When James W Marshall discovered gold in the hills north of San Francisco in 1848, it sparked a migration of epic proportions. Within a year, tens of thousands of immigrants from both across the country and around the globe had relocated to the Californian city and its surroundings, carrying with them basic necessities like clothing; carpentry tools; and coffee, sugar and flour. However, there was one staple item that would become a part of the city’s history forever: starter for bread.

Baking sourdough is an amazing opportunity for patience and presence

In a place where nourishment was scarce, bread starter (a dough that has fermented using naturally occurring bacteria and yeast) was a prized possession during the California Gold Rush, allowing miners to turn drab flour into loaves that were both nutritious and delicious. Somehow, the bread tasted tangier and more flavourful than it did elsewhere, and thus San Francisco sourdough was born.

More than 170 years later, San Francisco is synonymous with sourdough bread. Patrons line up daily for fresh-from-the-oven loaves at Tartine Bakery in the city’s Mission District; and at The Mill, a whole-grain sourdough bakery and independent coffee shop just west of San Francisco’s famed “Painted Ladies” Victorians. Walk into any local market and you’ll find baskets filled with sourdough baguettes from the Bay Area’s own Acme Bread and Semifreddi’s; or make a stop at Boudin Bakery in the tourist hub of Fisherman’s Wharf, where steaming clam chowder comes served in carved-out loaves of the bakery’s own sourdough bread.

With the advent of “sheltering-in-place”, the artisan bread-making movement is now flourishing in homes worldwide, but it’s in San Francisco where the heart of sourdough bread-baking still resides.

“Sourdough has a very rich history in San Francisco,” said Josey Baker, founder of Josey Baker Bread and co-owner of The Mill, where he bakes and sells his creations. “Though a lot of people have the misunderstanding that it was invented here, or that San Francisco is the only place where you can make it.” Neither of which, Baker says, is true.

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Rumours often swirl about the city’s relentless fog playing a role in the taste of its sourdough, cultivating a type of wild bacteria that only exists in San Francisco. There’s also the fact that it was California miners making their way to north Alaska and Canada for the Klondike Gold Rush, and bringing their sourdough starters with them, who earned the nickname “sourdoughs”, because they would actually cuddle with their starters on cold nights to keep the yeast active. These men became known for their fresh bread and assured their own nourishment in the process.

Then there’s Boudin Bakery, considered San Francisco’s oldest continuously operating business, which has been churning out loaves of sourdough bread since first opening its doors in 1849 – just one year after Marshall discovered gold at Sutter’s Mill. Founder Isidore Boudin, a French immigrant and bakers’ son, obtained the bakery’s original wild yeast starter from a gold miner, and they’ve been using the same mother dough (another name for sourdough starter) for more than 170 years. An interesting tidbit: it was actually Louise Boudin, wife of the then-late Isidore, who saved Boudin’s mother dough from destruction during San Francisco’s legendary 1906 earthquake.

Another link between San Francisco and sourdough bread: the region’s long-running, ingredients-focused ethos. “Here in the Bay Area we have a really high level of interest in the valuing of food,” said Baker, “and sourdough is both healthier and more labour-intensive than your average loaf. I own a whole-grain sourdough bread bakery. It’s not lost on me that if I try and open up something similar in most other parts of the country, it just wouldn’t work.”

But despite all the connections and stories, sourdough isn’t endemic to San Francisco. Actually, it’s one of the oldest bread types – a fermented and leavened dough that dates back at least 4,500 years to ancient Egypt. What makes sourdough unique is the symbiotic relationship between its wild yeasts and various bacteria species such as lactobacilli that occur naturally when left alone, though according to Baker, there are various opinions on how the bread truly originated. One plausible tale, he said, is that someone had prepared a porridge with coarsely ground grains, and then left it alone for a few days. “During that time, it started bubbling and smelling sort of funny,” said Baker. “It likely sat in the sun, and eventually baked up into something that was both more delicious and more nourishing than its unfermented predecessor.”

