Most people store fragrance in the worst room in the house and then wonder why a bottle they loved smells different two years later.
There is a number that settles the argument. For every 10°C rise in temperature, chemical reaction rates roughly double.
A bathroom that swings from 20°C to 30°C during a shower is not a slightly worse place to keep perfume. It is a place where the chemistry runs at roughly twice the speed, several times a day, for years.
The three enemies
Heat. Accelerates every reaction in the bottle, per the doubling rule above. The single biggest factor.
Light, and ultraviolet in particular. This one is faster than people expect. Direct sunlight can degrade a fragrance in weeks, and even indirect light from a window across the room does measurable work over months. One reported example, from industry stability guides rather than a journal we could read directly: a common fragrance material, trans-isoeugenol, can convert more than half of itself into its cis isomer after three months of daylight exposure. That is not the bottle fading. That is one material turning into a different material with a different smell.
Oxygen. Once a bottle is opened and part-used, the air in the headspace oxidises the contents. A half-empty bottle ages faster than a full one, and the first casualties are citrus, aldehydes and jasmine, which shift toward dull, sour or metallic.
Which of your bottles is most at risk
The families that go first are the ones built on volatile materials, which our notes and pyramid guide also covers.
Most vulnerable: citrus and aquatic. A fragrance like CK One or the original Acqua di Gio is exactly the profile that degrades first, because the things that make them what they are also evaporate and oxidise first.
Most durable: amber, woody and leather. Fragrances like Shalimar and Bandit are built on heavy, stable base materials and will outlast the fresh ones by years in the same cupboard.
Reported ranges, and treat these as rough because storage dominates: parfum commonly lasts six to eight years, EDP four to five, EDT two to three, with well-kept bottles going far longer.
So: the bathroom is the wrong place
Keep bottles in a drawer, a closet, or their original box, at ordinary room temperature, roughly 15 to 25°C.
One reported figure: fragrances kept in their original boxes retained around 94% potency after fifteen years in one study, reported secondhand rather than read by us directly, so treat it as indicative. Keep the box regardless. It is free light protection and most people throw it out.
Do not refrigerate unless you are storing something for years at a stable temperature. Cold is not the enemy; cycling is, and a fridge opened forty times a day is a temperature cycler.
Cold, and the question every Canadian asks
Someone asks us this every winter: will a bottle left in the car freeze.
No. Ethanol freezes at -114°C, and an alcoholic fragrance is roughly 70 to 90% alcohol by volume depending on the concentration. A Regina winter can hit close to -40°C in an ordinary cold snap. There is no Canadian winter that freezes a bottle of eau de parfum.
A warning about the numbers you will find if you go looking. Several sites publish a freezing point per concentration, along the lines of eau de parfum freezing at around -90°C because it is 15 to 30% alcohol. That figure is confused. The 15 to 30% is the fragrance oil content, not the alcohol content, and whoever wrote it first swapped the two. It gets copied. We are pointing at it because it is a clean example of how a number gets laundered into fact by repetition, which our how smell actually works guide covers from a different angle.
What cold actually does is nothing much, and then something. The liquid contracts, some heavier materials can drop out of solution and cloud the bottle, and the solution usually clears again as it warms. The damage, if there is any, comes from the cycle: cold garage, warm house, cold garage. Bring the bottle in and leave it in.
Do not spray a bottle that has just come in from deep cold. It will atomise badly, the top notes will be flat because they are not volatilising properly, and you will conclude the fragrance is broken when it is merely cold. Give it two hours.
Does perfume expire?
Not in the way food does, and the "three years" figure is misleading.
Sealed and well stored, a bottle commonly lasts three to five years and often much longer, with reports of good condition after a decade. You will not usually find a printed expiry date on a perfume box: under EU cosmetics rules, a product whose minimum durability exceeds 30 months does not have to print one at all, and perfume comfortably clears that bar. What the box carries instead is the little open-jar symbol with a period-after-opening figure, which is a convention about opened products, not a measurement of when a fragrance stops working.
How to tell a bottle has turned
Colour. Darkening toward brown in something that was pale.
The opening. Oxidation hits the volatile materials first, so a sour, sharp, vinegary or metallic first thirty seconds on something that used to be bright citrus is the classic sign. Our testing guide warns about department store testers for exactly this reason: a half-full tester under warm lights for months is a controlled experiment in everything we advise against above.
A flat drydown, where the structure has collapsed into just the base.
