Herbs contain volatile oils which can be used to replace salt as flavor enhancers. But in order for us to smell the aroma, the aromatic molecules need to be in a vapor phase. These oils evaporate readily at normal temperatures and pressures, which is why herbs smell so good when hung in our kitchens or placed in salads. When herbs are warmed, as in sauces or even in our mouths, more molecules are released as vapors, making the sensation stronger and the food more appetizing.
For herb lovers, the mint family, or Lamiaceae (or Labiatae), is the most eminent plant family of those with the strongly scented oils. Included among the 5,600 species of Lamiaceae are basil, mint, marjoram, oregano, rosemary, sage and thymeall part of our everyday selection of herbs. The active oil in mint is a remarkable substance called menthol. In On Food and Cooking Harold McGee says menthol raises the threshold temperature at which cold receptors in our skin begin to discharge. So our mouths feel cool, and a cool drink feels cold. This may account for mint's popular use as a complement to iced teas and other fun drinks.
In dry herbs, the cell structure is broken down, making it easier to extract more oils, and making them more potent. When cooking with dry herbs, recipes usually call for less. Still, most fresh basil enthusiasts will argue that the aroma of dried basil can never compare to the sweet complexity of fresh leaves which adds subtle hints of anise and mint. Because oils evaporate, over a period of time dry herbs will lose their flavor. Storing them whole rather than ground, and in air-tight containers, will extend their shelf life.
At 1:30 & 3:30 pm on Sunday, July 13 and Sunday, August 17, Carnegie Science Center's Kitchen Theater presents a public demonstration of cooking with herbs by Theodora Shipper, the owner of La Filipiniana restaurant on Butler Street. Shipper grows her own herbs to prepare her gourmet Filipino cuisine, and adds her herb selections just before serving to keep the aroma potent. Small quantities should be used at the start, to avoid over-flavoring. For a cool summer flavor she creates a house salad dressing that combines cucumbers, ginger and a combination of herbs.
Growing your own herbs, as she does, does not require a large space. Many types grow well in window boxes or large pots. Within the city, community gardens are a good place to grow herbs. Botany Hall at Carnegie Museum of Natural History has a display of a typical western Pennsylvania culinary herb garden, featuring 42 herbs, and pointing out that some are used medicinally or for fragrance. An herb garden is also featured at the Florence Lockhart Nimick Nature Center at Powdermill Nature Reserve.
Harvested herbs can be stored in many ways. Microwaving is a very handy way to store herbs. Shipper stores some by freezing. She washes and minces the fresh leaves, packs them in the individual compartments of an ice cube tray, adds a favorite broth or plain water, and freezes them. You can take one out whenever you need it.
Lynn Parrucci is program coordinator for the Kitchen Theater. Botanist
Susan Thompson also contributed to this article.
Visit the Kitchen Theater at Carnegie Science Center to learn more about
the science of cooking, and get a taste of what we're cooking and a recipe
to take home. For a schedule of daily cooking shows, check the schedule
board in the Science Center lobby on the day of your visit, or call 237-3400.
Be sure to ask if there is a guest chef appearing. The Kitchen Theater
at Carnegie Science Center is sponsored by the Jewish Healthcare Foundation.