In the 1970s, researchers Frank Sugihara and Leo Kline set out to discover just what kind of lactic acid microbe – similar to the ones found in yogurt or kimchi – was providing San Francisco sourdough with its characteristic taste. They happened upon a then-uncatalogued bacterium, so they gave it a name: lactobacillus sanfranciscensis, after San Francisco, still believing it was Bay Area-unique. However, l. sanfranciscensis has since been discovered in approximately 90 other countries, thriving in growing conditions that include a pH range of 3.9 to 6.7 and fermentation temperatures between 20°C and 27°C.

Still, regardless of where it’s produced, Baker stresses that what really makes a good sourdough bread is this taste. “San Francisco sourdough as a bread style has a characteristically tangy flavour profile,” he said, “which is really due to the acetic acid (another acid that forms during fermentation).” Yet its flavour profile has more recently shifted to something much milder, with many bakers (Baker included) balancing the bread’s lactic acid sourness with the nuance and characteristics of the grains that are employed in that particular loaf.

“Rather than flavouring from fermentation,” said Baker, “the dominant force at work here is the grains from which each loaf of bread is made. Less of the acetic acid (think vinegar), and more of a sweet lactic acid-forward fermentation (think yogurt).”

Another sourdough perk? It’s good for you. The natural bacteria and yeasts in the sourdough starter make for a healthier gut, and help pre-digest some of the flour – providing a break for our own digestive systems. Sourdough also keeps better because of the natural preservatives formed by the sourdough culture’s organisms. “Flavour, digestibility, keeping qualities,” said Baker. “In my eyes, it’s all pretty appealing.”

Baker got his start in the kitchen of a Mission District apartment just more than a decade ago, obtaining a starter from a friend that he still uses today. “It was this weird-looking little lump,” he said, “originating with flour and water – nothing else.”

One thing he quickly learned: sourdough is not fool proof, like a yeasted bread. It takes time and nurturing. You begin with a starter, which Baker said you can make on your own with a combination of flour and water, or obtain one instead. Many home bread-makers and local bakeries will offer a bit of their starter upon request, including The Mill. “We’ve always done a barter,” said Baker, “though it used to be that people had to give us a poem of their own creation. Lately we’ve opened it up so that you trade whatever you like. Some people give us a six-pack of beer, others ice cream… A customer recently traded us a jar of 100 handmade paper cranes.”

He also suggested steering clear of dried-out starters that are mass produced, which do nothing for the bread’s flavour or nutritional value. “[With a starter] what you’re doing is coaxing the wild yeast and bacteria that’s already present on the grain,” Baker said, “into a population that’s conducive to getting the characteristics in the finished loaf of bread that you want.”

To do this, he said, you basically mix a quarter of a cup of flour and water (35g flour and 60g water) together and you let it sit for a day. Then you throw out all of it apart from a little bit, and you do it again. “Repeat this for two weeks and it’ll most likely result in a healthy and active sourdough starter,” said Baker, meaning it’s creating lots of bubbles and floats easily in a glass of water

Still, “most likely” refers to the fact that not all flour is created equal. “If you’re working with bleached, conventional white flour that’s been sitting in a warehouse for two years,” Baker said, “you’re much less likely to produce a healthy, active starter than, say, whole grain, which has a lot more good stuff in it that not only our bodies, but also the microorganisms, really like.” For his own purposes, Baker especially likes whole grain rye flour, available at speciality markets such as Whole Foods in the US.

Once you have your starter, you can begin making your bread – a process that Baker says generally takes one to two days. “All you really need is a thermometer, a bowl and either a [baking] stone or Dutch oven for baking,” he said. “Although a stand mixer is handy for folding the dough, it’s not necessary. I actually recommend doing it all by hand, to get a feel for the process.”

It’s this overall process, said Baker, that is the ultimate key to sourdough bread-baking. “In these days of Instagram and Facebook it’s easy to see the glory shots from everyone’s successes,” he said, “but the reality is that there are a lot of failures that happen outside of that little window. Baking sourdough is an amazing opportunity for patience and presence, and then you get to share it with someone.”

