulation, keeping liquids hotter for longer while ensuring you won’t scald your fingers—especially if you use the handle. Our IR data shows that the exterior does heat up into the low 120s°F but takes a few minutes to get there, giving you a comfortable window to handle it safely. By the 30–40 minute mark, the mug still holds warmth, though it’s no longer piping hot. If you value both style and function, and you’re willing to be a bit more careful with glass, this mug is a solid investment for daily coffee or tea rituals.
Have Questions?
Drop them in the comments below! And if you’ve used the ZWILLING Sorrento Plus Mug in real-world conditions, share your experience. We’d love to see how it performs for others!
Disclaimer: This review is not sponsored by ZWILLING. All observations and opinions are our own, based on personal testing and infrared photography.