Commercial "baking" yeast is a single kind of organism that belches a lot of gas really fast and transforms grain into something that's even less good for you. Sourdough is two organisms, wild yeast and bacteria, in symbiosis. Together they transform the grain to make it more healthful, more digestible, and also resistant to getting moldy or stale. Many people with wheat allergies or "yeast" allergies have no problem eating real sourdough. And it's free!
How Does It Work?
With sourdough, you are keeping and feeding a population of friendly yeast and bacteria, called a "culture", or a "starter". The population rises and falls, depending on where you keep it and what you feed it. When you make a loaf of bread, you are carefully managing a population explosion. The sour flavor comes from acids made by the yeast and bacteria, and when it gets really strong, that does not mean the sourdough is strongly active, but that it is depleted, that the population has already eaten its food and collapsed.
What You Need
. Most grains will work, though only wheat has enough gluten to hold together big air bubbles and make a fluffy loaf. White flour has the same effect on sourdough that it has on you: it appears to work, but it's missing important nutrients, and over the long term it leads to poor health. I use a mix of home-ground whole wheat flour and white flour.
. The more filtered, the better. At the very least it needs the chlorine taken out, which you can do just by setting it in an open container for a day or so.
A Glass Jar
to keep your sourdough in. The wider the mouth, the better. Glass is ideal for sourdough. Pottery is good too, and probably wood. Plastic is bad and metal is the worst for sourdough because it reacts with the acids. Stainless steel might be okay for bowls and it's fine for utensils.
Bowls and Pans
, depending on what you're making.
or at least a stove.
Some people have sourdough cultures that are more than 100 years old -- that is, they have been separated from nature for more than 100 years. I wonder how the yeast and bacteria have changed in that time, whether they're getting domesticated, losing their edge. So I like to catch a fresh culture at least once a year. People ask me for starter as if it's something precious that they couldn't get any other way, but catching sourdough is easy, easy, easy! Books make it sound like it's difficult and complicated and takes a long time. Using the following system, I have never once failed, and it usually takes less than three days.
Mix equal volumes of good flour and good water, and set it in a glass jar in a warm place. Some people say to keep the lid off so yeast falls into it from the air, but evidence suggests that the yeast is already in the flour, so I just put the lid on loosely so it can breathe. A loose lid is easier than cheesecloth and works just as well. If you do keep the lid off, put it on a high shelf where less bad stuff will fall into it.
What you've got now is a race between good and bad microcritters to take over your jar of food. If the sourdough wins, it will smell sour, probably with a layer of brown liquid on top, but not moldy or rotten. If it gets moldy or rotten, it's almost certainly because you're using low quality flour or water. If it doesn't do anything, it's probably because of irradiated flour, chlorinated water, or a location that's too cold. Rye flour is said to work better for starting the yeast, and then you can switch to a different flour if you want. Another trick is to put it in a warm place, but not above body temperature. Another trick (don't tell anyone) is to add a tiny bit of your saliva.
I'm told that you can catch different strains of wild yeast and bacteria that behave differently, but I've done it many times and never noticed a difference. If you add commercial yeast, you'll just get a culture that's dominated by commercial yeast and not sourdough yeast. I've heard that you get something good if you use the white mold that grows on grapes.
So: flour, water, jar, wait a couple days, it turns sour. By the time you're sure that your jar has been taken over by the good stuff, it will be much too depleted to use. So you need to dump out almost all of it, and add fresh flour and water, again in roughly equal amounts, and stir it well. Then it will rise, and be good enough to use, but still not as good as it will be after one or two more cycles (see below).
After you've caught the right yeast and bacteria, you want your jar of flour/water to get bubbly and increase at least 50% in volume. If it doesn't bubble, smell it. If it smells like nothing, or like flour, it needs more time and warmth. If it smells really sour, but isn't bubbling well, refresh it again: throw out all but a little bit and add more flour and water.
