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S.F. Sourdough Yeast and Lactobacillus

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chris319's picture
chris319

S.F. Sourdough Yeast and Lactobacillus

I put this out for anyone who might be interested. It describes how to make L. sanfranciscensis and C. humilis, the lactobacillus and yeast in S.F. sourdough. It comes from US patent #3734743 by Kline and Sugihara. I have updated the names of the microorganisms from the patent to reflect the current names.

Is thre anyone with a knowledge of chemistry who could say how feasible this would be to do given a properly-equipped laboratory? Note that these both utilize baker's yeast.

EXAMPLE 4

Preparation of pure cultures of the sour dough bacteria L. sanfranciscensis

 The bacteria in question grows well on a broth containing the following ingredients:

Sour dough bacteria (SDB) broth

Percent

Maltose __________________________________ __ 2

Commercial yeast extract ____________________ __ 0.3

Fresh yeast extractives (FYE)* __________ __ 0.5 to 1.5

'Sorbitan polyoxyethylene monooleate (Tween 80) .. 0.03

Casein hydrolysate (Trypticase) ____________ __ 0.06

Water ____________________________ __ To make 100

 

*Prepared by autoclaving a 20% suspension of commercial compressed baker's yeast in distilled water for 30 minutes at 15 p.s.i., allowing the suspension to settle overnight at 34—35° R, decanting and further clarifying the supernatant by centrifugation. The extract prepared in this manner contained 1.5% solids and if not to be used within a few days, was frozen or freeze-dried immediately. The FYE preparations are used in a proportion to furnish 0.5 to 1.5% of the dry FYE solids.

 Adust to pH 5.6 with 20% lactic acid or acetic acid or1 to 6 N HCl.

 The broth is sterilized by autoclaving it, cooled, and inoculated with about 1% of a broth culture of the bacteria, then incubated at about 80° F. for 1 or 2 days.

Since growth of the bacteria is stimulated by CO2, it ispreferably to carry out the culture in an atmosphere containing some CO2. This may be done by ?ushing air out of the top of the culture vessel with CO2 and then stoppering the vessel. Alternatively, the vessel can be placed within a receptacle containing about 25 to 95 volume percent of CO5, (the remainder, air). Alternatively, one may sparge the culture with such gas mixture. During the culture the system is preferably agitated or shaken slowly to get good contact between the growing cells and the nutrients. The bacterial cells are harvested by centrifuging the broth culture, preferably using a refrigerated centrifuge.

The centrifuge cake is then washed with chilled 1% aqueous salt solution to remove nutrients, metabolic products, etc. The washed cells can then be used as the bacterial inoculum for liquid starter make-up.

 

If the cells are not needed a short time after preparation, they may be preserved as follows:

The washed cells (100‘ parts) are suspended in 200 parts of a stabilizing carrier (a mixture of glycerol and sterile SDB broth) and the suspension is ?ash frozen, using liquid N2 or Dry Ice-acetone slush. The culture is then held in a frozen state (about -20° F. or below),

whereby it retains its viability for at least 2 months. When the product is to be used, it is thawed and used directly.

 Further details on preparation of cultures of L. sanfranciscensis are disclosed in our copending application referred to above. Methods whereby this species may be isolated from source materials such as sour dough sponges are also disclosed in said application.

Cultures of several strains of Lactobacillus sanfranciscensis useful for the purpose of the invention have been deposited in the Stock Culture Collection of the US. Department of Agriculture, Northern Regional Research Laboratory, Peoria, Ill.61604, from which organization samples of these strains may be obtained.

 

EXAMPLE 5

Preparation of pure culture of the sour dough yeast Candida Humilis.

The yeast in question grows well on many media, including those used for growing commercial baker’s yeast. We have routinely cultured the organism on the following broth:

                                                                                     Percent

Glucose ____________________________________ _. 2

Yeast extract _______________________________ __ 0.5

Casein hydrolysate (Trypticase) _________________ __ 1

Water ________________________________ To make 100

 

The broth is sterilized by autoclaving it, cooled, and inoculated with about 1% of a broth culture of the yeast, then incubated at about 86° F. for 1 or 2 days under highly aerobic conditions. The yeast cells are harvested by centrifugation or filtration, then washed with chilled 1% aqueous salt solution to remove nutrients, metabolic products, etc. The washed cells can be used directly or stored in the refrigerator for future use. For longer storage, the yeast can be dried — this is preferably done by extruding it through a die to form noodle-like filaments which are dried to a moisture content of about 8% in a current of air at about 100-140°F. To prevent loss of viability, the temperature of the air during the last part of the drying cycle is kept in the lower portion of the stated range, or, alternatively, the humidity of the air stream is increased while keeping the temperature high.

