Preserving berries and other fresh fruit is not rocket science, but if you're new to the art of canning, it can be a bit of a sticky wicket.
Those who don't follow the directions carefully — and don't understand the science behind the methodology — can blunder into all kinds of problem, from bland jams to overly runny textures.
And with today's emphasis on local, home-grown and sustainable foods, more and more home cooks and gardeners are turning to their grandmothers' day to learn ways to keep all that fresh-grown produce delicious and useful long after their backyard harvest is over.
"It's about experience and learning what works," artisan jam maker Elissa Rubin-Mahon told a dozen students at her natural-canning class at Relish Culinary Center in Healdsburg last month.
Rubin-Mahon's mom grew up on a farm in Minnesota, then moved to Southern California to raise her family. That's where Rubin-Mahon launched her lifelong quest to create high-flavor, all-natural jams.
"In Southern California, we had a massive Blenheim apricot tree, and we made preserves," she said. "Early on, I became aware of the difference between home canned and commercially canned products."
Along the way, Rubin-Mahon discovered a way to firm up the jam without the addition of pectin, a thickening additive. Her natural method involves applying high heat, very quickly, to small batches of fruit in order to preserve the natural flavor.
"It's a combination of sugar, fruit and acid, cooked to reach 220 to 225 degrees," she said. "I stop cooking at 220, because the flavor goes away after that. You want to cook as hard and fast as you can."
Without the interference of the extra pectin, the preserves come out boasting an intense flavor reminiscent of grandma's jam. Slathered on a piece of toast with butter, it doesn't get much better than this carefully cooked, slightly runny strawberry jam.
"Pectin came about with the advent of commercial jam-making," Rubin-Mahon explained. "It was developed as a short-cut method, but it compromises the flavor."
Working only in small batches under 7 pounds, Rubin-Mahon uses wild-crafted and rare heirloom fruit like Carnelian cherries to make jams for her own Forestville company, Artisan Preserves, which supplies places like Les Mars Hotel in Healdsburg.
She also serves as the master jammer for Quivira Vineyards in Healdsburg, creating unique preserves from the estate-grown fruit, such as figs and honey.
In addition to high heat and micro-batches, she uses a variety of fruit at the correct ripeness. Like wine and olive oil, the best jams come from some green fruit, most at 90 percent ripeness, and just a small amount of really ripe fruit.
"Mostly-ripe fruit holds its texture better, develops flavor as it cooks, and it has (natural) pectin and acid," she said. "You need to add acid for the pectin to work, and to get it to set, all you need to add is sugar."
During the class, Rubin-Mahon demonstrated her method of making strawberry preserves, one of the most memorable treats of her childhood.
"I love making strawberry jam, and the smell of it," she said. "I had an aunt who grew strawberries, and she would bring her jam, so I have a strong connection to it."
Of course, it's crucial to start out with high-quality fruit. Rubin-Mahon sources all her strawberries from Lou Preston of Preston Vineyards and Ranch in Dry Creek Valley.