With May coming to a close, so is the bountiful harvest of fiddleheads and rhubarb ― early staples in Maine’s short growing season.

But for those who want to enjoy these crops after they’re no longer in season, they can join the growing number of people who are returning to traditional food preservation methods such as canning for use all year long.

“We have seen an increase in the demand for home food preservation education,” Kathy Savoie, a University of Maine Cooperative Extension educator, said. “A lot of [interest] lies in wanting to have greater control over knowing what is in the foods that they’re eating. And there is self sufficiency tied into it as well, having the satisfaction of knowing that they are able to meet their own food needs.”

Most people picture images of glass jars filled with pickled cucumbers and beans when think of food preservation, but freezing and drying fruits or vegetables are two other relatively simple ways seasonal foods can be preserved, Savoie said.

Savoie oversees the 10-year-old Cooperative Extension program that trains master food preserver volunteers. Equipped with the food preservation knowledge they learn through the program, volunteers act as community liaisons on the subject to broaden Cooperative Extension’s education outreach. With new grant funding in place for this program, this summer these volunteers will be stationed at food purchasing locations such as at farmers markets and community supported agriculture share pick up locations to educate shoppers on how they can preserve a portion of the seasonal produce they are buying for later use.

By giving consumers the tools to preserve food for future use, Savoie is hopeful this will positively affect local growers.

“[This] will help encourage consumers to purchase more and then freeze, dry, pickle, jam or jelly whatever they choose to,” Savoie said. “That will really boost sales for farmers.”

Regardless of whether folks are buying their produce while they are in season or growing and harvesting them themselves, Savoie said items should be preserved as soon as they have hit peak freshness to ensure the best possible quality. The Maine Federation of Farmers’ Markets has compiled a full list of produce items that are in season at any given point throughout Maine’s growing season.

Deciding whether to freeze or can a particular fruit or vegetable often comes down to personal preference, Savoie said, given that many items can be preserved both ways.

Canning works to preserve foods by using heat to kill any microorganisms that cause vegetables and fruits to spoil. By using proper canning techniques, heat forces air out of the jar, and as the jar cools a vacuum seal is formed which stops the the growth of microorganisms and preserves the food, according to UMaine Cooperative Extension.

However, when canning it’s important to use the proper method based on what type of food you are preserving. Low-acid foods must be canned using a pressure canning method to ensure the water temperature is high enough to kill the microorganisms, Savoie said. Things that have a high-acid content, such as jams, jellies, pickles and relishes, can be canned at the temperature of boiling water, but a pressure canner is required for canning fresh vegetables that were not preserved in another way before canning.

“They require a higher temperature to keep them safe and the high temperature is reached in a pressure canner, compared to a boiling water bath where things that are acidic are placed to processed,” she said.

While the shelf life of canned items varies based on the canning methods, generally they are safe for one year, Savoie said. However, food that has been preserved through freezing can be kept much longer, though the quality may waiver.

Berries are perhaps some of the most popular items to freeze when they are in peak during the summer. With strawberries coming into season between next month in July, to freeze them simply wash them, dry them and place them in an airtight container such as a freezer bag. This would be the same process with raspberries, blueberries and other seasonal fruits.

For vegetables, blanching in boiling water for a couple minutes before transferring to cold water improves the freezing quality. Savoie said greens such as chard and kale can be frozen after being blanched and work great for later use in soups and casseroles.

Berries that were frozen when fresh also can be used to make jams and jellies later in the season, Savoie said. However, she urged folks who wanted to can toward the end of the summer in September to stock up on canning supplies as early as possible, given that grocery stores often pull these supplies from their shelves later in the season.

While a less common form of preservation, the drying of produce using a dehydrator or home oven at a low temperature is also a way to preserve seasonal fruits. Savoie said this method is particularly great for hikers who want low-weight food or for use in granolas.

No matter the method you choose to preserve seasonal produce this summer, Savoie said the act of food preservation is a great way to enjoy local foods when they might not otherwise be available.