As a scientist, I really enjoy understanding things to their basic components. So, before jumping into making bread head first, I did a lot of research, read a lot of bread making books, and followed many online blogs. I eventually tried several recipes and I have to admit, the results were mixed. Not that my loaves of bread were bad, they really weren’t what I was expecting them to be. They didn’t have a deep and rich aroma, lacked flavor, and became stale fairly fast. It seemed that I was missing something. The recipes that I had tried used commercial yeast which was very convenient. It turned out it was maybe just too convenient. Commercial yeast has been used for bread making since the end of the 19th century (Fleischmann’s yeast was developed in 1868), but it was not available before and bakers had relied on something else to make bread for centuries, if not millennia. I thought that I should try to make bread the old fashion way, the way bread was made before the introduction of commercial yeast, using a natural sourdough starter made from scratch. The result? Perfect!
Making sourdough bread can seem overwhelming, as can attest the large amount of information devoted to it online, but it is actually fairly simple when you understand the basic principles. This is the purpose of this post and the following ones. They will describe my journey into demystifying sourdough bread and the observations I gathered along the way. In the last one, I will give you the step-by-step recipe that I developed for making sourdough bread.
I have a real attachment to making sourdough bread; I enjoy the process, I enjoy the result, and as a neophyte baker, I am linked through bread making to one of my ancestors, Nicolas Tardif who was a baker himself.
I find it comforting to imagine myself repeating the same steps and processes that my 6th time great grandfather followed more than 250 years ago. We are not only genealogically connected, Nicolas and I are linked over the span of eight generations in a more profound way, through bread making.
A lot of things have changed in the way we have been making bread since the 18th century when Nicolas made his own bread, but little had changed until then. Bread making before the introduction of commercial yeast relied on the power of environmental microorganisms, a mixture of bacteria and yeasts that I will refer to as microbiome throughout my posts. Although numerous on a microscopic scale, the microorganisms in the environment are not numerous enough on the macroscopic scale required to make bread, meaning that its activity is too small to have any substantial impact. As a consequence, the microbiome needs to be cultured in the form of what is referred to as a starter.
A starter is basically a naturally fermented mixture of flour and water that provides the necessary active microbial population of yeasts and bacteria required to generate the lifting power to proof the dough and give flavor to the loaf of bread.
There are many ways to create a starter, but they all have a common strategy:
Flour is mixed with water and the resulting mixture is left to ferment at ambient temperature.
A portion of the resulting culture is fed with more flour and the mixture is left to ferment again.
The feeding and fermentation steps are repeated until a mature starter in obtained.
At that stage, the mature starter can be kept indefinitely if fed regularly. It is believed that the Boudin Bakery in San Francisco has been using a starter that was generated in 1848!
Now, let's go through what is happening during the process of generating a starter.
During the fermentation, the naturally occurring yeasts and bacteria in the flour, water and in the environment (bowls, utensils, and hands of the baker) start to feed on the starch in the flour. During this process, starch molecules which are just big storage forms of a simpler sugar called glucose are snipped into its unit glucose molecules that the microbiome uses as energy source. During this metabolic process, the microorganisms use the energy produced to reproduce and multiply. The original population in the microbiome in the environment multiplies as it consumes all of the starch originally provided by the flour until all of the food source has been depleted. At this stage, more food needs to be supplied to the culture otherwise the microbiome will starve.
Feeding the culture is easy. It involves taking a small portion of the culture and adding it to a new portion of flour and water.
It takes multiple feeding and fermentation sequences in order to obtained a mature starter as the original microbiome needs time to reproduce enough to increase in proportion and to reach a maturity equilibrium with the good yeasts and bacteria feeding and multiplying happily and the other microorganisms dying off.
The figure below depicts the fermentation and feeding steps required to generate a mature starter.
Once a mature starter is obtained it can be kept indefinitely by repeating the feeding and fermentation sequence.
I prepared my starter back in January 2016 and it took about 10 days to reach maturity, 10 days during which the culture was fed once daily after the initial fermentation.
Notice in the picture on the right the difference in appearance between the original culture of flour and water mixed at Day = 0 and the mature starter at Day = 10.
The mature starter is slacker and it is bubbly. I will get to the nature of the bubbles in one of my later posts.
Another difference is in the smell. The original culture smells like wet flour while the mature starter smells more like yogurt. Some people have mentioned online that the smell of the culture sometimes goes through an unpleasant smelling stage which eventually goes away to be replaced by the smell of yogurt. I didn’t experience that, but I believe that it could be caused by the bad microbiome which over time dies off as the good microbiome becomes symbiotic (i.e. the yeasts and bacteria are happy together) and reaches maturity.
Getting a mature starter is temperature-dependent. I don’t remember the temperature in my kitchen back in January, but it was more likely between 65 and 70 degrees. This is probably why it took 10 days for my starter to reach maturity. Generating a starter at a higher ambient temperature would have taken less time as the microbiome multiplies faster at higher temperature.
During the fermentation steps, the culture increases in volume as the microbiome feeds on the starch in the flour and generates gases in the form of bubbles. You will also notice that the culture will taste more and more acidic (sour) as it ferments. I will explain the source of the acidity in another post.
The more the culture ferments, the more the microbiome eats until there is no longer enough food. At that stage there are no more gases produced and the volume of the culture decreases as the bubbles getting to the surface of the culture pop. A lot of people say that it is important to feed your starter once the culture has reached peak fermentation because at that stage the acidity of the culture is optimal. I personally don’t think it makes any difference whether the culture is fed before, at, or after peak fermentation as the feeding requires only a small portion of the culture to be added to flour and water and that the concentration of the acidity gets diluted in the process.
Once you have a mature starter, you will be able to keep it forever as long as you keep feeding it at regular intervals. I don’t make bread regularly so, instead of feeding my starter every day, I keep it in the fridge and feed it every other week or so. The cold temperature in the fridge slows down the feeding activity of the starter microbiome enough so it doesn’t need to be fed too often. However, when I want to make bread, I use a portion of my cold starter that I feed at room temperature for a couple of days, twice a day when it is hot, and only once a day when it is cooler. This process reactivates the microbiome which has been kept somewhat dormant in the fridge.
At this stage you should have a clearer understanding of what a starter is and the process required to create one.
Now let’s move on to the fun part, creating your starter!
Making a starter, instructions:
Whisk together 50 grams of bread flour and 50 grams of whole wheat flour into a bowl. With your hands, mix in 100 grams of filtered water. Scrape your hands clean and return the scrapped mixture of flour and water into the bowl. Cover the mixture with a towel and keep the bowl in the shade at room temperature until bubbles start to be visible in the mixture (this could take between two to five days depending on the temperature).
Note: tap water contains chlorine which can inhibit the fermentation process. Use filtered or even bottle water instead of tap water.
When bubbles have started to form, mix with a spoon until homogeneous. Take 30 grams of the mixture and dilute it into 60 grams of filtered water. Then, add 60 grams of a one-to-one mixture of bread flour and whole wheat flour (30 grams of each) and stir until the mixture is homogeneous.
You have just fed your culture for the first time.
Let the mixture, covered with a towel, ferment for 24 hours at ambient temperature.
Stir the mixture until homogeneous, take 30 grams of the culture, dilute them into 60 grams of filtered water, and mix in 60 grams of a one-to-one mixture of bread flour and whole wheat flour. This is the second feeding.
Let the mixture, covered with a towel, ferment for 24 hours at ambient temperature.
Repeat the feeding and fermentation steps for a few more days.