Cultures of several strains of candida humilis useful for the purpose of the invention have been deposited in the Stock Culture Collection of the US. Department of Agriculture, Northern Regional Research Laboratory, Peoria, 111. 61604, from which organization samples of the strains may be obtained. The strains are designated as Nos. NRRL Y-7244, Y-7245, Y-7246, Y-7247, and Y

7248. As noted above, in the sporulating form the yeast may be termed Saccharomyces exiguus.

suave's picture
suave

It describes how to grow, not how to "make" them.  You'd still need a pure culture.

chris319's picture
chris319

It describes how to grow, not how to "make" them.  You'd still need a pure culture.

Yes, I see that now.

There are four strains of the yeast, candida humilis, in the on-line catalog of the USDA culture collection. Each strain has a single-letter identifier. I am going to work under the assumption that this letter corresponds to the bakery from which they were obtained.

Y-7244 - strain B (Baroni bakery)

Y-7245 - strain C (Colombo bakery)

Y-7246 - strain L (Larraburu bakery)

Y-7248 - strain T (Toscano bakery)

L.A. Times food writer Marion Cunningham spoke to Leo Kline in 1992 and the bakeries were identified: http://articles.latimes.com/1992-09-24/food/fo-1049_1_san-francisco-home

The USDA has the culture for lactobacillus sanfranciscensis but it does not appear in the on-line catalog. The identification number is NRRL B-3932. In my correspondence with the curator of the collection, no mention was made of multiple strains.

In patent #3734743, example 2 describes how to make starter from the pure cultures:

EXAMPLE 2
Using pure cultures
Parts
Flour _ ____ _____ .._ 100
Water ____ 250
Pure cultures (see below).
Salt ______________________________________ __ 2
Adjust pH to 5 with acetic acid (optional).

The pure cultures used are those of Candida humilis and of Lactobacillus sanfranciscensis. Enough of the culture is provided to furnish approximately the following concentrations of these organisms in the liquid starter:
T. holmii: About 2X106 cells/ g.
L. sanfranciscensis: About 1X108 cells/ g.

Note that the names have changed since the patent was filed.

So authentic S.F. sourdough has not been lost to the ages.

dabrownman's picture
dabrownman

to make your own SD starter from scratch.  I  know you have had problems doing so,.but I have made every SD culture listed in Clayton's book, used D. Winks and J.Ortiz method several times, done several YW's,  started some from just WW or Rye a little milk and some water,  Never had one that didn't  do well - it just isnlt that hard t do.  Some just take longer than others with J Ortiz being the fastest.  I think Debra Wink's method using OJ, pineapple or tangelo is pretty fool proof. 

To be honest i don't even think about making a starter or worry about it at all.   Just grind up some fresh gains, squeeze some fresh orange juice to lower the ph, use tap water that has sat out uncovered for 24 hours and follow the directions - no worries.  Next thing you know in a couple of weeks you will have a starter,

chris319's picture
chris319

Tell me how easy it is to make your own starter.

I felt this information would be of interest to those of us who grew up with this bread and to the many people who have expressed an interest in Larraburu, that this bread has not gone totally extinct.

Even easier would be to order Ed Wood's San Francisco starter mix.

dabrownman's picture
dabrownman

if you don't live in SF pretty near the location of the old bakery any starter will take on the characteristics of where you live in very short order..  When I started my first SD starter in SF in 1973 it was very different that the same one I moved all over the world.  Where ever it was it was different, sometimes more sour sometimes not and the local flour I fed it effected it too.  Since I have been in Phoenix the past several years it has been pretty much the same and only the flour feed and now stiff cold storage has changed it.

So it is way cheaper and easier to start your own SD starter and let it be what it is going to be anyway,  

chris319's picture
chris319

I've been reading posts from people saying that, being outside S.F., their purchased S.F. starter changes flavor over time. Pioneer bakery used to be in Venice, CA and until recently made a sourdough which compared very favorably to S.F. breads in flavor, so maybe you have to be near the Pacific. 1973 was the year I first moved to S.F. and in those days you just went to Safeway or Cala Foods and bought a loaf of Larraburu.

It occurs to me that if the flavor in sourdough comes from the LABs, just use the USDA yeast culture in making your own starter and the LABs would be home-grown. That might be useful for the starter-challenged like me, rather than using baker's yeast.