What you're aiming for is a jar of what I call peak
sourdough. When sourdough is at its peak, it has risen to maximum volume, it's full of living yeast, it's thick enough to hold air bubbles, and it's not yet very sour. That's when it's perfect for eating, or for going to the next step if you're making bread. When it passes its peak, it falls in volume, the bubbles go out, the yeast population crashes, and it gets too sour -- too much acid and not enough sugar.
Past-peak sourdough is great in a pie crust or anything leavened with baking powder, but it's difficult to use it for bread. You have to add a lot of flour and water (compared to the quantity of sourdough) to dilute the acid, and then wait longer for the next rise. Do not mistake sourness for rising power! The surest way to get your bread to rise is to build up to it, like a motorcycle jump, with good bubbly rising at every step.
Taking Care of Sourdough
It's not as hard as a baby, or even a dog, but it requires much more attention than a plant. It's a bunch of tiny living animals that need frequent food. If you neglect them, they'll eat up all the food and die down to almost nothing, and possibly other organisms will take over. But the nice thing is, they do everything slower at lower temperatures. Unless you're eating sourdough at every meal, or your kitchen is cold, you'll need to keep it in a refrigerator.
To feed it, remove almost all your sourdough (ideally you will eat it) and add more flour and water to what's left in the jar. Some people say to remove only half but this not only gives you less sourdough to eat, it leaves an overly sour acid bath for the next batch. You can remove 99.99% and your sourdough will still be alive -- it will just take a long time to build its population back. I remove about 90% -- I just dump it out and leave in whatever clings to the sides of the jar.
When you add the flour and water, you'll have to learn through practice how thick to make it, depending on your flour. Some flour gets thicker after it soaks in water, so you have to start it runnier, and some flour gets runnier so you start it thicker. Lately I've been going thicker, so thick that when it's finished, I get it out by holding the jar upside down and maybe banging on it. If you need a spoon to get it out, it's too thick. If you're getting a layer of water, it's too thin. Also, as you'll quickly find out, you should only fill the jar about two thirds full, to give it room so it doesn't explode or run out everywhere. I always add the water first, and shake up the jar to evenly distribute the dregs of living sourdough, and then add the flour. And if I'm making bread that's part whole wheat and part white, I add the whole wheat now so it can benefit from longer soaking.
It will often happen that you don't use your sourdough in time and it gets flat. The only thing to do is "reset" it: save a little bit, feed it fresh flour and water, and throw the rest out, or use it in something other than bread. You can save sourdough that has been neglected for a long
time. Even if it's turned black on top and smells totally nasty, there's probably still some living yeast in there. Take a bit out and feed it fresh flour and water, and see what you get. And if it's dead, just catch a new one.
Zen And The Art Of Sourdough
Sourdough exercises your foresight and awareness. For example, at noon, I anticipate that I will make a waffle at 10PM, and I know that I used and fed the sourdough last night and put it straight in the fridge, so it's nowhere near ready. If it's a hot summer day, I should wait until about 6PM to take it out, but if it's cold I need to take it out now to give it all day to get to its peak. If I need it fast, I'll put the jar in some warm water. Another trick is to leave it out, bring it close to its peak, and then (if you remember) put it back in the fridge, where it will remain ready to use for maybe a day -- if you remember! What I'm getting at is, you have to devote a permanent bit of attention to where your sourdough is in its life cycle, kind of like one of the programs that runs in the background on your computer.
Sourdough Pancakes and Waffles.
I just take sourdough that's right at its peak, and pour it straight on a hot oiled pan or waffle iron. That's it! If you want to mix in other ingredients, or if you stir it at all, you will pop the bubbles and you'll have to stir in some baking powder to get it to rise enough. A waffle, because of the greater surface area, is more forgiving than a pancake. Even when I do it perfectly, my pancakes are a little gummy, but imperfect sourdough can still make excellent waffles. You'll be surprised how good it tastes with nothing but flour, water, and friendly microbes. Put on some pasture-raised butter and real maple syrup, and you've still spent less money than with white-flour white-sugar aluminum-baking-powder hydrogenated-oil restaurant pancakes. Almost any kind of flour will work.
