Do spices expire, and why the printed date measures the wrong variable

1. 01

   FoodKeeper contradicts its own category rule by a factor of ten

   The category entries give whole spices 3 to 4 years, ground spices 2 to 3 years and dried herbs 1 to 2 years, but the named product entries in the same database run from 6 months for dried ground mustard to 5 years for whole sesame seeds. Ground cumin, ground nutmeg, garlic powder and onion powder each get 3 to 4 years, identical to a whole spice, while ground black pepper gets 2 years and cracked black pepper 2 to 3 (FSIS FoodKeeper). The spread is the finding: no category rule survives contact with individual products.

2. 02

   None of these dates is a safety line

   Every FoodKeeper spice window is identical before and after opening, the signature of a quality metric rather than a hazard metric (FSIS FoodKeeper). A dried spice sits at a water activity the trade keeps at 0.75 or below, and Salmonella needs 0.94 in food generally and 0.979 plus or minus 0.003 in ground black pepper at 35 degrees Celsius before it will grow (FDA). Nothing multiplies in a dry jar. What the timeline predicts is the point at which the aroma fraction has fallen far enough that the spice stops working.

3. 03

   Grinding multiplies surface area roughly twentyfold

   Volatile loss happens at the solid-air interface, so the rate scales with exposed area. A 4 mm peppercorn carries a surface-to-volume ratio near 1.5 per mm; ground to a 200 micrometre powder the same material sits near 30 per mm, about twenty times the area for evaporation and oxygen ingress, and grinding also ruptures the oil cells that were holding the fraction inside intact tissue. That geometry is the physical content of FoodKeeper's split between 3 to 4 years whole and 2 to 3 years ground (FSIS FoodKeeper).

4. 04

   The measured five-month loss is 12.7 percent, not the collapse people assume

   Dry whole hot pepper pods stored in jute or low-density polyethylene at 20, 25 or 30 degrees Celsius and sampled every 50 days to day 150 lost, on average, 22.6 percent of ascorbic acid, 19.0 percent of phenolic compounds, 17 percent of carotenoids and 12.7 percent of capsaicinoids, retaining between 77.4 and 87.3 percent of initial amounts (Iqbal et al. 2015). Losses were steeper at the higher storage temperatures and steeper in jute than in polyethylene, which states the temperature and barrier argument as data.

5. 05

   A year in a glass jar converts terpenes rather than simply losing them

   Essential oils from black, green and white pepper stored for 1 year in a glass vessel at room temperature yielded less oil overall, a lower terpene content and a higher proportion of oxygenated terpenoids (Orav et al. 2004). The composition shifts rather than thinning out, which is why an old jar smells flat and slightly resinous instead of weaker. The same study found sublimation-dried green peppercorns at 12.1 mg oil per g against 0.8 mg per g air-dried, a fifteenfold processing effect that dwarfs storage.

6. 06

   Light does something heat does not, and darkness is nearly free

   Coriander seed essential oil stored for one year in the dark showed only minor compositional changes and organoleptic properties that were virtually unchanged, while the same oil stored in the light underwent significant chemical transformation of its monoterpenes (Misharina 2001). Same molecule, same duration, different outcome, decided entirely by exposure to light rather than by time or temperature. That is the argument against decorative clear glass on an open rack, and the argument for the opaque tin that commercial spice packers already use as standard.

7. 07

   Piperine and capsaicin are the stable actives because they are not volatile

   Both are high molecular weight non-volatile alkaloids sitting outside the essential oil fraction, and capsaicin melts near 62 degrees Celsius with no meaningful vapour pressure at cupboard temperature. Capsaicinoids were the most stable class measured over 150 days at 20 to 30 degrees Celsius, at 12.7 percent loss (Iqbal et al. 2015). For piperine the mechanism is identical but the measurement is missing: a controlled series tracking piperine and volatile oil in the same ground pepper over 24 to 36 months at a stated temperature is what would settle it.

