What to do with all your old spices

They may be past their prime, but that doesn’t make them useless.

bowls full of spices
Your year-old spices aren’t done yet.Andra Ion via Unsplash

Now that the great cooking season is behind us, and spring cleaning is nigh, you've got your eye on the pantry, which is full of dry mustard powder and paprika of dubious age and origin. But your stash likely doesn't need to meet the compost pile pile just yet. They've still got some uses, especially around the house.

When to throw away your spices

Spices (the root, seed or non-leafy bits of a plant) and herbs (the leaves, flowers, and stems) spread small amounts of the chemical compounds they contain into your food. These are volatile, in the chemical sense, meaning they change phase states easily. Once a spice is harvested, the clock begins ticking as those compounds turn to from liquids to gas. While it certainly depends on the spice, you'll notice a loss in potency after roughly a year, and by three years in, they'll need replacing.

What to do with less-than-fresh spices

That said, year-old spices aren't done yet. Like for many chemical reactions, adding heat can transform your product, enhancing the smell and taste. Try throwing spices about a year or so old on the grill or in a dry pan right before using them. Toasting spices is an age-old hack, and is key to capturing the flavors of some cuisines. Before you decide to make use of them elsewhere, give them a toast and see if they're still alive.

You could also infuse oils. Infusions draw the compounds out of a spice or herb. Seal your spices in the oil for two to six weeks, then filter out the solid matter. Grind the spices finely before doing this, and for older spices, you may want to put the jar with your oil in a simmering water bath for a few minutes. As mentioned earlier, adding heat helps. For personal care or crafting supplies, use shelf-stable oil like jojoba. For cooking, use an oil you like to eat.

You could also try to grow the plants from which your spices came. Several common spices, like juniper, grow in temperate areas, so if you've got some seeds, you can plant them in pots to see if they'll grow.

Spices and safety

Before taking spices outside the kitchen, make a point of familiarizing yourself with potential allergies. We generally consume very small amounts of the compounds contained in herbs and spices, and as we up the dosage, the risk of allergic reactions rises as well. (The "cinnamon challenge" was even more stupid than it looked.) So if you're planning to use up your spices for skincare products or scent diffusers, there are a few important things to note:

Know your herbs and spices. Search any herb or spice you plan to use in the Household Products Database to ensure there's no major allergy risk or other potential injury.

Remember that food allergies may not translate to skin allergies and vice versa.

Don't assume heat will solve the issue. Some allergens, like celery seed, are heat stable.

Eating something is different from long-term contact with it. Check that the spices or their compounds aren’t a problem if they linger in your environment.

Extract the smells from your old spices and herbs

Despite what people think, there's no evidence that any spice drives away pests. And despite claims that you should throw black peppercorns in the laundry, you probably shouldn't. (I believe the idea is that the peppercorns will grind stains off, but even if that were true, and it isn't, you could get the same results with other household abrasives.) There are, however, a few legit ways to use your old spices around the house.

Spices are a useful weapon against bad smells if you don't have time to get rid of the underlying causes. Your grandmother may have done it with potpourri, which is still an option, but if you're not quite ready for grandma-hood, there are a few other methods.

If you're cooking something strong in the kitchen, clear it out afterwards by boiling some oil spices in water. Volatile compounds have a low boiling point, so large amounts of old, bland spices will have a surprising amount of smell to them. Afterward, drain the water and put them out to compost.

For clothes and books, create sachets full of old spices that can give off their smell over time. This is particularly useful if you choose the right spice for the right clothes. For example, spices like cinnamon trick our minds into thinking it's warmer than it is, so fill sachets with warming spices like cloves and cinnamon to put with your winter clothing. For summer clothes, try dried mint, coriander, or other spices that taste "cool" to you.

You can also throw these sachets in with stinky clothes such as inside old socks or in shoes when you can’t wash them right away. Include something absorbent as well, such as baking soda, to help tamp down the reek until you can get them into the laundry.

This will also work with carpets. Instead of buying carpet freshener, you can mix baking soda and your spices in a ratio of two parts baking soda to one part spices, shake it over your carpet, and vacuum it up after a few minutes. Ensure the spices won’t stain your carpet before you sprinkle.

Crafts to use up your spices

If you’re a crafty sort, spices are incredibly useful. Dried whole herbs can be used on their own as decoration, and can remain fragrant for a surprisingly long time. But don’t stop there.

Spices were the coloring agents for the first paints and you can easily do the same with your more vibrant spices. Mix together one cup of flour, 1.25 cups of cold water, and a tablespoon of neutral oil until it's thick enough to paint with. Divvy it up into as many containers as you like and then mix in different colorful spices. These paints are kid-safe and smel good, making it a useful project for distracting the family while you clean the kitchen. Some spices, like tumeric, can also be used as dye.

If you dislike the smell of vinegar, add a small amount of spices to your homemade cleaners to give it a lift. You can spice up your candles as well, using the infused oils we’ve described above. Just pour them in with the liquid wax.

Spices have been used to give soaps smells and textures for hundreds of years. If you just want a I-paid-$24-for-this-on-Etsy look, you can leave them whole on top of the bar, but to get their smell into the soap, you’ll need to grind them finely before adding them into the soap batter.