Baking bread without commercial yeast

Refr Fiachson – Culinary Symposium 2011

Commercial yeast as we know it today was not readily available until the late 19th or early 20th centuries (Wood 19).  Written sources dating back to the ancient Egyptians document leavened bread, so how did they do it?


Until the 19th century, all bread was what we modernly refer to as “sourdough”, meaning that was fermented with “wild” yeast and lactobacilli.  That does not necessary mean that all bread was sour.  Many “sourdough” cultures produce bread that is not particularly sour, and even with cultures that can produce very sour bread, the shorter the fermentation period the less sour the finished product will be.  Bread made during a single day, using typical sourdough starters, will produce a loaf that is not noticeably sour.  An overnight fermentation will give a slightly more pronounced sour flavor, but a truly “sour” loaf may take 2-3 days to mature, particularly in mild weather.

One of the largest differences between sourdough cultures and commercial yeast is variability.  Commercial baking yeast consists of only one species worldwide.  Sourdough cultures are often composed of more than one strain of yeast, and those strains differ depending on where in the world the bread is made (Wood 20).  That means that the sourdough culture being used in San Francisco is intrinsically different from that in Helsinki or Cairo.  Some cultures produce a much sourer flavor that others, and different cultures are adapted to different flours and growing conditions.  Cultures adapted to rye will not work as well with wheat, etc.


Not all grains are created equal.  More specifically, not all grains contain the same kind of proteins.  The way that yeast creates leavened bread is by generating carbon dioxide gas.  For bread to rise, that gas has to be trapped inside the bread.   In wheat bread, those gas bubbles are trapped inside webs of gluten, which is a protein that forms sticky webs that can retain gas bubbles.  Rye contains a different protein that also forms webs (differently) to retain gas bubbles.  Even among species of wheat, different levels of gluten produce bread that rises differently.  Spelt, emmer, kamut, and other “old” varieties of wheat do not have as much gluten and will not rise as well.  Grains like barley, millet, rice and oats do not contain enough gluten to produce bread that will rise.  That does not necessarily imply that dough made from those grains cannot  be fermented, just that they will not rise in the way that wheat or rye breads will.

Wheat grows well around the Mediterranean, and in the Near and Middle East, but outside that range it becomes harder to grow.  The farther North you travel, the less wheat is likely to be grown.  In Viking Age Scandinavia, for example, wheat was a comparative rarity, and most examples of bread that we have from the archeological record are composed mainly of barley, oats, and rye, with only small amounts of wheat (Hansson).


Grains all contain starch of one form or another.  Starch by itself is mostly tasteless to humans.  There are several ways of breaking down the starch in grains into less complex molecules that we can taste.  Once grain is ground into flour, and water is added to the flour, enzymes in the grain go to work on the starches and break them down into their constituent sugars and other shorter molecules.  The longer those enzymes are allowed to work on flour, the more starch will be broken down and the more flavor the bread will have.  That is why grocery store French bread is nearly flavorless, and the same ingredients made into “artisanal” French bread taste so much more complex (Reinhart 39-40).  Starches can also be broken down by heating flour in water, as in gravy.  In terms of bread, this usually involves “mashing” the grain by heating flour and water and allowing the heat to break down the starch molecules.


The two main reasons commercial yeast has largely replaced sourdough in baking are that it takes longer, and that it is less predictable.  Wild yeast tend to produce gas more slowly than commercial yeast, which means it takes longer for sourdough bread to rise.  Also, the souring/fermentation process takes longer to develop the kinds of textures and flavors for which real sourdough breads are famous, because the enzymes present in the dough have more of an opportunity to break down the starches and produce more flavorful dough.  This also applies to grains that will not rise, such as barley or oats.  Fermenting dough made from such grains makes bread that is much more flavorful, if flat.

