Storage & shelf life
Tahini separated with oil on top — is it spoiled?
No — oil rising to the top of a jar or pail of tahini is normal, not a sign of spoilage. Natural tahini is stone-ground sesame paste with nothing added to keep it emulsified, so given time on a shelf, the oil separates out and settles on top, the same way it does in natural peanut butter or unfiltered olive oil left to sit. Stir it back in and it returns to a smooth, usable paste.
What separation does tell you is that the tahini hasn't been shaken or stirred in a while — it doesn't tell you anything about whether it's still good. The two are easy to mix up, especially for anyone used to processed nut butters engineered specifically not to separate.
Why it happens
Sesame seeds are roughly half oil by weight, and stone-grinding them into paste doesn't chemically bind that oil to the solids — it just suspends it. Gravity does the rest over time: the denser sesame solids settle, and the lighter oil migrates upward. Warmer storage speeds this along; cooler storage slows it, which is one reason some kitchens prefer to refrigerate opened jars.
This is expected behaviour for an unstabilized, minimally processed product, not a defect. A tahini that never separates at all is more likely to have added stabilizers than one that does.
How to fix it
- Stir thoroughly with a sturdy spoon or spatula, working from the bottom up, until the paste is uniform in colour and texture. It takes longer the first time a jar is opened than on later stirs.
- For an unopened jar that's been sitting a while, turning it upside down for a few hours before opening can help the oil redistribute more evenly and cut down on stirring time.
- For foodservice pails, a stick blender or paddle mixer speeds this up considerably over hand-stirring a large volume, and is worth it for anything beyond a small jar.
- Once stirred and smooth, reseal tightly — a well-sealed container slows how fast it separates again, though it will still happen eventually between uses.
Does the amount of separation mean anything about quality?
Not on its own. How much oil rises and how quickly depends on factors like the sesame's natural oil content, how finely it was ground, and how long the jar has sat since the last stir — none of which say much about whether the tahini is fresh or well made. A very oily-looking jar isn't necessarily lower quality than one with a thinner layer on top; it may simply be a batch from a higher-oil sesame or a longer stretch since it was last opened.
What's worth paying attention to instead is what's under the oil once it's stirred back in: the paste should turn smooth, pourable when warm, and free of grittiness. Genuine quality issues show up in texture and taste after stirring, not in how much oil happened to be sitting on top before you got to it.
What actually signals a problem — separation isn't it
Real spoilage signs in tahini are different from separation: a rancid or distinctly off smell beyond tahini's normal nutty, slightly bitter sesame aroma, visible mold, or an unusual colour shift. Any of those means discard it — but plain oil pooling on top, however dramatic it looks in a jar that's been sitting untouched, is not one of them.
Related questions
Is separated tahini safe to eat after stirring?
Yes — separation is a normal physical process in unstabilized sesame paste, not a sign of spoilage. Stir it back to a smooth consistency and use it as normal.
Why does some tahini never separate?
It's usually a difference in processing or added stabilizers rather than a difference in freshness. Traditional stone-ground tahini without stabilizers is more prone to separating than heavily processed versions.
Does refrigeration stop tahini from separating?
It slows the process considerably because cold temperatures reduce how freely the oil moves, but it doesn't stop separation completely over a long enough time. A firm stir before use is still the reliable fix.
Should the oil be poured off instead of stirred back in?
No — pouring it off removes flavour and fat that's meant to be part of the paste, and leaves what's left drier and harder to work with. Stirring it back in is the standard approach, not discarding any part of the jar.