One of the most important jobs at our bakery is feeding our sourdough starters. We do it twice a day; it is the first and last job, every day. We use two starters at the bakery – one wheat and one rye, which we use for different bread formulae. It is very easy to make a starter (also known as the mother, levain or biga): simply mix together flour and water, and give it time. I recommend using organic wholegrain rye or whole-wheat flour. They contain more wild yeast and bacteria than processed flour, which helps to accelerate the fermentation process.
Your choice of flour is important. While researching for this book I experimented with several different flours, including a supermarket brand ‘wholemeal’ flour. This flour produced no aroma or flavour, and the starter oxidised before it was able to ferment, with black spots appearing throughout the mixture. Eventually it started to ferment, but the aroma was almost non-existent, and the flavour was flat and bland.
A healthy sourdough starter contains two types of organisms: yeast and lactic-acid bacteria. The single most important factor when building or maintaining a starter, and when mixing your bread dough, is temperature. The yeast and lactic-acid bacteria are most active between 22˚C and 30°C (72˚F and 86°F), and the ideal temperature is around 26°C (79°F).
To achieve the desired temperature for your starter or dough, multiply your ideal temperature by two and then subtract the air temperature. The resulting number will be the temperature your water needs to be. The water temperature balances out the difference between the flour temperature (which tends to be the same as the air temperature) and your desired starter or dough temperature.
Let’s say the temperature in your kitchen is 19°C (66°F). To achieve a starter or dough temperature of 26°C (79°F), do the following calculation: 26°C (desired temperature) × 2 = 52 – 19°C (current air temperature in your kitchen) = 33°C (the temperature of the water needed for your starter, or dough)
To achieve the required water temperature, just run the hot tap and collect some warm water, then check the temperature and adjust as necessary by adding more cold or hot water.
It takes five to seven days to make an active starter full of good bacteria and wild yeast. You want a starter that’s full of bubbles and has the characteristic smell of fermentation. That’s how you know you’ve got a good balance of yeast and bacteria, and that they are very active. Keep your starter covered as it ferments, to allow the good bacteria and wild yeasts present in the grain to do their work without external interference.
It is a myth that using a very ancient starter is better than starting from fresh. A one-month-old starter will be very similar in character to a much older one. The main difference between any two starters will be the strains of wild yeast and bacteria present. Bread made with a hundred-year-old starter will perform and taste the same as bread made with a one-month-old starter, if they have the same feed schedule, using the same flour. But a starter made in San Francisco can never be the same as a starter made in Melbourne. The differences in the flours and environment mean that they will each contain different strains of bacteria, in effect giving bread a sense of ‘terroir’.
What matters is not the amount of time the starter lasts, but how well it’s taken care of. A newer starter, if properly established, will produce similar results to an older one that’s been well maintained. A newer one that’s been well maintained will produce better bread than an old one that’s been poorly maintained.
Below, I have outlined the process for establishing your starter from scratch, and have made some notes about some of the smells you may notice as the starter gets going. These are useful to have as a guide, but are not key to describing the healthy development of a ‘good’ starter. You may notice ‘off’ smells, but don’t worry. This can occur if the temperature is too low, and as you continue your feeding schedule the bacteria and yeast present will eventually balance out into a nice, healthy starter. You may find it simpler just to focus on the appearance, and get familiar with the fermentation process before trying to read too much into the characteristics of your starter.