Sourdough Cultures
By Master Rowan of Windtree Tower, O.L.
“Bread... is an ingenious
technology for improving
the flavor, digestibility, and
nutritional value of grass.”
Introduction
Sourdough Cultures
Equipment
Capturing a Sourdough Culture
Starting a Dried Culture
Managing a Sourdough Culture
Preserving Sourdough Cultures
Baking with Sourdough Cultures
Bibliography
Web Resources
Article- Microorganisms of the San Fransisco
Sour Dough Bread Process.
Sourdough baking is making wheat bread with
a sourdough culture rather than using baker’s yeast.
A sourdough culture is a mixture of wheat flour
and water that supports an acid-tolerant yeast and a
lactobacillus bacteria. Prior to the late 1800’s, all leavened bread was baked with sourdough cultures.
Baking with sourdough cultures is very different than baking with baker’s yeast. Baker’s yeast is a
monoculture, or is made up of all the same organisms. It rises quickly and predictably and behaves
more like a chemical additive than a living thing. A
sourdough culture is a symbiotic relationship between at least one ‘wild’ yeast and one lactobacillus
bacteria.
Bread made from sourdough cultures have a
more complex flavor and can range from very sour to
very mild in taste depending on baking techniques.
Sourdough bread also is slower to rise. Pollan says
that the bacteria produces an antibiotic compound
and inhibits other bacteria and extends the shelf life
of the finished bread.
Sourdough Cultures
Equipment
-Michael Pollan, Cooked
Contents
A sourdough culture is a mixture of wheat flour
and water that supports an acid-tolerant yeast, Candida milleri which is sometimes called Saccharomyces
exiguous, and a lactobacillus bacteria, Lactobacillus
sanfranciscensis. The name for the bacteria came
from the faulty conclusion that the species was
unique to San Francisco. The acidic environment provided by the lactobacilli helps prevent contamination
of the culture by other organisms. The wild yeasts in
the culture can withstand a more acidic environment
that baker’s yeast. A sourdough culture will last a
lifetime with appropriate care.
Sourdough cultures can be captured from nearly
any location or started from other cultures, wet or
dried, shared or purchased. Management of these
cultures is done by ‘feeding’ them, which is adding
more of the flour and water media, and incubating
them at room temperature or slightly warmer. Cultures may be preserved through refrigeration, freezing, drying, or a combination of these methods.
Most of the equipment needed for working with
sourdough can be found in any kitchen, but here are
few notes and suggestions.
Glass jars- These are required for working with
sourdough because they are easy to clean and they
are transparent. One quart canning jars are ideal, but
any glass jar will work.
Proofing box- While not actually required,
proofing boxes are wonderful tools for any bread
baker. They are essentially a incubation chamber
where a desired temperature can be maintained.
Inexpensive ones can be assembled with Styrofoam
coolers and various heating elements including
light bulbs and plant warming mats. Woods’ Classic
Sourdoughs... has complete plans for one or Google
“how to make a bread proofing box” and you can
find many different plans and directions. I bought
an electronic, collapsible one from Brod and Taylor,
http://brodandtaylor.com, and while it was pricey, I
really like it.
Capturing a Sourdough Culture
As described by Wood in Classic Sourdoughs...
Directions
1. Mix 2 cups (280 g) of flour and 1 1/2 cup warm water in a 2 quart (2 liter) bowl.
2. Stir the mixture with sufficient vigor to beat in additional air.
3. Expose the bowl and its contents to the air, preferably outside. Bowl may be covered with fine mesh or
cheese cloth.
4. Stir the mixture vigorously at least twice every 24
hours.
5. In two or three days, some bubbles should appear on
the surface as the first indication of success.
6. At this point, feed it an addition cup of flour and
enough water to maintain consistency .
7. You may need to repeat additional feedings at twelve
to 24 hours for several successive days.
8. When you capture yeast that is active enough to be
useful, it will form a layer of foam 1 to 2 inches (2.5
to 5 cm) deep.
