Curriculum Connections

Rottin' Lessons
Before launching into food-drying activities, consider engaging your students in predicting and observing what happens to harvested garden produce over time. They might leave different items out on a table in the garden or classroom, for instance, and make daily observations and drawings of changes that occur. (Or they could compare a fruit or vegetable in its fresh and dried states, side by side.) Ask, What changes did you notice? Was there evidence of other organisms (e.g., mold or fruit flies)? Did some types of produce rot or dry out more quickly than others? What were the conditions (light, heat, and so on) where the produce sat? How might you explain your findings? Challenge the class to try to prolong a new item's freshness by choosing new location or conditions.

Kitchen Sleuths
Ask students to examine their kitchens and/or grocery stores for evidence of dried foods. (You may want to have younger students start with a group brainstorm, or simply bring in some dried fruits to examine.) Encourage students to think beyond the obvious items, such as raisins, to other products, such as dehydrated potatoes, noodles, or powdered soup mixes. Students can classify their collection as they see fit and then chart what they see as advantages and disadvantages, in each category, of the dried food versus its fresh counterpart. They might consider such factors as flavor, cost, longevity, weight, and so on.

You might extend this investigation by asking students to again scope out their kitchens and generate a list of foods they think have been preserved in some way (e.g., pickling, smoking, canning, chemical preservatives, fermenting, freezing.) Consider sharing some of the information from Preservation 101, below. Have them list how they think each type of food they've listed has been preserved. (A food may be preserved by multiple means. Vegetables, for example, may be canned and contain chemical preservatives.)

In a Pickle Over Harvest Gifts?

Invite your class to create gifts or products to sell from foods they've dried or preserved in other ways. A simple jam-making or pickling project can integrate math skills and chemistry lessons (e.g., testing pH of pickle solutions or exploring the role of sugar as a preservative). As students create labels or ads and market their goods, you can weave in economics, art, and language arts lessons. Canning projects also illuminate physical science concepts related to air pressure. (When full canning jars are heated, air is driven out; when cooled, the pressure in the jar decreases and the jar seals.) Following are a few easy "recipes" to get you started. For more details on pickling, canning, and drying projects, see the Related Articles and Resources sections.

Mint Tea Packets
Have students locate and dry the following herbs or create their own recipe (which might feature just one herb) and crumble them for tea. Place the mixture in jars or sealable plastic bags. Make decorated labels with brewing directions: Steep 1 tablespoon in a cup hot water for 1 to 3 minutes.

3 tablespoons peppermint leaves
1 tablespoon catnip leaves
1 tablespoon lemon verbena leaves

Fragrant Sachets
Students can create small cloth drawstring bags (or mini-pillows) filled with dried herbs and flowers to help drawers and closets smell fresh. A spicy concoction might feature dried leaves of basil, sage, lemon verbena, and thyme. A floral mixture could contain dried flower petals from carnations, gardenias, geraniums, lavender, jasmine, roses, orange blossoms, and/or sweet peas.

Easy Berry Freezer Jam*
2 cups berries
4 cups sugar
1 package pectin (powder)
cold water

Rinse and drain berries. Remove stems and crush them in a mixing bowl. Add sugar, mix, and let stand for 10 minutes. Dissolve the pectin in a bit of cold water. Bring the raspberries and sugar to a full boil for 1 minute, stirring constantly. Pour in the pectin solution and once the mixture again reaches a full rolling boil, stir it for 2 minutes. Pour the jam into plastic containers, leaving ½ inch of space at the top to allow for the jam to expand. Cover the containers and let them stand at room temperature for 24 hours. Enjoy the results immediately and/or give them as gifts. (They'll keep up to a few weeks in the refrigerator or a year in the freezer.)

* To preserve jams in canning jars so they'll be longer lasting, try the recipe in the article, Making Jewel-Toned Jams.

More Harvest Gifts
Consider engaging your students in finding or creating recipes for the following preserved harvest products, then packaging them for sale or gifts: pickled cucumbers or beans, dried soup or stew mix, fruit compote mix, herb blends for dips, pasta sauce mix (made from dried tomatoes, peppers, and herbs).

Preserving Community/Cultures
Invite students to visit ethnic groceries, conduct interviews, and do library and Internet research to explore food preservation in their communities. Students might generate questions and then interview families or community members to learn if and how they preserve foods. They might ask about canning (pickles, jams, chutneys, and so on), freezing, drying, making meat jerky, smoking, salting, root cellaring, or fermenting. Which preservation methods or products are unique to different ethnic or cultural groups? If students also interview seniors and conduct research, they can explore how food preservation has changed over time. Which types of foods comprised the diet of your community 100 or 200 years ago? How were the foods preserved? Did peoples' diets change with the seasons? Using recipes gathered through their interviews and research, the class might design and create its own "preserving the harvest" cookbook.

