Most spice racks are in the wrong place. Above the stove, next to the window, in a drawer beside the oven. Heat and light are the two fastest ways to kill a spice's aromatics, and most kitchens put the spice rack right next to both. Here is what actually works, based on how we store stock at our Lourdes studio in Belo Horizonte.

Why heat and light are the main enemies

Spices contain volatile aromatic compounds, mostly terpenes and phenols, that give them their smell and flavour. These compounds evaporate at low temperatures and oxidise when exposed to light. A spice rack above a gas burner can reach 40 to 50 degrees Celsius during cooking. At that temperature, ground paprika loses a measurable percentage of its carotenoids every week. The fix is simple: a closed cupboard away from the stove, ideally on an interior wall where temperatures are stable.

Glass versus plastic versus tins

Glass is the best container for home storage because it is airtight when sealed properly and does not absorb odours. Plastic containers, even food-grade ones, are slightly permeable to volatile compounds over time. Tins are fine for whole spices but not ideal for ground ones because they are harder to seal airtight after opening. We use glass jars with rubber-sealed lids for all our stock, and we recommend the same for home storage.

How long do spices actually last

Whole spices: 18 to 24 months in a sealed jar in a cool, dark cupboard. Ground spices: 4 to 6 months before they start losing character noticeably. After that they do not become dangerous, they just get quieter. The test is simple: open the jar and smell it. If you have to put your nose right inside the jar to get anything, it is time to replace it. A fresh spice should hit you from 10 centimetres away.

The freezer question

Some professional spice buyers freeze whole spices to extend shelf life, and it works. The problem is condensation: every time you take a jar out of the freezer and open it, moisture enters. If you freeze spices, keep them in small quantities so you use a whole jar before putting it back. We do not recommend freezing for home cooks who open the same jar multiple times a week.

What to do with old spices

Do not throw them away immediately. Old whole spices can be toasted in a dry pan to revive some of their aromatics before grinding. Old ground spices work well in spice rubs for grilling, where the heat of the grill compensates for some of the lost volatility. They also work in slow-cooked dishes where the long cooking time extracts whatever is left. Save the truly dead ones for infusing oils or vinegars.

The simplest rule: buy less, buy fresher, store it in the dark. If you want to know when a new harvest lot arrives, the subscription box is the easiest way to stay current without having to think about it.