8. 08

   Curcumin is the light-sensitive extreme, with a 9.9 hour half-life under a white LED

   Turmeric oleoresin exposed to fluorescent light or a white LED at 10 W per square metre degraded with curcumin half-lives of 15.1 hours under fluorescent light and 9.9 hours under white LED, against 18.1 and 11.7 hours for demethoxycurcumin and 18.4 and 13.2 hours for bisdemethoxycurcumin, while the dark control at 25 degrees Celsius held (Kim et al. 2025). Curcumin, the most abundant curcuminoid, went fastest. Those are laboratory irradiances rather than shelf conditions, but the direction applies to any transparent container in the open.

9. 09

   Paprika and chilli are the only real case for the refrigerator

   Paprika stored at 4 degrees Celsius and 70 percent relative humidity, with no reconstitution of its antioxidants, showed carotenoid autoxidation occurring only minimally and coloring capacity maintained, with peroxide values starting at 1 milliequivalent per kg and reaching only 3 at the end of storage (Perez-Galvez et al. 2009). Ambient storage does not manage this: carotenoids fell 17 percent over 150 days at 20 to 30 degrees Celsius (Iqbal et al. 2015). A paprika that has turned brown is reporting its own condition accurately.

10. 10

    The rack above the stove fails on heat, light and water at the same time

    Convection puts the burner plume onto whatever is mounted above it, task lighting makes that spot the brightest in the room, and a pot at a rolling boil is a steam generator. FDA states the third mechanism directly: ground black pepper can become wet during food preparation in a home or restaurant when exposed to steam or humid air (FDA). What would make the case quantitative is a headspace temperature and humidity trace from a jar above a working range across a real cooking session, against a control in a closed drawer.

11. 11

    The measured hazard is 6.6 percent Salmonella and 12 percent filth at import

    FDA sampling of imported spice shipments across FY2007 to FY2009 found an average Salmonella shipment prevalence of 6.6 percent on a 750 g sample, 95 percent CI 5.7 to 7.6 percent, 1.9 times the rate for other FDA-regulated imported foods and 4.4 times under a matched protocol, with 79 countries examined and 37 producing contaminated shipments. Filth adulteration ran at 12 percent, 95 percent CI 10 to 15 percent, mostly insect fragments, whole insects and animal hair, nearly all of them stored product pests (FDA).

12. 12

    Cooking solves it, and 70 percent of the illnesses came from where it does not

    Fourteen outbreaks were attributed to pathogen-contaminated spice from 1973 to 2010, producing 1,946 illnesses, 128 hospitalizations and two deaths, with Salmonella responsible for ten outbreaks and 87 percent of illnesses. Consumption of ready-to-eat foods prepared with spices applied after the final manufacturing pathogen reduction step accounted for at least 70 percent of the illnesses, and in three of four outbreaks with process data, no pathogen reduction treatment had been applied (FDA). Finishing blends, dusting and uncooked dips are the exposure, not the simmering pot.

13. 13

    Clumping means water got in, and mould is the only real discard trigger

    Salmonella survives in low-moisture material for periods exceeding one year without growing, and needs a water activity of 0.94 in food generally, or 0.979 plus or minus 0.003 in ground black pepper at 35 degrees Celsius, before it multiplies; the spice trade stores at 0.75 or below (FDA). Pepper sitting near the growth threshold may not be noticeably wet (FDA). Caking is the visible sign that particles bridged because water entered. Visible mould means water activity stayed high long enough to support growth, and that jar goes out.

What people ask us next.

Q01

Do spices actually expire?

Not in the sense of becoming unsafe. FoodKeeper gives whole spices 3 to 4 years, ground spices 2 to 3 years and dried herbs 1 to 2 years, and the window is identical before and after opening, which marks it as a quality figure (FSIS FoodKeeper). What degrades is the volatile oil fraction: after 1 year in glass at room temperature, pepper samples yielded less oil, less terpene content and more oxygenated terpenoids (Orav et al. 2004). Nothing grows in a dry jar, because Salmonella needs a water activity of 0.94 and the trade stores spice at 0.75 or below (FDA).

