The basic principles of sourdough making.
Essentially sourdough starter is a mixture of flour and water, rich in bacteria and yeast, either added or naturally occurring from the environment, that is used to make sourdough bread. Most bread cultures are used to control the indigenous bacteria naturally present in the flour, which might produce unwanted characteristics such as excessive sourness or a spoiled taste. Adding the cultures will ensure a uniform and more complex flavour development with minimal batch-to-batch variations.
The variety of flour used influences the characteristics of the sourdough and it is possible to make sourdough with wheat, rye and other types or mixtures of flours. Other important parameters influencing the attributes of the cultures are time and temperature during the processing. Additionally, it is possible to produce sourdough adding milk, oil, sugar and salt, which also will influence the result.
Most commercial bakeries start off with a fresh batch of water, flour and culture each time, so as to ensure no cross-contamination and completely consistent results from bread to bread, day-to-day. At home, you may want to follow the directions below and keep your sourdough going for as long as you choose.
Wild fermentation is a different thing altogether. That is when you mix flour and water together and then let it sit for several days and wait for wild yeasts and bacteria to develop. These microorganisms were either already in the flour, or in the air in your environment. While this does work, as you can imagine this is not within your control. If it works, that’s great. If not, you will get something that does not look or smell great and you will have to throw it all away and start again. I have done a few fantastic wild ferments and had one very smelly disaster.
There are two basic steps in making sourdough bread.
Making your sourdough starter (pre-dough or mother).
First, you have to make up your sourdough pre-dough, using flour, water and bacteria. In some cases, you may also add some sugar and/or salt, which will affect the flavour of your final bread. Please see directions for full details on how to do this step. Once you have made your pre-dough you are ready to take a portion of this pre-dough and make your bread, following the recipe of your choice. The remaining starter can be stored in your fridge for later use.
Maintaining your pre-dough for years to come.
The second step in sourdough bread making is to maintain your pre-dough. While the remaining pre-dough can be stored in the fridge, it will need to be maintained by feeding it once a week. Your pre-dough is alive and it needs to be fed with a mixture of flour and water.
For example, if you started out making a kilo of sourdough pre-dough and you used 500 grams in a bread recipe, you would then need to make 500 grams of 50% flour to 50% water mixture and feed this to your pre-dough by mixing it into the remaining 500 grams of starter.
If you do not make bread one week, and therefore do not use any pre-dough, you will still need to feed your pre-dough once a week. It is common practice in this instance to discard a portion of your pre-dough and feed the remaining pre-dough, keeping it alive.
If your pre-dough is left for too long without being feed, it will die. Don’t panic. If this happens, simply start again with a fresh batch of flour, water and bacteria. As the bacteria (culture) is stored in the freezer it will be alive for years to come and can always be pulled out to start another batch if necessary.