Plaintiff Darin Edwin Pape brought this products liability action against Defendant Bodum USA, Inc. (“Bodum”), alleging that defects in Bodum’s coffee press caused him injury when the press’s glass shattered and hot water spilled onto his body.
Plaintiff’s expert Mingxi Zheng opined that a combination of (i) a manufacturing defect that allowed air bubbles to form within the French Press’s glass carafe, (ii) a design defect that allowed for direct contact between a protruding steel wire in the plunger and the French Press’s glass carafe, and (iii) thermal and mechanical stress from normal use of the French Press led the product to “ultimately fail.” Bodum filed a motion to exclude Zheng’s expert testimony.
Mechanical Engineering Expert Witness
Mingxi Zheng is a licensed professional mechanical engineer in California with a specialty in “metallurgy, fracture mechanics, and failure analysis.”
She received degrees in materials science and engineering and has worked as a materials scientist and mechanical engineer at various reputable institutions.
Discussion by the Court
Bodum primarily contended that Zheng’s conclusions are speculative because she has not tested her hypotheses or provided adequate support from the record.
a. Zheng’s Expert Testimony Is Reliable
First, Bodum claimed that Zheng provided no support for her conclusion that thermal stress contributed to the fracture. While Bodum may disagree with the strength or even the accuracy of Zheng’s conclusion about thermal stress, the Court determined that her opinion is based on factual evidence observed in the subject carafe as well as her own scientific expertise and research. Zheng’s opinion about thermal stress as a contributing factor is supported by actual observations that she has made of the French Press combined with research on common signs of thermal stress in glass.
Second, Bodum contested Zheng’s air bubble theory, once again arguing that it was not rooted in adequate testing or fact. The Court is sympathetic to Bodum’s criticisms of the gaps in Zheng’s air bubble theory, but it ultimately found that her opinion is not so “speculative or conjectural or based on assumptions that are so unrealistic and contradictory as to suggest bad faith or to be in essence an apples and oranges comparison.”
Third, Bodum took issue with Zheng’s expert opinion about the plunger, namely that the mechanical stress from the plunger as well as the protruding metal coil in the plunger contributed to the fracture.
Although the Court found Zheng’s plunger conclusions to be especially weak, it once again is constrained to conclude that they meet the relatively low bar for admissibility.
Although the Court found Zheng’s plunger conclusions especially weak, it was once again required to conclude that they met the relatively low bar for admissibility.
Finally, the Court declined to exclude Zheng’s expert testimony because of her apparent “failure to rule out obvious alternative causes of the fracture.” An expert need not rule out every alternative cause in forming an opinion.
c. Zheng’s Expert Testimony Will Assist the Jury
Given the complexities of glass fractography, Zheng’s expert testimony about the effects of thermal stress, air bubbles, and mechanical stress can help explain “how and why the French Press was defective” and caused Pape’s injury.
As to the matters of defect and causation, this Court is satisfied that her opinions “will assist the trier of fact” in making a decision in this case.
Held
The Court denied Bodum’s motion to exclude the testimony of Mingxi Zheng.
Key Takeaway
The Court excused Zheng’s lack of testing in this case because she examined the French Press; observed crack patterns, crack lines, and air bubbles that could conceivably support her conclusion about the combined effects of thermal and mechanical stress on defective glass; and cited scientific research to demonstrate that her theories are not so novel and unprecedented that real-world testing is required.
Case Details:
| Case Caption: | Pape V. Bodum USA, Inc. |
| Docket Number: | 1:23cv8401 |
| Court Name: | United States District Court, New York Southern |
| Order Date: | March 27, 2026 |
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