How to Distill Peppermint Oil

Peppermint oil has many medicinal and therapeutic properties that make it one of the most popular herbs for making essential oils. The oil is extracted through a process called steam distillation, where water in one chamber is heated until it turns to steam and passes into another chamber containing the plant material. The plant material then releases oil that evaporates with the steam and travels through a tube. As the steam and oil cool back down to liquid in the condensing chamber, the oil separates from the water and forms a layer at the top of the water that can then be harvested.

Things You'll Need

• Fresh peppermint
• Colander
• Water
• Paper towels
• Steam distiller
• Collection jar
• Heat source
• Thermometer
• Storage containers

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Instructions

• 1

  Harvest your peppermint in the early morning just after the dew has dried off the leaves; this is when the oil is easiest to harvest. You want the plant to have bright green leaves. Try to harvest just before the plant flowers. Always use fresh plants to make the best oil. If you don't have peppermint growing in your garden at home, purchase fresh herbs from the grocery store.

• 2

  Wash the leaves with cool water in a colander and remove any that are brown or appear to have imperfections. The better the quality of the leaves, the better the quality of your oil. Lay them out on a paper towel and allow them to dry out of the sun.

• 3

  Set up your steam distillation still. Purchasing one can be expensive, so shop around or consider making your own. Remember that a proper still has three separate chambers and a cooling pipe probably made of copper or borosilicate glass, like that used in laboratories, and a heating apparatus such as a hot plate.

• 4

  Add water to the bottom chamber so that it is no more than two-thirds full and load the fresh herb into the middle chamber of your still. Stuff the middle chamber full for best results. The more plant material you have, the more oil you can produce. The entire plant can be distilled, but most people use just the leaves.

• 5

  Insert the copper or glass tubing that acts as the cooling chamber for the steam into the top of the chamber containing the plant material. Make sure that the end of the tube empties into a jar or another container to catch the water oil.

• 6

  Heat the water in the first chamber using a controlled heat source to about 212 degrees Fahrenheit or 100 degrees Celsius. As the water boils and turns to steam, it passes into the plant chamber and opens up the plant mass to release the oils, which evaporate with the water and pass through the tube to drip out the other side.

• 7

  Collect the drippings in a large jar. The majority of your oil is harvested in the first 10 to 20 minutes, while the rest may take several hours. In the collection jar, the water and oil separates so that the oil makes a thin layer across the top of the water.

• 8

  Separate the water and oil. The easiest way to do this is to use a collection jar that has an opening near the bottom that is plugged with a stopper. In this case, you can unplug the stopper and let the water drain into a glass bowl until the oil just barely touches the bottom of the jar and it is all you have left. Another option is to purchase a separating device, but again, these can be very expensive.

• 9

  Store your oil in a stopper flask or vial to be used at your leisure. Don't throw away the water. This is known as hydrosol and is water infused with the essential oil, meaning it smells like the herb and can be used as a spray or very mild form of the oil itself. Store it in a separate container.