Acquiring a Sourdough Culture

There are a number of ways to acquire a culture of your very own.  If you are lucky, you may know someone who already has a culture that they can share with you.  One of the great things about working with a culture is that if you husband it carefully it will last essentially indefinitely, and produce more of itself as required.  This makes it easy to grow more to share with others.

If you do not know anyone who has a culture, or if you want to grow a different sort of culture (say rye instead of wheat, or whole wheat instead of white flour) you can buy cultures from many commercial sources.  Sourdoughs International ( is one of the oldest commercial sources of cultures.  The company was founded by Ed Wood, the author of World Sourdoughs from Antiquity (which has since been renamed Classic Sourdoughs) and sells a dozen or more different cultures collected from around the world.  Other good sources are GEM cultures ( and Cultures for Health ( which also sells through  All of these cultures take a little work to get started, but they will last indefinitely if cared for and fed properly.

Capturing the Wild Sourdough

The other option is to “capture” a sourdough of your very own by encouraging yeast and lactobacilli from the air (or another source) to grow in flour.  Capturing your own culture can be tricky (and frustrating) but if you can get one started it has the benefit of being (by its nature) something that will grow well in your home environment.  I have found greatest success starting in either Spring of Fall, when the temperatures are mild but not too cold.  In the summer the flour tends to mold before the culture develops properly, and in the winter it may be too cold for the yeast to grow well.  Most sourdough cultures grow best between 70 and 85 degrees.  The culture I captured seems to perform best at around 75.  If it is too warm, you can get off flavors from too rapid a fermentation.  If it is too cold, the yeast simply will not raise the bread very much, although it may produce a sourer flavor if given a very long rise.

To capture a sourdough, simply mix the flour of your choice (I used rye) and water to the consistency of pancake batter and leave it out in your kitchen, lightly covered with a towel or cheese cloth.  With luck, some combination of the yeasts present in the hulls of the grain and those in the air will “take”.  At least once a day, remove some of the mixture and add fresh flour and water in equal parts.  In 2-4 days (or thereabout) you should start to see bubbles forming in the batter, and it will give off a characteristic sour smell.  You will have the best results if you use whole grain, organic flour (the most likely to have wild yeast in the hulls) and filtered or distilled water (since chlorine may kill the bacteria desired) for  the capture.

If you have difficulty getting a culture to grow in this way, you can try introducing other sources of natural yeast.  Some fruits (particularly apples and grapes) have naturally occurring yeasts growing on their skins.  Try adding chopped up (with the peels), organic apples or organic grapes added to your water and flour mixture.  There are some that recommend introducing some source of lactobacilli such as yogurt or buttermilk, but I personally have had limited success with that.  I think that those bacteria are less likely to thrive in a counter top environment over the long term than those you might capture from the air.  You mileage may, of course, vary.

Baking with Sourdough

There are a number of good books on this subject (Mardewi; Wood; Reinhart), so this summary will be brief.  Add some of the sourdough culture to more flour, water, and salt until it looks like bread dough, and then let it rise and then bake it.  I have had reasonable luck bringing some starter culture to an event and adding flour, water, and salt as needed.  Once you have had some practice following recipes and gotten a sense for how the dough should look and feel you can go from there.

There are several options for baking at events.  If you have access to a wood fired oven it is ideal, but not often available at events.  You can build your own brick oven at an event and tear it down again without too much trouble, but that is outside the scope of this class.  You can also bake bread using a Dutch oven, or a cloche, both of which can be used with wood or charcoal fires.  The lid from a baker’s cloche can be placed on top of a pizza stone right over the coals of your fire pit.  The biggest challenge with a setup like that is keeping the fire low enough to not burn the bread.  With a sturdy cloche, you can place coals on top just like you would with a Dutch oven for even baking.

You can also use the starter with barley, oat, or other flours to produce soured flat breads.  If left to ferment overnight, the texture of the finished bread will be softer and more flavorful, if not much less dense.

