San Francisco-Style Sour Bread

Below is my preferred way of making San Francisco sour bread. It does not use a conventional sourdough starter. The two principal souring agents in San Francisco sourdough, lactic acid and acetic acid (vinegar), are added directly to the dough. Proofing time is reduced from 16 hours to 2 hours and you don't have to maintain a sourdough starter. This recipe is the product of many, many test bakes to get the flavor as close as possible to old-school San Francisco sourdough bread.

These directions are for one small loaf or boule. You can make larger loaves simply by scaling the ingredients up.


A digital scale

Lactic acid powder (available through

White vinegar

An eyedropper

Bread flour (found in many supermarkets)

Instant or "rapid rise" yeast. VERY IMPORTANT!!! Do not use "active dry" yeast. Make sure the yeast is "instant" or "rapid rise". If Fleischmann's yeast is used, look for the bright yellow packets.

Water and salt

An electric mixer is helpful but not required.

Some knowledge of artisan baking techniques is helpful.

As you can see, we are dealing with very small quantities. It is thus extremely important to measure the ingredients as precisely as possible. I use an eyedropper to measure the vinegar drop by drop.

Start by making the following "cocktail":

92 grams water

3.5 grams (one half packet) instant dry yeast

1.5 grams white vinegar

Now combine the following dry ingredients in your mixing bowl:

1 cup flour

1/2 teaspoon salt

2.5 grams lactic acid

Disperse the dry ingredients by stirring with a wire whip or fork.

Add the "cocktail" to the dry ingredients and mix until a dough ball forms. DO NOT OVERKNEAD!!!

Place the dough ball on a towel or flax linen cloth and allow to proof for 2 hours.

With a sharp knife or blade, make some slits in the top crust, about 1/4 inch deep. These slits allow the crust to expand while baking.

Bake at 400 degrees F for one hour. You can steam the oven in advance of baking by placing a shallow pan of water in the oven as it heats up, or bake in a cast-iron Dutch oven.

During baking, the slits you have cut into the crust will open up. This is an indication of oven spring, or the degree to which the yeast has raised the bread.

VERY IMPORTANT: It is very important to let the loaf cool completely after baking. This will take some time, anywhere from one-half to one hour or even longer. The flavor is still developing as the bread cools, so for the best flavor it is very important to allow the loaf to cool completely.

GARLIC BREAD: Combine one clove of crushed garlic with 1 stick (1/4 pound) of softened butter or margarine. Cut the bread into slices and spread with garlic butter. Optionally, sprinkle with grated Parmesan cheese. Toast in your still-warm oven at 350 degrees F (this may be done in lieu of allowing the loaf to cool completely), or you may toast the bread under the broiler.

Residents of the San Francisco bay area who prefer to buy rather than bake their own bread can get an acceptable sourdough in several local markets. I have sampled many brands of sourdough from the bay area; Acme sourdough, though significantly milder in flavor than the old-school sourdough bread for which San Francisco is renowned, has the distinctive tanginess that comes from the blend of lactic and acetic acids. None of the other present-day sourdoughs I have sampled in the San Francisco area -- none of them -- comes close to the old-school sourdoughs such as Larraburu, Parisian, Colombo, Toscana, Baroni, Pisano, etc. Acme bread can be found at the following retail locations and possibly more: Piazza's, Draeger's, Whole Foods, Mollie Stone's, Andronico's, Lunardi's, Costco.

Here is the formula in baker's percentages:

Flour: 100%

Water: 63%

Salt: 2%

Instant yeast: 2.4%

Lactic acid powder: 1.75%

White vinegar: 1.0%

Final hydration: 64%

This very technical article is the basis for this recipe. The researchers obtained sourdough samples from the popular Larraburu bakery in San Francisco which closed in 1976. It follows up on research conducted by the USDA in the late 1960's. It identifies lactic acid and acetic acid as the principal souring agents in San Francisco sourdough bread.

Souring agents in San Francisco sourdough bread

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Copyright Chris Clementson