***

Josey Baker sourdough bread recipe
(makes 2 loaves)

Step 1 – Sourdough starter

For this recipe, you’ll need a sourdough starter, which is a small amount of fermented dough made with natural bacteria and yeast. If you can’t get one from your local bakery or a friend, you can make one by combining 35g flour and 60g water together and letting the mixture sit out on the counter (covered) for at least a day.

To begin your sourdough bread dough, you need to first feed and activate your starter:

• If at room temperature, mix 10g starter, 100g lukewarm water (about 29°C) and 100g rye flour in a small container, and repeat every day until ready to use (for at least two weeks if making your own starter from scratch).

• If in the fridge, mix 10g starter, 90g lukewarm water (about 29°C) and 100g rye flour, and feed once every week; then two to three days before making your preferment (see next step), take out of the fridge and keep at room temperature, feeding daily until ready to use.

Note: With each feeding, you can either discard the unused portion of starter or use it for another purpose.

The starter is ready to use around 12-24 hours after the last feeding. When your starter is ready, it should smell yogurty and pleasantly sour, have a good amount of bubbles, and pass “the float test” by dropping a tablespoon of starter in water: if it floats, it’s ready.

Step 2 – Preferment

Mix together 20g active starter, 90g whole wheat flour and 90g lukewarm water. Be sure to do this 12-24 hours before you plan to mix your dough (see next step). By that time, it should be nice and bubbly and look like thick pancake batter. And again, use the float test to make sure it’s ready.

You can control your preferment’s pace by controlling the temperature of the water and where you place the mixture in your home; try to keep the mixture between 24-29°C.

Step 3 – Mixing the dough

200g active starter
500g wholegrain wheat flour
500g bread flour
800g warm water (29°C)
20g sea salt

Mix together everything except the salt and about 100g of the water until no dry spots remain. Let the dough rest for 20 minutes. Control the fermentation speed by again controlling the temperatures of the water and dough; keep dough ideally around 26-28°C.

Add the remaining water and salt, and mix. Let dough rest for another 30 minutes.

Keeping dough in the bowl, stretch and fold it upwards while rotating the bowl to give it strength and redistribute the yeast and warmth. When it starts to tear, it’s ready to rest. Repeat two more times at 30- to 45-minute intervals. Let it rest for another 20 minutes before shaping the loaves (see next step).

Step 4 – Shaping the loaves

When your dough is nice and billowy (about 1.5x the volume), it’s ready for shaping.

Lightly flour your surface and gently drop out your dough. Divide in half (to make two loaves).

Fold up the bottom of each piece of dough 2/3rds the way, and then stretch the top and fold down 2/3rds, like a three-fold letter going into an envelope.

Rotate the one of the pieces of dough 90° so the seam is vertical; if the seam is too far to one side, just shimmy it back towards the middle. Roll the dough from the top towards you and end when the seam faces you, then seal it on all sides by using the palm of your hand to press together the seam. Repeat with other piece of dough.

Dust dough lightly with flour, then use a bench scraper to pick up one piece of dough (keeping all the tension in the dough), and place it seam-side up inside a lightly floured basket or bowl to rest. Repeat with other piece of dough.

Leave the loaves out on the counter at room temperature (uncovered) for 2-3 hours, or in the fridge for 10-20 hours, until the they have risen by about 1.5x.

Step 5 – Baking

Heat oven to 245°C; also preheat your cast iron Dutch oven or baking stone.

Gently drop your dough out of its basket onto parchment paper or a cutting board. Carefully score the top of the dough with a lame (or sharp knife or scissors) and place it into your Dutch oven or onto your baking stone with the seam facing down. Cover immediately to keep steam in (if using a baking stone, you can cover with a metal bowl). Repeat with second loaf.

Note: If you don’t have a Dutch oven or baking stone, you can bake your bread in an oiled loaf pan; just be sure to cover it with foil, leaving a tented space for the dough to rise while baking.

Bake loaves for 20 minutes and then uncover (carefully as the steam will be hot!). Bake for another 30-40 minutes or until bread registers 88-96°C.

Let bread rest for at least 30 minutes to finish baking internally and cool down. Then have a feast and share the bread with someone you love.

***

Culinary Roots is a series from BBC Travel connecting to the rare and local foods woven into a place’s heritage.

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