(Above: Yeast up close)
Sourdough bread is bread made with a natural yeast (also called a sourdough starter) that has been fermented by the baker, rather than fresh or dried yeast which comes from a packet. I found making my own starter scary at first - What if I killed my yeast? Or what if I poisoned someone by making the wrong yeast? What if my starter took on a life of its own and formed some kind of illegal drug ring in my kitchen whilst I was out at work during the day? Over the last 3 years, I've tried to pool all the information that Iíve learned about creating, keeping and maintaining a sourdough yeast culture for you to glean Ė here it is, I hope it helpsÖ
How to make a yeast starter
USE IF: You donít have a starter and want to make one from scratch
Day 1 - In a clean, sterilized tupperware mix equal parts water and flour. You can use whichever kind of flour you like, wholegrains like wholemeal and spelt tend to speed things up a little bit, but you can use anything. I suggest, for your first step, use 200 g flour and 200 g water. Yeast bacteria lives on the flour Ė the water acts to kick-start the organisms into life, and then once they are awake, they feed off the sugars on the flour. Once you have mixed the flour and water together so that it is combined, cover the tupperware and leave it in a dry, warm and dark place.
Day 2 - Keep an eye on your yeast, it should start to form bubbles and the smells that it emits will change, from floury, to cheesy to alcoholy or fruity. Smells depend on many variables, so often using different flours, different temperatures of water, different temperatures in your kitchen alters the smell.
Day 3 - Your yeast should have started to bubble, but donít worry if it hasnít yet, it may be that the flour you have used doesnít have very active little beasts in it. You are now going to give it a second feeding. Tip out half of the flour and water mixture down the sink. Then add in another 100 g of flour and a 100 g of water and mix well. Leave it out of the fridge once more, again keeping an eye out for smells and bubbles.
Day 5 - Give your starter another feeding, again by tipping out half of the mixture and adding in another 100 g flour and 100 g water.
Day 7 Ė Happy Birthday, your starter is a week old. Give it its fourth feeding in the same way by tipping out half and refeeding but this time, find it a home in the fridge.
Day 9 Ė Day 14
You will have started to notice changes, smells, bubbles and the fact youíre your yeast is growing, doubling in size with every feeding. Keep feeding it every other day and keep it in the fridge. After 2 weeks, you will have a lovely bubbly starter that is ready to use for sourdough.
How to feed your yeast starter
USE IF - If youíve been given someone elseís yeast starter, are feeding the one youíve made yourselves, your starter looks dead, you havenít fed your starter in a while.
1. Tip your yeast into a clean, sterilized tupperware. Add in equal parts water and flour and mix so that it is combined. Cover the tupperware, leave it in a dry, warm and dark place.
2. Leave your yeast for 2 days at room temperature, then on the 2nd day, tip out a third of your flour and water. You can use this tipped out mixture for making bread, give it to someone so that they can grow their own starter or just tip it down the sink. Add more flour and water, in equal parts and mix.
3. Once you have mixed your flour and water together, pop the starter back in the fridge. Depending on how often you make bread, feed it by tipping out a third and adding more flour and water to feed. For tips on how often to feed your starter, see belowÖ
How often do I feed my starter?
Your starter needs to be kept active for you to make a nice loaf of bread. The rule that I generally go by is that, if I want to make bread on Wednesday, I will feed it on the Monday before, so that the yeast has time to reactivate. However, this is only applicable for a starter that is being regularly fed, say once a week. If you havenít fed your starter in a while, go back to the guide about Ďhow to feed your yeast starterí and spend a week feeding it up before you use it for bread.
What if I donít feed it?
Remember Ė water wakes up the yeast that lives on the flour, the flour provides it with food. If you donít add in water and flour, it will starve then go to sleep. (But it wonít necessarily dieÖ)
Is it dead?
Probably not. Yeasts are tough cookies. If it looks dead (if it is mouldy, smells bad, grey etc. etc.), get rid of the nasty looking bits then try going back to the Ďhow to feed your yeast starterí recipe and feed it up for a week or so until it is bubbling and smells better.
Seriously though, I really donít want to feed it.
If you arenít going to make bread for ages or are going on holiday or really canít be bothered to spend your life caring for miniscule organisms in your fridge, donít worry. If we go by the priniciple that water wakes up the yeast and flour feeds it, then donít add so much water into your mixture, so that it is less active, but still has something to eat. Therefore, rather than creating a mixture made from equal parts flour and equal parts water, make a mixture that is two thirds flour and one third water Ė you will end up with quite a stiff, floury mixture instead of a gloopy one. The stiffer it is, the less you need to feed it.
What should it smell like?
Starter is a ferment, so it should smell similar to other fermented things like cheese, beer, wine, champagne. It can also smell quite floury at times or like fruit. If it smells like feet or death, donít bake with it. Instead, feed it until it smells acceptable again.
Whatís this brown goo?
Very often, you will end up with a thin layer of brown or grey liquid sitting on top of your starter. It looks terrifying but, essentially, itís hooch, or, pure alcohol that the yeast excretes. Yeast wee, basically. Donít drink it, don't panic, just tip it out and throw it away.
How much yeast starter do I need for a loaf of bread?
Recipes vary, but I generally use between 100 Ė 200 per cent yeast starter. For those not familiar with the bakerís percent, that means for every 1000 g of flour, I would use between 100 g and 200 g of yeast starter.
How long will my starter last for?
Sourdough starters can live for decades, some even say centuries. They are living things that change all the time. If you feed them and look after then properly, they will go on giving you bread for years to come, they might even end up becoming heirlooms!
*If you would like to learn more about making sourdough and using different yeasts, my ferment focussed bread-making classes are running until May 2017 in Leyton, London. Book here.*
Writing and images by Julia Georgallis
(Above: Yeast up close)