A little heat is all you need to harness the woodland essence of thyme and infuse it into the oil of your choice. Infused oils are best used as a finishing ingredient, one reserved for drizzling over fresh baby greens or salumi. You can infuse any edible oil with herbs, but robust, aromatic oils, such as extra-virgin olive, overpower the mild nuances of thyme's flavor and aroma. Neutral oils, such as sunflower or canola, adopt thyme's essence and let it shine through crisply, and work best for infusion.
Rinse the thyme sprigs and spread them out on a plate lined with paper towels. You need about 3/4 cup of thyme sprigs per cup of oil.
Air dry the time overnight. Lightly muddle your whole bunch of thyme in a mortar and pestle.
Add the thyme sprigs and oil to a heavy-bottomed saucepan and place it on the stove. Set the heat to medium-low.
Monitor the oil temperature using an instant-read thermometer. Remove the saucepan from the heat when the oil reaches 180 degrees Fahrenheit.
Let the oil cool to room temperature. Strain the oil through a sieve and into a bowl, then transfer the oil to a glass bottle using a funnel. Store thyme oil in the refrigerator up to one month.
Although heating the oil to 180 F reduces some of the risks of bacterial growth from an herb infusion, it doesn't eliminate them. Botulism can occur in infused oils, so dispose of any oil that develops an off odor or color.