"This page was originally created to describe yeast and its properties. However, due to phenomenal demand, it seems most visitors want information on sourdough. So here it is.

Check out Panary Fermentation for a short history of barm or sour dough, and how it came about.

Introduction to Sourdough

Sourdough bread is made by replacing the yeast with a sourdough starter. Before we venture into the whole world of sourdough, let's explore what yeast is. Yeast is a one celled plant, (more exactly, a fungus) which digests the sugars and starches in flour. In the process, it produces alcohol and CO², which causes the bread to rise.

In the old days, people did not have access to dry, or cake yeast, and the only means of leavening bread was to set out a batch of flour and water, and literally letting it rot. And the rotten batter of flour and water is what today is called a sourdough starter.

From a scientific perspective, the sourdough starter is a living froth of lactobacilli and yeast which live off the complex carbohydrates in the flour. Although the lactobacilli don't contribute much to the leavening process, they do produce lactic and acetic acids which both promote a very acidic environment for the yeast to live in.

While yeast loves to live in very acidic places, other organisms don't, and thus, the lactobacilli provide a preserving environment for the yeast. Of course, the lactobacilli and the yeast interact in a much more complex way with each other. These symbiotic interactions are what make it possible to keep a sourdough starter around for long periods of time.

The acids in the sourdough starter are exactly what gives sourdough bread it's tangy flavour. The basics of how to make sourdough bread is straight forward once you have a starter.

For example, here's a great Sourdough recipe for two loaves:

Sponge:
1 2/3 cups unbleached bread flour
1 1/3 cups warm water
1/2 cup starter
Mix until mixture reaches batter consistency
Let sit until bubbly

Dough: Add the following to the sponge:
3 cups unbleached white flour
1 2/3 tsp salt

Mix until mixture reaches a dough-like consistency
Knead for 10 minutes
Let rise until doubled
Knock back
Cut into 2
Shape into loaves
Proof until a bit more than doubled in size

Bread:
Bake for 50 minutes in an oven pre-heated to 400º F.

Now, all you need is to learn how to make, keep, and nurture a sourdough starter. If you have read this page all the way to this point, then you should go to the next step, and become a real expert by learning all about sourdough.

Become a Sourdough Expert

Guide to getting a starter
This is a short guide on how to get a hold of a starter. It includes information on how to make your own from scratch, and on how to generate a starter from a batch of innoculent received from a friend.

Guide to using a starter
Using a starter can be tricky. This guide will help you understand a bit more how to maximize your starter's returns.

Guide to keeping a starter
Once you have a starter, here's a quick maintenance guide on how to care for it, and on how to revive it if you've left it in your fridge too long and it ends up resembling some biology experiment gone awry. There is also a short guide on how to dry a starter to be used later to revive a new starter.

Getting a starter
Before you can bake a sourdough loaf, you need to have a starter, which you can get in one of three ways:

Make your own from scratch
Get some from a friend
Buy a starter

Guide to making your own starter from scratch
There are many ways of making your own starter. Here are a few different ways of doing it: (No offence to the sourdough purist, but by our definition, If the final product ends up to be a mixture of lactobacilli and yeast, then you have a starter, regardless of how you started it.)

1. The purist approach
2. The Northern European purist approach
3. The natural innoculant approach
4. the shortcut approach

1. The Purist Approach
Some people will argue that this is the only way of creating a pure sourdough starter, and they may be right. Sourdough is like cheese: there are different cultures out there, and the only way of creating a unique culture of your own is to start with just flour and water, and invite the local micro-organisms for a royal feast.

Mix 1 cup of water and 1 cup flour in a bowl, cover, and put into a warm place.
After 1 day, add another 1/2 cup water, and another cup flour, and put into a warm place.
Repeat this procedure until the batter starts to smell sour, fruity and yeasty. Then, refrigerate.

2. The European Purist Approach
Scandinavians, Russians and Germans came to recognize that certain flours produce much faster fermentation. A case in point is Rye flour, and this flour will invariably produce a very viable starter in a very short amount of time. The procedure is identical to the purist approach, except that Rye flour is used instead of White flour.