These are the next easiest thing. You still don't even need a bowl. Clear a space on the countertop or a big cutting board, pour some flour down, pour some sourdough on top of it, mix it with your fingers, fold it over a few times, add some more flour, and roll it out with a rolling pin or wine bottle. It will take some practice to get the proportions right and keep it from sticking. The more gluten is in your flour, the easier it is. With anything but wheat, you'll have to settle for very small tortillas.
Sourdough Pie Crusts.
If you want a light, flaky crust, forget sourdough, and see my recipes here
. A whole grain sourdough crust will not have light texture, but it will have more interesting flavor and be better for you. I recommend whole wheat pastry flour. Whole wheat bread flour is slightly easier to work with but the crust will be brick-like, and non-wheat is so fragile and sticky that I wouldn't even try to roll it out, but just press it into the pan.
In a bowl, cut some butter into some flour. You can use your fingers, a pastry blender tool, or my new favorite method is to use frozen butter and a cheese grater. Most recipes call for a whole stick or more, but if I'm eating lots of pie, I might use as little as half a stick. For vegans, I recommend palm or coconut oil, or non-hydrogenated margarine like Earth Balance. Liquid oil works too, but you'll probably have to roll the crust out between sheets of waxed paper. Just dump the oil in at the same time as the sourdough. I recommend extra virgin olive or sesame. Canola is not terrible, but its healthful reputation is pure marketing.
Now add the sourdough. Two cups (16oz, half a liter) of bubbly sourdough should be enough for a two-crust pie, or more than enough for a single crust. Mix it in with the flour, don't work the dough too much, get it firm but pliable, and roll it out with more flour. Pie crust is not easy! For a lot more info, check out my pie crust
In a bowl, cut butter or other solid oil into flour, then mix in some baking powder, and then dump in the sourdough. If you're using liquid oil, mix the flour and baking powder and then add the oil with the sourdough. It's basically like a pie crust, except you need baking powder to make the biscuits rise. For a 16 oz jar of sourdough, I'll use one or two teaspoons of baking powder. Have your oven already heated and your pan already oiled, and when you add the liquid stuff to the dry stuff, mix it quickly and gently, fold it over a couple times, and form the biscuits. I either make a fat disc and cut it into six wedges, or if the dough is too sticky, I just drop six gobs of it in the pan. Bake it at 350-375 F for 20-30 minutes.
Other Soda Breads
can be made by varying the biscuit recipe. For example, to make scones, add sweetener. For blueberry muffins, add sweetener and blueberries and cook them in a muffin pan. For banana bread, add some mashed up bananas and maybe walnuts, and make one big thing instead of several little ones. For most of this stuff I'd increase the baking powder to a tablespoon -- it's full of sodium but it's your insurance against the bread coming out wet and gummy.
I use a blend of home-ground whole red wheat and white flour. As you move into whole grains and low-gluten grains, your bread gets healthier, but it gets harder to knead, harder to raise, denser, and more prone to being gummy.
For bread, you have to manage two, maybe three yeast population blooms in sequence. The first one is just getting your working jar of sourdough bubbly. The optional second one is called the "sponge" -- basically you're making a larger quantity of peak sourdough.
In a big glass bowl, mix some sourdough (called "starter" in this context) with a lot of flour and water. There are different ideas about how thick it should be, but probably about the same as the starter. Then the trick is timing -- knowing/controlling/detecting how long it takes to build a large and still growing yeast population. If you start with a lot of sourdough already at its peak, and the room is warm, it might take only a couple of hours. If you want to stretch it out longer (for example overnight), use a smaller amount of starter, or put it in a cooler place.
It's not easy to tell when a sponge is done. Unless it's stiff, it won't rise much. The purpose of the sponge is not to make air, but to grow a higher yeast population, and also to give it more time to transform the flour. The best way to measure your sponge is by smelling and tasting it. It should be yeasty and just a little sour. Then you want to take that population momentum and throw it into the next rising: add a lot more flour to the sponge, but no more water, knead it into a loaf, raise it for several hours, and bake it. With commercial yeast you usually punch down the loaf and let it rise a second time, but it's difficult to get an extra rise out of sourdough.
