BTaT Double Walled Glass 16oz Mug – Infrared Review
Tested at 66°F | IR Photography Included
BTaT Double Walled Glass 16oz Mug shown side-by-side in infrared (left) and visible light (right)
Introduction
The BTaT Double-Walled Glass 16oz Mug promises to keep your beverages hotter (or colder) for longer, similar to other double-walled designs. To see how it performs, we used infrared (IR) photography to capture surface temperatures at specific intervals—then compared these results to our previous tests with a standard ceramic mug (the control) and the ZWILLING Sorrento Plus Mug.
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
- 66.6–66.4–66.2°F
- The mug’s baseline temperature matched the ambient environment before filling.
Pouring (Initial Contact)
- 67.7–68.9–71.4°F
- As near-boiling water enters, the lower interior heats first, while the top remains close to ambient.
30 Seconds
- 71.8–71.9–74.6°F
- Initial heat transfer to the outer wall is moderate; handle area is still relatively cool.
1 Minute
- 86.5–82.9–85.2°F
- The exterior warms, but remains well below scalding.
1 Minute 30 Seconds
- 96.5–91.1–92.1°F
- A sharper rise; still cooler than a single-walled ceramic mug would be at this stage.
2 Minutes
- 104.3–97.4–97.6°F
- Approaching 105°F in some spots; comfortable to hold but noticeably warming.
2 Minutes 30 Seconds
- 109.5–102.1–101.3°F
- Edges above 110°F in areas, nearing a borderline “too warm” threshold for extended contact.
3 Minutes
- 113.0–105.8–104.3°F
- Top rim is typically the hottest zone; handle remains safer to grip.
3 Minutes 30 Seconds
- 115.4–108.4–106.2°F
- Exterior is quite warm; still below the temperature of the liquid inside.
4 Minutes
- 116.7–110.3–107.3°F
- Nearing 117°F on the rim, showing continued outward heat transfer.
4 Minutes 30 Seconds
- 117.4–111.3–107.8°F
- Temperatures hover in the high teens (°F) at the top, mid-110s°F around the center.
5 Minutes
- 117.9–112.1–108.4°F
- Approaching near-peak levels on the exterior; still manageable if held by the handle.
5 Minutes 30 Seconds (Max Recorded Temperature)
- 118.1–112.8–108.9°F
- Hits a peak around 118°F at the rim, consistent with other double-walled glass mugs.
6 Minutes
- 117.8–112.9–108.8°F
- Maintains a steady high temperature; minimal change from 5 minutes 30 seconds.
6 Minutes 30 Seconds
- 117.4–112.7–108.5°F
- Slight dip at the rim; the mug remains comfortably warm for sipping.
7 Minutes
- 117.3–112.7–108.5°F
- Almost identical to 6m30s; strong insulation keeps temperatures high.
7 Minutes 30 Seconds
- 116.8–112.4–108.3°F
- A gradual cooling trend begins; still over 116°F at the rim.
8 Minutes
- 116.3–112.2–108.1°F
- Continues cooling by about 0.5–1°F at the rim.
8 Minutes 30 Seconds
- 115.9–111.8–107.6°F
- Remains notably warm, though trending downward.
9 Minutes
- 115.3–111.3–107.0°F
- Dips below 116°F at the top; comfortable to handle on the body for brief contact.
9 Minutes 30 Seconds
- 114.7–110.7–106.4°F
- Cooling pattern is consistent; no sudden drops.
10 Minutes
- 114.1–110.2–105.8°F
- More comfortable to the touch; the beverage remains hot inside.
15 Minutes
- 108.8–105.3–101.3°F
- Notable drop from 10 minutes, but still above 100°F at the bottom.
20 Minutes
- 104.3–101.3–97.6°F
- Edges closer to moderate warmth on the exterior.
30 Minutes
- 97.6–95.2–91.8°F
- Falls below 100°F, indicating the drink is warm but no longer hot.
40 Minutes
- 92.6–90.8–88.1°F
- Mildly warm on the exterior; the contents are now lukewarm at best.
Analysis & Observations
Compared to the “I Love You” ceramic mug, which rapidly reached a scalding exterior (170°F+) within the first 2 minutes, the BTaT Double-Walled 16oz mug takes about 5–6 minutes to hit its peak (~118°F). This slower heat transfer is similar to what we observed with the ZWILLING Sorrento Plus mug, although the BTaT mug can hold a slightly larger volume (16oz vs. 15oz).
Slower Exterior Heating: The double-walled design delays the outer surface from hitting uncomfortably high temps, giving you more time to handle it without burning your fingers.
Sustained Warmth: The mug remains above 110°F at the rim for several minutes, helping keep your beverage hot longer than a single-walled mug would.
Gradual Cooling: By 30–40 minutes, the mug’s exterior approaches a comfortable 90–95°F range, indicating the beverage inside is heading toward lukewarm territory.
Pros & Cons
Pros
- Excellent Insulation: Maintains a hot interior while moderating the exterior temperature.
- Comfortable to Hold: Even at its peak (~118°F), it’s far below the 170°F+ spikes seen in standard ceramic mugs.
- Ample Capacity (16oz): Perfect for larger servings of coffee, tea, or other hot beverages.
- Aesthetic Appeal: Clear glass design highlights your drink.
Cons
- Potential Fragility: Double-walled borosilicate glass is durable, but still more prone to breakage than steel or thick ceramic.
- Peak Temps Still Hot: The rim can exceed 110°F, which might feel warm to the touch if you grip it above the handle.
- Price Premium: Quality double-walled mugs typically cost more than basic ceramic options, though this option is significantly cheaper than the ZWILLING Sorrento Plus
Final Thoughts
The BTaT Double-Walled Glass 16oz Mug delivers a similar performance to the ZWILLING Sorrento Plus in terms of insulation and comfort, with the added benefit of slightly larger capacity. In contrast to our control test with the “I Love You” ceramic mug, which heats up rapidly and loses heat faster, the BTaT mug steadily warms to a manageable ~118°F on the exterior while preserving the beverage’s heat for a longer period. If you enjoy leisurely sipping your coffee or tea and appreciate a visually appealing mug, the BTaT Double-Walled option is an excellent choice—just remember to handle it with care to avoid accidental breakage.
Have Questions?
Drop them in the comments below! And if you’ve used the BTaT Double Walled Glass 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 Brew To A Tea. All observations and opinions are our own, based on personal testing and infrared photography.