Making sourdough is easy and cheap. There are many ways to do it, for the simplest you do not need more than flour and water (and time, of course, as for all good things).
What we are going to try to do is create the right conditions to "capture" the yeasts and bacteria present in the air and food. Later, we will use this sourdough to make bread. Before industrial yeast (which is barely a century and a half old), bread was always leavened with natural yeast. Natural yeast gives bread a flavor that commercial yeast simply cannot. In addition, it alters all the characteristics of a loaf: crumb, crust, duration, preservation of humidity, etc.
To create this house for our “bugs” we need a container, an old jar of jam will do; Being made of glass, we can see at all times how nature is doing its job. The bugs will feed on the flour and release gases (which then get trapped in the bread as bubbles in the crumb). For this reason we will make a hole in the lid of the jar, so that it is not 100% hermetic.
The process lasts 4 days; During this time we will always try to have the pot with the same amount of sourdough (approximately half full, with a consistency of dense pasta). Since every night we will have to "feed" our host, we will have to discard half of the dough to make room for the new food.
Let's go there!
We will mix the same amount of flour and water. How much? it depends on your boat. Just try not to make the pot more than half full (you'll see why later). The water does not have to be cold or hot, at room temperature it is fine. You can use bottled water or just let the tap sit for a while to lose its chlorine. We will use whole wheat flour since the yeasts are on the surface of the food (husks of wheat grains, skin of grapes, etc.); the "white" flour has had the shell removed, so it is less likely to have the bugs we are interested in. The flour in the photos is wheat, the rye flour is even better.
Mix the flour and water and let it rest in a quiet place (it should not be in a hot place). I made this sourdough in a warm December in Barcelona (on the street there were from 9º to 17º, at home something else, of course).
I make the sourdough at night, when the house is quiet. During the four days of the process it is easy for me to remember that I have to feed the dough before going to bed.
After 24 hours there are no major signs of activity. The dough has settled a bit, and some brown liquid floats to the surface. If you look very hard, you can see tiny bubbles in the dough (but you have to look closely).
We throw half of the dough and add flour and water until the pot is half full again (like yesterday), stir well. We return to let the dough rest for a day in a quiet place. This day (in anticipation of what is to come) I make a mark on the boat with a black marker; let's see what happens.
On day 3 there are already signs of life. The dough is full of bubbles and has noticeably swollen, the level has risen about 2 cm above the mark I made the night before; this is going. Also, there is a smell, "that" smell. It is not an unpleasant smell, it is a smell of life, a new and unforgettable smell.
As the day before, we discard half of the dough and fill, again, the pot halfway with flour and water. Since you probably didn't fill the bottle to exactly the previous day's marker mark, erase it and make a new line on the glass.
Day 4 is a great day, a day that we will never forget. Today we have finally managed to have the sourdough ready.
The appearance of the pot is spectacular, the dough has doubled in volume, and it threatens to slip out of the pot. The mark we made with the marker is just a memory in the middle of the glass. Big gas bubbles are noticeable all over the boat, it's ours!
Now that we have the sourdough ready to give us delicious loaves of bread, we can do several things:
- Use it, as is, in making bread.
- Put it in the fridge until we want to use it (before putting it in the fridge, we feed it again and wait for it to bubble). With the cold of the refrigerator, the sourdough "goes numb" and does not need to be fed daily. So it can last for months. It is totally normal for it to settle and create a thick layer of grayish liquid. When we want to use it, we just have to bring it back to room temperature and feed it.
- The third option is to go "clarifying" it with "white" flour to make it more versatile: a white sourdough makes white and whole bread; A whole grain sourdough only makes whole grain breads, as it stains the whites (not that it can't be made).
I have chosen to clarify it, so that it is white, so I can make 2 different types of bread from the beginning; White breads and whole grain breads, thicker and darker. To clarify it, we simply toss half the dough again and fill the pot with flour and water. The same as the previous days, but this time with white flour.
Things that can happen
- The sourdough is too runny and the water separates from the flour. Very simple, the next day correct the amounts by putting less water. The dough will be thicker.
- The sourdough is very dense and creates a very dry crust. Very simple, the next day readjust the amounts by adding more water. The dough will be more liquid. It may be in a too hot place and that is why the scab is made.
- No change happens for 3 days (or more) and it smells bad. Bad "bugs" may have taken over your sourdough. Peace of mind, nothing happens, throw it all in the trash and start over (it has happened to all of us). If after 3 or 4 attempts you see that you never succeed, you can try putting a tablespoon of plain (skimmed) yogurt in the initial mixture. Yogurt is acidic and will keep the bad critters at bay until the good ones arrive.
- It is very hot and the sourdough reacts very quickly (it does not need 24 hours to complete each phase of the process). This can happen if it is summer or you have very high heating. In this case, you will have to advance the steps. It is more cumbersome because it may require being more aware of the dough (feeding it 2 times a day). However, even if you see a lot of activity, the first time try to follow the steps described and then draw conclusions.