San Francisco-Style Sour Bread
I am a San Francisco sourdough snob. I grew up on the San Francisco peninsula when the gold-rush-era sourdough bakeries for which San Francisco was renowned were still going strong. Our family was particularly partial to a brand called Larraburu — it was a staple at family gatherings — that is, until the bakery closed in May, 1976 due to financial problems. After Larraburu closed, the competing bakeries were taken over by corporate interests which, in the name of efficiency, cut corners in the manufacturing process. They continued to bake for several years and are no longer in operation.
I now live in the Los Angeles area. A supermarket near me (Gelson's) carries a house brand of sourdough. One day I picked up a loaf in the store and sniffed it, thinking "This can't be any good." Much to my surprise, I liked what I smelled. I took a loaf home and sampled some.
It was not exactly the sourdough I remembered from my bay area days but it had a lot going for it. I examined the ingredients and saw that they did two things right: they added lactic acid and a powdered form of acetic acid. No wonder I liked this bread! Lactic and acetic acids are the main souring agents in gold-rush-era sourdough. These two acids gave the bread a very authentic flavor.
San Francisco sourdough bread has been much studied the world over. In the late 1960's the USDA studied sourdough samples obtained from five San Francisco-area sourdough bakeries. The acid content of the bread was studied again several years later and the results published. The two souring agents — lactic acid and acetic acid — are now well known.
I had been working on replicating San Francisco sourdough in my own kitchen which is hundreds of miles from San Francisco, with gooey starters and hours and hours of proofing time. I had a good deal of success capturing the flavor of the bread. Inspired by the sourdough I found in the supermarket, I asked myself, "If lactic and acetic acid (vinegar) are what give the bread its unique tangy flavor, could I make an authentic-tasting replica of San Francisco sourdough simply by adding the acids to the dough of conventional yeasted bread?".
It is "cheating", yes, but I have no problem with it. The microorganisms in a sourdough starter produce lactic and acetic acid, so you're adding acids which would be present anyway in naturally-fermented sourdough. As they are the two main acids found in fermented sourdough cultures and are mainly responsible for its tangy flavor, those are the only acids I use. I refrain from using fumaric, malic, ascorbic and citric acids typically used in the manufacture of sour foods as they are not present in significant quantities in old-school San Francisco sourdough cultures.
It took many, many test bakes to get the flavor just as I remembered it from the 1960's and 1970's. It is basically a yeasted bread with the acids added.
There is one absolutely INVIOLABLE rule: you MUST use "instant" or "rapid rise" yeast. Active dry yeast will give it an awful yeasty aftertaste, so "instant" or "rapid rise" yeast is a MUST!!!
I make it to 64% hydration with the vinegar taken into account, but this is not inviolable. I add the lactic acid powder and salt to the flour and mix them together with a fork or whip. I also make a cocktail of water, yeast and white vinegar. Another inviolable rule is that the ingredients be measured as precisely as possible.
I have only made this with white wheat flour, either bread flour or all-purpose. Making it with whole wheat, rye or some other flour would change the flavor and it would no longer be authentic. As there is no live culture, there is no contention between the yeast and a lactobacillus for maltose. It is important to emphasize that we aren't adding any ingredients which wouldn't be found in a live S.F. sourdough culture.
Here is the formula in baker's percentages:
Diastatic malt powder: 2%
Warm water: 63%
Instant yeast: 2.4%
Druid's Grove lactic acid powder: 0.8 %
White vinegar: 1.0%
Final hydration: 64%
Here it is in grams as I make it:
Flour: 146 g
Diastatic malt powder: 1/2 tsp.
Warm water: 92 g
Salt: 3 g (1/2 tsp)
Instant yeast: 3.5 g (1/2 packet)
Druids Grove lactic acid powder: 1.2 g
White vinegar: 1.5 g (I find it helpful to use an eyedropper)
The dough is allowed to proof for 2 hours on a linen couche or towel. One advantage of this recipe is that the proofing time is dramatically reduced. It can be made in less than 4 hours from start to finish: 1/2 hour for prep, 2 hours to proof, 1 hour to bake and 1/2 hour to cool.
It is also very important to maintain the ratio of vinegar to lactic acid powder as we're empirically replicating the balance of acids found in a real sourdough culture. More of either acid than specified in the formula will result in a peculiar-tasting bread.
Sourdough bread is still available in San Francisco but it is a mere shadow of the breads produced by the legacy bakeries that traced their origins to the California gold rush of 1849, brands such as Larraburu, Parisian, Toscana, Colombo and Baroni (Toscana and Colombo were actually baked in Oakland). Of the modern-day breads I have sampled, one brand, Acme sourdough, comes close to the old-school breads but is significantly milder in flavor. Boudin is sold to tourists on Fisherman's Wharf and in my opinion is markedly inferior to the other old-school breads. It has a distinct vinegary flavor which was not present in the other breads.
Mythology has it that true San Francisco sourdough could only be made in the geographic vicinity of San Francisco due to the magic imparted by San Francisco's fog, its air, its climate, its local yeast, etc. We now know that the microorganisms found in San Francisco sourdough cultures can be found the world over. Some modern-day San Francisco bakers produce delicious breads, but these breads could be from any city in the U.S. There is nothing uniquely or distinctively "San Francisco" about them. None of San Francisco's sourdough legacy lives in them. The techniques presented here, though unorthodox, produce a bread which authentically replicates the flavor of traditional San Francisco sourdough, to be used as a guidepost in keeping the legacy alive.
I must give special thanks and kudos to doc.dough for posting the documentation of the San Francisco sourdough process here several years ago. In addition, here is a paper in which the acidic composition of S.F. sourdough was studied:
Lactic acid powder: