Sourdough Baker Bridget Mariner to Share Benefits of Bread Baking at Quarry Hill

Bridget Mariner turned a pandemic-era kitchen obsession into Union Street Sourdough, and on Thursday, March 26, at 3 p.m., she brings that knowledge to the Anderson Inn as part of Quarry Hill's enrichment series for adults age 50 and better.

The free presentation will cover the science and philosophy behind Mariner's baking practice, including her use of 100% organic grains and extended fermentation times. According to a Quarry Hill news release, the discussion will touch on Maine's culture of creative self-sufficiency, the importance of ingredient sourcing, and why long fermentation makes a difference in the final loaf.

Central to the talk is a question many home bakers have wondered about: why does sourdough feel easier on the stomach than conventional bread? Union Street Sourdough's own materials point to the fermentation process as the answer. The long ferment breaks down phytates, compounds in whole-grain bread that normally block the body's absorption of calcium, iron, and zinc. Fermentation also reduces non-digestible carbohydrates in the wheat, which can make sourdough gentler for people with irritable bowel syndrome or mild gluten sensitivity, according to the bakery's website. On the glycemic index, sourdough scores a 54 compared to 71 for commercial bread, meaning it raises blood sugar levels more slowly than refined white bread.

The starter itself plays a role too. Sourdough starter naturally contains prebiotic and probiotic bacteria. While the heat of baking destroys most of the probiotics, the prebiotics survive and continue to support gut health in the finished loaf.

The Quarry Hill news release described Mariner's products as "lighter, flavorful, and accessible to those who struggle with conventional baked goods." Her bakery operates under three stated principles: organic grains always, long fermentation whenever possible, and a commitment to bread that is both delicious and more nutritious.

Mariner's path to professional baking followed a familiar pandemic arc. She came to sourdough during the lockdown years, building on what the news release described as "a lifelong love of baking," and eventually channeled that work into a bakery rooted in her community.

The event is free but requires advance registration. To reserve a spot, call Quarry Hill at 301-611-6 or email qhinfo@mainehealth.org.