How long does mustard last in the fridge after opening?
Quick answer
- In the fridge
- Opened: a few months, up to 1 year
- In the pantry
- Unopened: 1–2 years; once opened, refrigerate it
Sources: USDA FoodKeeper, USDA FSIS: Food Product Dating, University of Wisconsin–Madison Extension: What's Up with Condiments?, Verbraucherzentrale (German consumer advice centers): Ketchup, mustard and other sauces (in German) · Last reviewed October 25, 2026
An opened jar of mustard keeps up to a year in the fridge, according to USDA FoodKeeper, and an unopened one keeps 1–2 years from purchase in the pantry. Germany's consumer advice centers are more cautious about opened sauces: kept cold and scooped with a clean knife, they usually last a few months. Mustard is very acidic (around pH 3 in tests cited by University of Wisconsin–Madison Extension) and resists spoiling, so an old jar may simply have lost its heat and aroma. The "best by" or "best if used by" date on the jar marks peak quality, not a safety cutoff. Homemade mustard is a different product and doesn't follow these numbers. When in doubt, throw it out.
How to store mustard
Until you open it, mustard is fine in a cupboard at room temperature, out of the light. After opening, the fridge is the place for it, whether it's yellow mustard in a squeeze bottle or Dijon in a jar. USDA notes that the "refrigerate after opening" line on the label is about quality rather than safety, and that cold storage keeps condiments fresh longer. The fridge door suits mustard well. What can spoil an opened jar is contamination: germs or food scraps carried in on a dirty knife. Even a well-kept jar slowly loses its heat and aroma.
- Keep unopened jars and bottles in a cupboard away from the stove and sunny windows.
- Once opened, put mustard in the fridge; the door shelf works fine for it.
- Scoop it out with a clean knife or spoon, never one that has already touched bread, meat or mayo.
- At cookouts and buffets, serve mustard in a small bowl and leave the jar in the fridge.
- Keep dry mustard powder tightly closed in the pantry for about 6 months, or in the freezer for 1–2 years.
Signs it has gone bad
- Mold on the surface, on the rim or under the lid: throw out the whole jar rather than scraping off the top.
- A yeasty, fermented or musty smell instead of the sharp smell of fresh mustard.
- A clear change in color, texture or taste compared with when you opened it.
- Mustard that barely stings anymore: its heat and aroma fade with time; that's a loss of flavor, not spoilage.
Frequently asked questions
Does mustard need to be refrigerated after opening?
For quality, yes. USDA FoodKeeper notes that the "refrigerate after opening" advice on mustard labels is there for quality rather than safety, and that refrigeration keeps condiments fresh longer. In the fridge, an opened jar keeps up to a year.
How long does mustard last once opened?
Up to a year in the fridge, according to USDA FoodKeeper. Germany's consumer advice centers give opened sauces, mustard included, a few months with cold storage and a clean knife, so check the smell and taste of a long-opened jar before using it.
Can you use mustard after the best-by date?
A "best if used by" date marks best quality, and USDA says foods that show no signs of spoilage may still be eaten after it. A sealed jar past its date may simply taste milder. Once it's open, go by smell, look and taste, and throw it out if you see mold.
Does mustard go bad?
It can. Germany's consumer advice centers say sauces like mustard are fairly resistant to spoilage because of their composition, but germs or food scraps carried in on a dirty knife can spoil them. Throw it out if you see mold or if its look, smell or taste has changed.
How long does dry mustard powder last?
USDA FoodKeeper gives dried ground mustard about 6 months in the pantry and 1–2 years in the freezer. Keep the container tightly closed so the powder stays dry.