Mix 1 cup of water and 1 cup rye flour in a bowl, cover, and put into a warm place.
After 1 day, add another 1/2 cup water, and another cup flour, and put into a warm place.
Repeat this procedure until the batter starts to smell sour, fruity and yeasty. Then, refrigerate.
Note that since Rye ferments so fast, it is possible to take the fermentation process too far and end up with a slurry of acetic acid. In that case, dump out 3/4 of the starter and add 1 cup flour and 1 cup water, let sit for 12 hours, and then refrigerate.

3. The natural innoculant approach
The idea here is to use a natural innoculant such as grape skins on which wild yeasts reside to get the starter going. The recipe is the same as the purist approach, except that the batter is innoculated with grape skins, or other fruit skins or leaves. The assumption is that there are yeasts which reside on the skins of fruits or on the surface of leaves, and the hope is to introduce these yeasts into the batter to get it started faster. This assumption is quite reasonable since, contrary to popular belief, yeast is less likely to enter the batter through the air than on the surface of some substrate, such as flour or grape skins.

Mix 1 cup of water,
1 cup flour,
grape skins or other fruit skins or leaves in a bowl,
cover, and put into a warm place.
After 1 day, add another 1/2 cup water, and another cup flour, and put into a warm place.
Repeat this procedure until the batter starts to smell sour and fruity. Then, sift out the grape skins, and refrigerate.

4. The shortcut approach
The idea here is to use commercial cultures to get the starter going, and then hope that the organisms will evolve into a symbiotic relationship. The recipe is the same as the purist approach, except that the batter is innoculated with commercial yeast and yoghurt or buttermilk cultures.

Mix 1 cup of water,
1 cup flour,
1 tsp active dry yeast, and
1/3 cup buttermilk or yoghurt in a bowl,
cover, and put into a warm place.
After 1 day, add another 1/2 cup water, and another cup flour, and put into a warm place. Repeat this procedure until the batter starts to smell sour and fruity, which is usually within 2 days. Then, refrigerate.

Getting some from a friend
Why not get some from a friend? All it takes is as little as a tablespoon. Follow this recipe to start your own batch using a small batch of inoculant from your friend.

Mix 1 cup of water, 1 cup flour, in a bowl, add whatever amount you got from your friend, cover, and put into a warm place for 12 hours.
Then, if the batter starts to smell sour and fruity, which is almost always, refrigerate the mix. If not, add another 1/2 cup flour and 1/2 cup water, mix, and wait another 12 hours.
Repeat this procedure until you have a fruity and yeasty mixture, and refrigerate.

Buying a starter.
If you'd rather buy a starter than making your own, then keep checking this section. We are working on building a special buying guide for sourdough.

Using your starter
Now that you have a starter, it's time to use it. This short guide will explain you the many subtle and generally unknown aspects of sourdough. What you will learn here is the following:

The main two ways of using sourdough starter in baking
How to maximize the leavening and flavour of sourdough
The effects that using other flours has on your starter
The effects of sourdough on crust and bread consistency

Main two ways of using a starter
The traditional way of using a starter is to first "proof" the starter by taking it out of the fridge, and feeding it a couple of times while it sits in a warm place. Once it becomes foamy, it is ready to be used for baking. This method doesn't require the use of a sponge as described in our Introduction to Sourdough. Thus, once you have a "proofed" starter, you can then mix all the ingredients at once to make the dough. In other words:

4 2/3 cups unbleached bread flour
1 1/3 cups warm water
1/2 cup starter
1 1/2 tsp salt

Mix until mixture reaches a dough-like consistency
Knead for 10 minutes
Let rise until doubled
Knock back
Cut into 2
Shape into loaves
Proof until a bit more than doubled in size
Bake for 50 minutes in an oven pre-heated to 400 degrees F.

But there really is no reason whatsoever to proof the entire starter container just to make a loaf of bread. The alternative is to remove the starter from the fridge just long enough to take out whatever amount you want to inoculate a sponge, let's say 1/2 cup, and then feeding the starter by replenishing what you took out, let's say 1/2 cup water, and 1/2 cup flour. After that, put the starter jar right back into fridge. Make a sponge using the half cup of starter, all of the liquids in the recipe, and half the flour, and proof the sponge, i.e. wait that the whole batter-like mixture is nice and bubbly. Only then, add the rest of the flour, salt and other dry ingredients, and make the bread. See the recipe in the introduction to sourdough as an example.