9. If it doesn’t attain this level of activity in four to five
days, you probably should abandon the attempt and
try again in a different location.
10.Once you have a good bubbly culture, transfer it to
one quart jar and maintain as a normal culture.
Rowan’s Notes
Making More Sourdough Culture
I have found once I got involved with sourdough
cultures I found myself making LOTS of it. So if you’ve
got a little bit of active culture and you want more...
Read the “Managing a Sourdough Culture” and
keep repeating those steps. A half cup of culture becomes a half a jar, half a jar becomes two half jars, and
so on.
Just remember to only fill whatever container you
use half full of just fed culture or it will grow through
the lid and make an awful mess. Trust me, I know this
from experience.
Once you have an active culture be sure to preserve
some. Take a jar, label it and put it in the refrigerator, or
give it to a friend to put in their refrigerator for safekeeping, or dry some of it, bag it, and freeze it.
Starting a Dried Culture
Dissolve 1 teaspoon of dried culture in ½ cup
of warm water, 1050F. Directions that come with
commercial cultures often urge you to use the entire
package, but this is not necessary. Reseal the original package, place it in a Ziploc bag and refrigerate.
Add enough flour to make a thick, pancake batter consistency, place in glass jar, label, cover, and
incubate at 850F.
In 8-12 hours you should see signs of activity.
Once the culture is active use it to inoculate
greater amounts of flour media to produce as much
culture as desired. Just ‘feed’ it as described in
“Managing a Sourdough Culture”.
Preserving Cultures
If you are not going to be baking bread for a
while and wish to preserve the culture, there are
several ways to preserve it. Some authors urge moving cultures to only white flours for storage as the
oils and other nutrients in whole grains can spoil or
become rancid over long periods of time.
The easiest way to preserve a culture is to take
a jar of it when it is most active after a feeding and
simply put it in the refrigerator. Cultures can go
up to three months between feedings this way. The
flour media may separate with a clear liquid on the
top, which is normal and should be mixed into the
rest of the culture when reviving it. To revive the
culture, take a tablespoon or two of the old culture,
mix it with a cup of warm water, add enough flour
to make a thick pancake batter consistency, put it in
a jar, cover, and incubate. Bubbles and rising of the
culture should appear in 8-12 hours.
Another way to preserve a culture is to dry and
freeze it. Take a jelly roll tray or other tray with a
raised edge, line it with parchment paper, and pour
a jar of active culture onto it and let dry. It will
take 2-3 days to dry, and then it may be crumbled,
put into Ziploc bags and be frozen. Frozen, dried
cultures will last for months and can be revived like
any dried culture.
Sourdough Research
A 1970 article in Applied Microbiology details
some wonderful research on sourdough yeast. A
copy of it is attached to the back of this paper.
Managing a Sourdough Culture
Keeping an active culture going requires feeding it every day or two when it is kept at room temperature.
The amounts given can be changed but when done the fed culture should look like thick pancake batter. Active
cultures have cycles of great activity directly after feeding and then dying back down after a few hours as seen in
the chart below.
Directions
1. In 1 cup of warm water, 1050F, add at least a tablespoon, but preferably the whole jar of existing active
culture. Stir thoroughly.
2. Mix enough flour to make a thick pancake batter consistency. Pour into 2 glass jars, filling no more
than half full to allow for expansion. If desired, use a Sharpie marker to draw a line on the jar to show
the starting level of the fed culture and write the date. When the jars are washed these marks are easily
removed with rubbing alcohol.
3. Incubate in proofing box or at room temperature at 850 F.
4. Repeat every day or two as long as the culture is kept active.
It is good to note that eventually some of the culture will have to be discarded as it continues to acidify, often
to the point where it becomes so acidic that the yeast can’t survive. As you become more familiar with sourdough and what is required for baking, this waste can be minimized.
