Is Zojirushi thermos dishwasher safe?
Sometimes — the stainless steel body is dishwasher safe, but the lid assembly (including the gasket and inner cap) should be hand washed to prevent seal degradation and decal peeling.
Quick facts
| Dishwasher safe? | Sometimes — Sometimes — with care |
|---|---|
| Category | Drinkware |
| Source | AI-reviewed · manufacturer guidance & material science |
| Last checked | 2026-07-28 |
Why
Zojirushi thermoses are primarily made of stainless steel (body) and polypropylene/ABS plastic (lid). The stainless steel body is dishwasher safe; it can withstand high heat and alkaline detergents without rusting or warping. However, the lid contains a silicone gasket that can degrade over time due to heat and detergent, leading to loss of vacuum seal. The plastic parts may warp or become brittle, and printed markings (e.g., logos, measurement lines) can peel off. Zojirushi's official care instructions explicitly state that the lid and gasket should be hand washed, while the body is top-rack dishwasher safe. Repeated machine washing of the lid can cause the gasket to harden, crack, or lose elasticity, resulting in leaks and reduced insulation performance. The body may also develop minor water spots or clouding from hard water minerals, but this is cosmetic and does not affect function.
How do you wash Zojirushi thermos?
- Disassemble the lid by unscrewing the inner cap and removing the silicone gasket.
- Hand wash the lid, inner cap, and gasket with mild dish soap and warm water using a soft sponge.
- Rinse all parts thoroughly to remove soap residue.
- Dry the lid components completely with a soft cloth before reassembly.
- Wash the stainless steel body by hand with soap and water, or place it on the top rack of the dishwasher (if desired).
- For stubborn stains or odors inside the body, use a mixture of baking soda and water or a dedicated stainless steel cleaner.
- Reassemble the lid only after all parts are completely dry.
What happens if you put Zojirushi thermos in the dishwasher?
If you put the entire Zojirushi thermos in the dishwasher, the most immediate effect after one wash is likely cosmetic: the printed logo or measurement lines on the lid may start to peel or fade. The silicone gasket may become slightly swollen or misshapen, but it might still seal temporarily. After repeated washes (5-10 cycles), the gasket will harden and crack, causing the lid to leak when the thermos is tipped. The plastic lid may warp, making it difficult to screw on or off. The stainless steel body may develop water spots or a dull finish, but this is cosmetic. Functionally, the loss of vacuum seal is the most critical failure: the thermos will no longer keep contents hot or cold for extended periods. The damage is permanent; replacement parts (gasket, lid) may be available, but the body remains usable.
Frequently asked questions
- What water temperature can the Zojirushi thermos withstand?
- The stainless steel body can handle boiling water (212°F/100°C) and can be used for hot beverages. The lid plastic is rated for up to 212°F, but prolonged exposure to high heat may cause warping.
- Will the coating peel over time?
- Zojirushi thermoses typically have a powder-coated exterior on some models. This coating can chip or peel if scratched or exposed to harsh detergents, but it is not common with normal hand washing.
- How often should the gasket be replaced?
- The silicone gasket should be inspected every 6-12 months. Replace it if it becomes hard, cracked, or no longer seals tightly. Replacement gaskets are available from Zojirushi.
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Last updated 2026-07-28. General guidance — always check your product’s care label. How we verify · Dishwasher care guides.