This method also presents another advantage if you bake only about twice a week. The time it take the wild yeast to reach peak leavening activity depends on both temperature and how often you use your sourdough. If you keep your sourdough jar at room temperature, and you feed it every day, you will notice that the culture will go through its cycles ever more quickly. That also means it will go dormant much faster. With the starter being in the fridge all the time, this cycle is much slower, and feeding it once or twice a week is enough to keep the starter very active.

Maximising the leavening and flavour
The previous discussion naturally leads us into the next topic, namely how to maximize the leavening power of the starter. To understand how the starter works, let's look at the life cycle of the starter in closer details. Assume you've not used your starter for a while, and you've just taken out 1/2 cup of it, and mixed that with some fresh flour and water. What you have done is added a bunch of nutrients, and the micro-organisms in your mixture, having noticed all the extra food, will start to multiply. First, the yeast reaches its peak activity, say within 2-3 hours. Then, the lactobacillus peak, sometimes up to 9 hours later. Eventually, the organisms run out of food, and the mixture will once again go dormant.

So the easy rules of thumb to follow are: give the micro-organisms food in the form of flour or sugar. This starts the cycle, which is 1) yeast peaks, and 2) lactobacillus peak later. Every time you feed, this cycle starts over. Every starter has different times for these cycles. The average is that it takes 3 hours for yeast to peak, and 10 hours for the lactobacillus to peak. But there are starters with yeast times as short as 1 1/2 hours, and as long as 8 hours. It all depends on the culture you end up with. Now, let's translate all of that info into practical tips on making bread. The idea of using a sponge is simply to activate the yeast and lactobacillus. The trick is then to time it just right and add the remaining ingredients in the recipe just so that the yeast doesn't go dormant, but reactivates to give your bread that good final rise.

Example: let's say you're one of those puckering sour taste lovers. You want bread that makes your tongue turn inside out. Here's the trick:
let your sponge sit long enough so that the lactobacilli really have plenty of time to reach peak activity and make all those acids that are going to flavour your bread. Then, add the rest of the ingredients, and this time, time it so that the final rise takes place when the yeast activity peaks.

Suppose you don't care much for too sour of a taste. Then, keep the sponge around just long enough for the yeast to reach peak activity, and then add the remainder ingredients to keep that activity going. The bread will still be sour, but much less so.

Two major factors will affect the way your culture behaves, and thus change the flavour: what you feed it, and how warm you keep it. The temperature is a real important factor: proofing at about 100 F will lead to maximizing the acetic acids in the bread, while a lower temperature around 80 degrees will generate more lactic acids.

Finally, do realize that the enzymes produced by the starter will affect the consistency of your bread, and specially the crust. It is a well known secret among professional specialty bread bakers that the best way to obtain a chewy crust is to "age" the dough. Some bakers age their dough as long as three days at very low temperatures (78-85 deg. F). That will make the crust very hard and moist. The best way to proof your sourdough bread is to get a plastic box with a semi-tight lid. Put some warm water at the bottom, and put the dough to be proofed on baking sheets. The box will retain the moisture, so that the dough won't dry out during the long, cool proofs.

Keeping a starter
Now that you have a starter, it's time to worry about how to maintain it. Just follow these three guidelines:

Keep the starter in a glass container.
Feed it at least once a week.
Wash the glass container out every couple of months

Metal containers are out because the acids in your starter would quickly corrode your container. Whatever anyone says, don't use plastic containers. Plastic is an organic material, and so are the enzymes in the starter. The plastic will absorb whatever organic compounds made by your cultures.

As long as you feed the starter once a week, you will keep the lactobacillus active, so that they produce plenty of acids that act as preservatives for your starter. If you plan on not using the starter for an extended period of time, put all of the starter in a bowl, and wash out the jar before putting all of the starter back. That way, there will be no dried up flour caked on the insides of the jar. (The stuff caked on the sides is usually the first stuff to go mouldy). Do this wash procedure every few months even if you use the starter on a regular basis.

There are two ways to store a starter in a dried form. 1) Dry the starter on a sheet of wax paper, 2) Dip a cloth into the starter, and let it dry. Either methods require you to first bring the starter to full active status. That means, feed the starter, and wait for the yeast to reach peak activity before drying it. In the case of a cloth, once the cloth is dry, fold it up, and store it away in a cool, dark place. In the case of the wax paper, scrape the dried starter into a jar, and store in a cool, dark place.



 

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