Sequence of Sourdough Growth and Dormancy
Activity Level
Peak of
bacterial
metabolism
Early Growth
Peak of yeast
leavening
activity
Dormancy
Time
From Wild Bread by Lisa Rayner
Baking with Sourdough
Baking with sourdough cultures is not unlike baking with baker’s yeast, differing mainly in longer rising
times and controlling the acidity of the bread.
Wood describes 3 “proofs” or risings in his sourdough baking technique. The first one is the “culture proof”
where the culture is fed and made active. Then he has a “dough proof” after the active culture is made into
dough, kneaded, and then allowed to rise. Finally there is the “loaf proof” after the dough is rested, then shaped
into a final form and allowed to double in bulk in or on the pan, basket, or metal sheet before it is baked.
The “sourness” of sourdough bread is easily controlled. Longer, up to 12 hours or longer, fermentations are
required to really develop the sourdough taste. Milder-tasting breads are produced with shorter fermentations.
Some authors say that by lowering the temperature of the fermentation the yeast in the culture can be induced to grow faster to produce a better rise and less acidity. Conversely a warmer fermentation will favor the
bacteria and yield a stronger flavor but inhibit rising.
Bibliography
Note- this list includes books on sourdough, general bread baking, and volumes of interest to the SCA baker.
Pollan, Michael; Cooked: A Natural History of Transformation; © 2013; Penguin Press, New York; ISBN: 9781594204210 (Pollan’s book is a must have for any cook. The
section on bread baking alone is worth the price, but also
includes sections on grilling, cooking in pots, and fermentation.)
Rayner, Lisa; Wild Bread: Hand-Baked Sourdough
Artisan Breads In Your Own Kitchen; © 2009; Lifeweaver
LLC, Arizona; email: [email protected]; Web: www.
LisaRayner.com; ISBN 978-0-09800608-1-2 (This selfmade and self-published little volume is packed with information for sourdough bakers. Covers the topic more completely than any other book I’ve seen.)
Reinhard, Peter; The Bread Baker’s Apprentice: Mastering The Art Of Extraordinary Bread; © 2001; Ten Speed
Press, Berkley, California, Web: www.tenspeed.com; ISBN:
978-15008-268-6 (If you want to learn serious bread baking, get this book and the volume below. Incredible works.)
Reinhard, Peter; Crust And Crumb: Master Formulas
For Serious Bread Bakers; © 1998, 2006; Ten Speed Press,
Berkley, California, Web: www.tenspeed.com; ISBN: 9781-58008-802-2
Web Resources
• Sourdoughs International, Ed Wood’s sitehttp://www.sourdo.com/
• Sourdough Companion:
https://www.facebook.com/SourdoCompanion
• Northwest Sourdough:
http://www.northwestsourdough.com/discover/
Robertson, Chad; Tartine Bread; © 2010;
Chronicle Books, LLC, San Fransisco, California,
Web: www.chroniclebooks.com, ISBN: 978-0-81187041-2 (A beautiful book with perhaps more pictures
than hard information, but it describes how to make
the “artisan” loaf)
Rubel, William; Bread: A Global History; ©
2011; Reaktion Books, London, Web: www.reaktionbooks.co.uk; ISBN 978 1 86189 854 8
Wing, Daniel and Scott, David, The Bread
Builders: Hearth Loaves And Masonry Ovens; ©
1999; Chelsea Green Publishing Company, White
River Junction, VT, Web: www.chelseagreen.com;
ISBN: 1-890132-05-5 (Another great book on baking
‘artisan’ breads. It covers everything from baking to
building bread ovens.)
Wood, Ed and Wood, Jean; Classic Sourdoughs,
Revised: A Home Baker’s Handbook; © 1989, 1996,
2001, 2011; Ten Speed Press, Berkley, California;
Web: www.tenspeed.com, ISBN: 978-1607740070
(The first part of this book is on cultures and the
Woods’ world-wide search to find them, the rest is
recipes.)
About the Author
I’ve been baking bread since I was a child, but
haven’t really explored sourdough baking until the
last year or so.
I’m always interested in hearing what other
SCA bakers are doing and I can be reached at my
email address- [email protected]