Value Village ／ Food & living
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Tofu is an everyday food far beyond Japan now, but it still prompts two questions: how long does it keep once opened, and why does it sit in water? Japanese supermarkets sell several kinds of tofu with different date labels, which is where the confusion starts. Here is how the types and the labelling system work.
| Type | What it is | Date while sealed | Once opened |
|---|---|---|---|
| Momen (firm) and kinugoshi (silken) tofu in a water pack | Sits in water | Use-by date (消費期限, shōhi kigen), a few days (3–7 days from manufacture) | Same day to the next day. Change the water in a clean container and refrigerate |
| Filled tofu (充填豆腐, jūten tōfu) | Soy milk and coagulant are sealed in the container, then heated. No water | Best-before date (賞味期限, shōmi kigen), a few weeks to 2 months (varies by product) | Same day to the next day once opened |
| Grilled tofu (yaki-dōfu), thick fried tofu (atsuage), thin fried tofu (aburaage) | Processed | Follow the label (a few days) | Use soon. Aburaage can be frozen |
| Kōya-dōfu (freeze-dried tofu) | Dry good | Several months to 1 year | Keep away from moisture |
[Verify] The date guidelines are general figures based on the labelling of the Japan Tofu Association and major makers. The label takes priority.
Changing the water every day does not stop the tofu itself deteriorating. Once opened, use by the next day. A sour smell, sliminess or cloudy water are signs to throw it away.
The basic method is to keep it in clean water in the fridge, which stops it drying out and protects the surface. Do not reuse the water from the pack; use fresh water.
Filled tofu is simply made differently: it is heated after sealing, which is why it keeps longer. The ingredients are basically soybeans, water and a coagulant, much the same as other tofu.
A use-by date (消費期限) is the limit for eating the food safely, and food past it is not recommended even if heated. A best-before date (賞味期限, used on filled tofu) is a quality guideline; if unopened and stored as instructed, it is often still fine a little past the date, but check its condition.
The texture changes, but there is a method: drain, freeze, thaw and use in simmered or stir-fried dishes. It takes on a meat-like texture, a money-saving and food-waste-reducing idea shared among people living in Japan.
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https://www.caa.go.jp/policies/policy/food_labeling/food_sanitation/expiration_date/
https://www.zentoren.jp/
https://www.mhlw.go.jp/www1/houdou/0903/h0331-1.html
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
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