Harvest History: The Roots of Preservation

Challenge your students to explore the roots of food preservation with these types of questions in mind: What might have prompted early people to find ways to preserve foods? How might their needs compare with ours today? What methods were used by different cultures and regions? What affect might these approaches to food preservation have had on a culture's economics, technologies, and lifestyles? Consider sharing some of the following information to inspire students' investigations.

A Brief History
For more than 12,000 years, humans have been preserving foods in various ways. In fact, humans' ability to produce and preserve food was a tremendous advance in the history of civilization. Our early ancestors moved from place to place in search of fruits, nuts, berries, and other plant parts and wild animals. When times and weather were good, they feasted, but other times were lean. Once humans began growing food, they stayed put, but they still needed food to survive beyond the growing season and during other times of scarcity. After all, refrigeration was a long way off! Through trial and error, early humans learned (sometimes the hard way!) which methods helped food last longer. Their finds? Drying, freezing, fermentation, and using substances such as salt, herbs, and spices.

Native Americans dried corn and beans in the sun, while early Chinese and Italians dried starchy noodles. Japanese families hung persimmons on lines to dry in the fall. Colonial Americans pushed apple slices on broomsticks to dry for storage. Indigenous South Americans carried potatoes into the Andes Mountains, crushed them to a pulp, then left them to freeze on a rock overnight. The cold, dry air and high altitude (low pressure) produced one of the first freeze-dried foods! Fermented (alcoholic) beverages were consumed by the earliest civilizations of Mesopotamia and Egypt. Some early cultures preserved or "pickled" foods with a fermented product, vinegar. In tropical areas, spices, many of which can kill bacteria, were often used (in curries, for instance) to keep foods from rotting.

Preservation 101

Successful food preservation often involves combining at least two of these basic methods. Pickling, for instance, involves the use of vinegar (a fermented product with a low pH) and heat to preserve vegetables.

Drying - This prevents meat and produce from rotting and stored seeds from sprouting. It also inhibits the growth of microorganisms while the food is dry.

Heating - Heat can increase shelf life by temporarily sterilizing food.

Freezing - Frozen foods remain in edible condition almost indefinitely.

Fermentation - Fermentation is a gradual chemical change caused by the enzymes of some bacteria, molds, and yeasts. It is used to produce bread, vinegar, cheese, alcoholic beverages, and yogurt.

Chemical preservation - Humans have used chemical preservatives for millennia. Salt was extremely precious in ancient times, in part because it was a great preservative for meat and other foods. Smoking is another ancient and common means of chemical food preservation. Spices are rich in antioxidants and substances that kill bacteria.

Irradiation - A more recent technology, irradiation, is used to destroy microorganisms on many spices and is increasingly used on fruits, vegetables, and berries. (Students might want to investigate different sides of the controversy surrounding irradiated foods.)

 


Preserving the Harvest
Contents

Dehydrating Food

Background

Materials

Simple Drying Methods

Constructing a Solar
Food Dehydrator


Curriculum Connections

Rottin' Lessons

Kitchen Sleuths

In a Pickle Over
Harvest Gifts?

Preserving Community
Cultures

Harvest History:
The Roots of Preservation


Resources

Web Sites

Harvest Preservation
Items from our Store


Related Articles

Pickling Cucumbers

Canning and Freezing
Root Crops

Drying Tomatoes

 Jewel-Toned Jams

Safety Caution! Bacteria and mold can grow in foods that are incompletely dehydrated. Err on the side of caution and over dry the food rather than leave too much moisture in it.

Conditioning. To prevent mold growth during storage, you must condition food first. This equalizes the moisture content throughout the pieces of dried food. Pockets of moisture in stored foods are sites where toxic molds and bacteria can grow.

To condition dried food, put it in a clear container on a cool, shady shelf for one week. Check container daily; if moisture condenses on the inside, the food is not fully dehydrated. Return it to the dehydrator for another round, or heat pasteurize it.

Pasteurizing. You can use either of these methods to pasteurize dried food:

1. Deep Freeze. Place food in freezer bags, and store for 48 hours in a freezer set at 0°F.

2. Heat Treatment. Preheat oven to 160°F. Spread produce no more than 1 inch deep on a cookie sheet and heat in oven for 30 minutes.