Cloudiness or sediment. Rarer than the other signs, and more serious when it shows up. A turned fragrance is generally not dangerous. It is disappointing, and it is the argument against buying vintage casually.
Decants and samples
They age faster, and we should say so plainly given what we sell.
A small vial has a high ratio of air to liquid, gets opened often, and travels in warm bags, so use decants within about a year, keep them out of sunlight, and do not leave one in a car.
The ratio is the whole story. A 2ml vial filled to 2ml still has a millimetre or two of air over the liquid, and by the time it is half used that headspace is a third of the volume. A 100ml bottle half used has the same proportion, but you opened the vial many more times to get there than you opened the bottle. Every opening swaps the headspace for fresh air, and fresh air is the oxygen supply.
Sprayer vials keep better than dab vials, and the reason is not delicacy. A dab vial means a wand or a fingertip going into the liquid and coming back out carrying skin oil, skin bacteria and whatever was on your hands. You are inoculating the sample. A sprayer never lets anything back in. See how decanting actually works for how we build ours.
Glass, not plastic. Fragrance is a solvent and it will slowly attack cheap plastics, pulling plasticiser into the liquid. If a sample arrives in a soft plastic vial, use it soon or move it. Aluminium atomisers are fine and are what most travel sprays are, because the interior is lined.
Our rule from the bench, which is about the material rather than the marketing: fill it, cap it, and stop admiring it. Every minute a decant sits open on a table during transfer is evaporation of exactly the lightest and most expensive part.
Batch codes tell you a bottle's age
Most houses stamp or print a code on the box and the bottle base. It is not an expiry date and it is not meant for you; it is a production reference so the house can trace a run. Free online decoders will convert most of them into a manufacture date, with the caveat that they are community-maintained and get houses wrong.
It is good for two things: telling you whether you are being sold an old bottle at a new-bottle price before you buy vintage, and letting you look for the same period again after you find a formulation you love, once the bottle runs out. Our guide to counterfeits and batch codes covers using codes to check a seller's story.
Write the code down somewhere that is not the box. The box is the thing that gets recycled during a move.
Travel, and the part that is safety rather than preference
Perfume is a flammable liquid. UN1266, Class 3. This governs how it moves, and how you pack it too.
In the car: never leave a bottle on a dashboard or in a glovebox in summer. A car interior in July runs far past the 10°C doubling threshold, and the contents are sealed glass.
Flying out of a Canadian airport, under CATSA's current carry-on rules, perfume goes in a container of 100ml or smaller, inside the single one-litre clear resealable bag you are allowed. CATSA flags a container over 100ml even when it is nearly empty, because the rule is written about the container, not the contents. A half-used 150ml bottle gets taken off you.
Separately from the security rule there is a dangerous-goods rule, and it is the one almost nobody knows. Under IATA's regulations a passenger may carry a total of 2 litres or 2kg of toiletry articles across carry-on and checked bags combined, with no single article over 500ml or 0.5kg. That allowance is cumulative and it counts your hairspray and your aftershave too. For a normal traveller it is unreachable. For someone moving a collection, it is the number that decides how much can fly at all, and airlines do enforce it when they notice.
Checked baggage takes larger bottles, inside that same total. Pack them in the middle of soft clothing, upright, in a sealed bag. Cargo holds are pressurised but they are cold, and a sprayer that has been jolted for hours leaks.
Posting it. Alcoholic fragrance is not ordinary mail. Canada Post will carry it only when it qualifies as limited quantity dangerous goods under the Transportation of Dangerous Goods Act, which means small inner containers, correct packaging, and the limited-quantity diamond marked on the outside of the box, and that route is open only to contract customers and business account holders, not to an ordinary person at a postal counter. Ground service only. Never air, never lettermail. Our guide to buying fragrance in Canada explains what that does to the Canadian market, and it is most of the reason a bottle can take over a week to cross this country when a book takes two days.
Do not mislabel a parcel to get around this. It is a safety rule with a reason, and it is the kind of thing that ends a business. It is also one of the most common pieces of bad advice on fragrance forums.
The maintenance programme
- Move everything out of the bathroom today. Biggest single improvement, and it costs nothing.
- Keep the boxes, or use a closed drawer.
- Buy the size you will finish inside two years. A big bargain bottle you use twice a month is oxidising faster than you are drinking it.
- Put your citrus and aquatic bottles at the front and use them first. Put the ambers and leathers at the back; they can wait.
- Note the batch code of anything you love, so you know what you are trying to replace.
Part of Nose to Bottle, our complete fragrance manual. Read it in order here.