How to Make Peppermint Essential Oil

Collect good-quality peppermint leaves without any bruising, wilting or brown spots. Look for large dark-green leaves on the top third of the plant. If you are able to find wild peppermint or you grow your own, the best time of day to collect leaves is early morning, when the plant oils are their strongest. Otherwise, peppermint leaves sold at grocery stores and farmers' markets work well to make the oil.

Place the peppermint leaves in a colander and gently spray with cool water. Spread the leaves on a clean kitchen towel and let them air-dry.

Crush the peppermint leaves gently with a mallet or mortar and pestle to release the oil. If you're using a mallet, place the leaves on a cutting board or counter, and gently tap the leaves. If you're using a mortar and pestle, place the leaves in the mortar, or bowl, and gently press the leaves with the pestle. The leaves should be slightly bruised and have a strong peppermint smell. Do not grind the leaves up or over-pound with the mallet.

Fill the glass jar with as many peppermint leaves as it will hold, then fill the jar with carrier oil until all the mint leaves are submerged. Tightly seal the jar, and give it a small shake to ensure that the leaves are fully covered by the oil.

Leave the sealed jar on the counter, out of direct sunlight, for 24 to 48 hours so the peppermint leaves can steep in the carrier oil.

With the clean glass jar underneath, carefully pour the oil through a cheesecloth or fine-mesh strainer. The used leaves should remain in the strainer while the oil pours into the glass container. Discard the used mint leaves. Store the sealed jar of peppermint essential oil in a cool, dark location -- such as a pantry -- and use within 4 to 6 months.