Grandma’s Hands

Sourdough bread

Do grandmas really have a “magic touch” for baking?

This is Sandra Tsing Loh with the Loh Down on Science.

Aspen Reese from Harvard wanted to know: can grandma’s actual hands really make a difference?

She and her team sent flour to eighteen bakers across North America and Europe. The bakers used that flour to make some sourdough starter.  After flying everyone to Belgium, researchers took DNA samples from the starters — and the baker’s hands!

They compared these samples to find different types of microorganisms like bacteria and yeast. Surprisingly, over a quarter of the species of microorganisms in the starters came from the bakers’ hands!

After the analysis, the bakers baked their bread. Then some lucky judges did a taste test. Yum!

Results? Despite having different microorganisms from the different bakers, the breads tasted — about the same. Why? Reese thinks it’s probably because most of the flavor-producing microorganisms came from the flour, NOT the bakers’ hands.

Doesn’t explain the failure of MY pandemic sourdough starter. Oh well, on Instagram, no one knows WHOSE hands made the bread!

Aspen T. Reese, Anne A. Madden, Marie Joossens, Guylaine Lacaze, Robert R. Dunn. Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread. mSphere 5, 1 (2020).