Q02

How long do spices really last?

It depends on the product, and FoodKeeper's own entries prove it. Whole sesame seeds are listed at 5 years, ground cumin, ground nutmeg, garlic powder and onion powder at 3 to 4 years, cracked black pepper at 2 to 3 years, ground black pepper and chili powder at 2 years, seasoning blends at 1 to 2 years and dried ground mustard at 6 months (FSIS FoodKeeper). That is a tenfold range inside one dataset. Use the named entry where one exists, buy whole and grind to order for high-terpene seeds, and treat blends as the shortest-lived items in the rack.

Q03

Is it safe to use spices past the date on the jar?

Yes, absent mould or caking. The date is a quality estimate and dried spice does not support microbial growth: the water activity threshold for Salmonella is 0.94 in food generally and 0.979 plus or minus 0.003 in ground black pepper at 35 degrees Celsius, while trade storage guidance sits at 0.75 or below (FDA). Salmonella can survive over a year in low-moisture material without multiplying, so an old contaminated jar is no more contaminated than a new one (FDA). The failure mode of an old spice is that a recipe written for a fresh one underdelivers.

Q04

Should spices be kept in the refrigerator?

Only the carotenoid-pigmented ones, and paprika is the clear case. Paprika held at 4 degrees Celsius and 70 percent relative humidity without antioxidant reconstitution showed carotenoid autoxidation occurring only minimally and coloring capacity maintained, with peroxide values of 1 milliequivalent per kg rising to only 3 by the end of storage (Perez-Galvez et al. 2009), against a 17 percent carotenoid loss over 150 days at 20 to 30 degrees Celsius in ambient storage (Iqbal et al. 2015). For everything else the fridge adds condensation risk on every door opening, and moisture is the variable that matters (FDA).

Q05

Is the spice rack above the stove really that bad?

It is the worst position in the kitchen because it fails on three variables simultaneously. It receives the burner convection plume, so it runs hottest, and losses in the storage trial were steeper at 30 degrees Celsius than at 20 (Iqbal et al. 2015). It is usually the brightest spot, and coriander oil stored in the light underwent significant monoterpene transformation while the same oil in the dark was virtually unchanged after a year (Misharina 2001). And FDA states that ground black pepper can become wet during home or restaurant food preparation when exposed to steam or humid air (FDA).

Q06

Do whole spices really last longer than ground?

Yes, and the mechanism is geometry. Volatile loss occurs at the solid-air interface, so the rate scales with exposed surface area. A 4 mm peppercorn has a surface-to-volume ratio near 1.5 per mm; ground to a 200 micrometre powder that rises to about 30 per mm, roughly twenty times the area, and grinding ruptures the oil cells that were retaining the volatile fraction. FoodKeeper reflects this at 3 to 4 years whole against 2 to 3 years ground, and puts cracked black pepper at 2 to 3 years against 2 years for fully ground (FSIS FoodKeeper).

Q07

Can old spices make you sick?

Age is not the risk factor; contamination at source is, and it does not increase with time in a dry cupboard. FDA found an average Salmonella prevalence of 6.6 percent in imported spice shipments across FY2007 to FY2009 on a 750 g sample, against under 1 percent for all 11 spice types tested at US retail on a 125 g sample between 2013 and 2015, with no positives for cumin, whole sesame seed or ground white pepper (FDA). Fourteen outbreaks were recorded from 1973 to 2010, and at least 70 percent of those illnesses came from ready-to-eat foods spiced after the final pathogen reduction step.

Q08

When should a spice actually be thrown out?

On evidence of water, not on a date. Visible mould is the only genuine discard trigger, because it means water activity stayed above the growth threshold long enough to support a colony; the reference thresholds are 0.94 for Salmonella in food generally and 0.979 plus or minus 0.003 in ground black pepper at 35 degrees Celsius, against trade storage at 0.75 or below (FDA). Hard caking is the earlier warning that water entered, and pepper near the growth threshold may not look wet at all (FDA). Everything else is a potency judgement: crush a pinch and smell it immediately.