Baking Without Yeast

Modernly most non-yeasted baking is done with baking soda (sodium bicarbonate) or in some rare cases with hartshorn (ammonium bicarbonate).  Both of those substances were unavailable during SCA period.  Without using any sourdough or other form of leavening, there are still a number of good options for baked goods.  You can fry flatbreads in a skillet, or bake crackers either in a skillet or in an oven or over some flat heated surface like a pizza stone.

For flatbreads very similar to the ones found at Viking Age Birka, Sweden, mix barley flour (or barley and oat flour) with a little salt and enough milk or water to form a soft dough.  I have made these with water, skim milk, whole mile, goats milk, buttermilk, and yogurt or skyr (a yogurt like cheese).  If you use a cultured product like buttermilk, you can let the dough sit for up to 1 or 2 days and it will become sour and softer, with a more open texture.  When you are ready, roll out pieces of the dough into 6 inch rounds, about 1/2 inch high, and put them on a frying pan or pizza stone over a low fire until they firm up, turning occasionally to prevent burning.  You can also roll similar dough into “tortillas” and cook them over the fire.  These are very good with ham and cheese, or other toppings.  Green pea flour was found in several examples of the thicker bread in Viking Age contexts (Hansson).  In the finished product most of the pea flavor is lost, but it adds a nice texture and extra protein.

Dough of barley or wheat flour, with or without the addition of some stone ground oats, rolled out thinly can be baked over the fire to the consistency of crispbread or crackers.

If you have eggs, you can make barley, wheat, or oat flour crepes in a frying pan.  These are very easy to make over the fire, and can easily feed quite a crowd.  They are good with butter and honey or smoked salmon and cheese.

Flours for Baking

When choosing ingredients for period baking, keep in mind the tools that were available in the period/place you are recreating.  For example, the Romans had flour mills on a commercial scale (Moritz), as did the Medieval English.  The Norse, in contrast, used saddle querns during the early Viking period and rotary querns later on.  A rotary quern can produce reasonably fine flour, but not as fine as our modern mills.  Modern “stone ground” flour a better choice for recreating Viking Age bread than very fine flours.  Stone ground barley, oat, rye and wheat flours are reasonably easy to find.  Bob’s Red Mill produces a wide variety of stone ground fours, available in many health/natural food stores.  Several other West Coast mills (Berkeley, Bellingham) produce good stone ground whole grain flours.  Bob’s produces stone ground “Scottish oats” excellent for breads.  If you have access to a grain grinder, this will produce the freshest flour and you can usually choose the grind.  Green pea flour, also obtained from Bob’s Red Mill, and is excellent for use in bread.  It is very finely ground and integrates well with other flours.


There are several options for baking bread without relying on commercial yeast.  You can use sourdough cultures to leaven your bread, or you can bake a number of different unleavened breads, either at home or over a campfire, using common equipment.

The biggest challenge in giving up commercial yeast is additional planning.  Working with sourdough cultures requires more time, planning, and practice than yeast baking.  In addition, longer rising times can take some additional planning at events to make everything come out in a timely fashion.    With a little practice, baking at events (or at home) can become quite practical and easy to do regularly.


Hansson, Ann-Marie. On Plant Food in the Scandinavian Peninsula in Early Medieval Times. Stockholm: Archaeological Research Laboratory  Stockholm University, 1997. Print.

Mardewi, Yoke. Wild Sourdough: The Natural Way to Bake. New Holland Publishing Australia Pty Ltd, 2009. Print.

Moritz, L.A.: Grain-mills and Flour in Classical Antiquity. Oxford Univ. Press, 2002. Print.

Reinhart, Peter. Peter Reinhart’s Whole Grain Breads : New Techniques, Extraordinary Flavor. Berkeley  Calif.: Ten Speed Press, 2007. Print.

Wood, Ed. World Sourdoughs from Antiquity. [Rev. ed.]. Berkeley  Calif.: Ten Speed Press, 1996. Print.