If I'm making only one loaf I don't use a sponge. I just take my jar out of the fridge at night, add a bunch of fresh-ground whole wheat flour and a little white, some water, and set it out overnight. In the morning I spread a bunch of white flour with salt on the counter, dump the jar on, knead it, raise it, and bake it. A recent trend is to make wet dough that's not kneaded at all. This only works with all white flour! The more whole grain flour is in your mix, the more important it is to knead it, and the more risky it is to make it wet. Wet dough rises faster and has softer texture, but it might collapse or be gummy. Dry dough won't collapse but its texture will be dense and powdery.
There are different kneading techniques, but the only important thing is that you repeatedly fold the dough over on itself. The dough will probably get sticky and you have to add more flour. As a beginner, I used to do this for half an hour thinking this must be the last time I'll have to add flour, but it kept getting sticky again. Now I'm more aggressive about adding it at the beginning. You're aiming for dough that is silky-smooth and elastic, but not so dense that it's hard to work with. The less gluten you have, the denser it will get before it stops being sticky.
At this stage you can also add other ingredients. Salt is not necessary, but almost everyone adds it for flavor. You can also add sweetener, oil, herbs, or other kinds of food. It will take some research and experimentation to find out what effect these will have on the rising and the final texture of the bread.
When my dough is ready to rise, I put it in an oiled and floured loaf-shaped bread pan. If it's dense, you can put it on a flat baking pan where it will form a nice round loaf without spreading out too much. If you're really good, you can raise it and then transfer it to a hot baking brick without collapsing it. The new trend is to flip your risen loaf into a hot dutch oven, but again, this will probably only work with white bread.
In any case, before baking it, you have to know how long to raise it. Once again you're looking for the point where the yeast has eaten its food and transformed the dough and made lots of bubbles, but it hasn't started declining, which will make the loaf collapse because the air bubbles are no longer being filled. Six hours is typical, but it could take anywhere from 2-24 hours, depending on the temperature, the starting yeast population, and the density of the loaf. This is the hardest step for beginners. I would say, watch the bread and try to guess when it's risen about as much as it will rise. White bread might double in volume but whole wheat probably won't increase more than 50 percent.
Now you put it in a hot oven, where ideally the warmth will give the yeast one final push of growth, and then the heat will expand the air bubbles and fix them in place in a not-too-dense loaf. I like to start at 425F, then turn it down to 400 and bake about 30 minutes. Professional bakers go much hotter and also use steam. The test for doneness is to take the loaf out and tap the bottom. It should sound hollow. Happy eating!
The nice thing about pizza dough is it's so flat that there's no danger of it collapsing, so you can get away with a wetter dough. Otherwise it's just like regular bread. I put some olive oil in the mix, shape it and raise it in the pizza pan I'm going to cook it in, and when it's ready, just put the toppings on and bake it. A layer of coconut oil and a dusting of flour underneath the dough will help keep it from sticking.
Make a large batch of bread dough (as above, wet dough is OK), and then instead of shaping it into a loaf, roll it out in a big square, maybe 8 inches by 24 inches (20x60 cm). A great trick is to use cinnamon instead of flour to roll it out. Then spread sweetener, nuts, raisins, whatever, making sure to go all the way to the edges, and roll it up from short edge to short edge, so you get a short thick cylinder. Cut it into about six pieces, and arrange them in a pan with high edges and just a little extra room, so when they rise they will fill the pan. Rise and bake.
You can also form bread dough into round flat shapes and fry them! So if you're squatting, camping, or living in your car, and you have a stove but no oven, you can still have homemade bread.
An extensive Sourdough FAQ
Naturally Leavened Sourdough Bread
and Naturally Leavened Bread
cover the health benefits of sourdough over commercially yeasted bread.
Against the Grain
is about all the ways that wheat has been corrupted in the industrial age, and how it can be made more healthful through sprouting or souring.
A page on the advantages of fresh stone-ground flour
, with a small section on sourdough.
And here's a more general piece I wrote on How To Eat Better
(last updated november 2014. public domain, anti-copyright)