The sourdough starter is basically a fermenting dough or batter. Sourdough breads have a slower fermentation and a characteristic sour flavour due to the production of lactic acid by lactobacilli (the same bacteria in yoghurt) which colonise the starter alongside the yeasts.
It is quite simple to make a sourdough starter and once you have started you may become quite possessive of it. I know of starters that are over 20 years old and the one I use is nearly 2 years old.
Yeast requires 3 major factors to replicate; sugar, warmth and moisture. If we can provide these we can produce a starter.
Mix a cupful of flour, preferably wholemeal, with a cupful of warm water in a suitably large container to allow plenty of frothing. Ideally it should be at least four times the volume of your original batter. Whisk the flour and water to incorporate as much air (and thus yeast) as possible. Place in a warm place and leave to ferment. The starter may take several days to start fermenting so check it every 12 hours or so. When you see the first bubbles of fermentation you are ready to feed the starter.
Stage 2 The first feeding
When you see evidence of fermentation you can give your starter its first feed.. Whisk in another cupful of flour and warm water, replace the lid and leave for another 24 hours. After a day or so you should see signs of vigorous fermentation and it will start to smell – the odour may be sweet, sour, vinegar-like, or like rotten apples or soured milk!
Stage 3 Subsequent feeding
Discard half of your starter and replace this with another cup of flour and water. I would also decant it into a more permanent container at this stage. Leave in a fairly cool place. For the first week I would repeat the above process every day i.e discard half the starter and replace with fresh flour and water. You may notice that the odour will develop into a rounder aroma as the starter progresses.
After a week of this daily feeding you should have a fairly vigorous starter that is now ready for use.
If you are going to use your starter regularly, it is best to keep it as a thick batter and to feed it daily. But if you bake less frequently, it would be better to slow the fermentation down by making it colder, drier or both.
If you keep your starter in the fridge you will only need to feed it weekly.
Or you could add more flour, enough to make a stiff dough, and feed it every 3-4 days. To feed a dough, discard half (or bake with it!), make a new flour and water dough and incorporate this into the remaining starter dough.
Alternatively you could do both; keep your starter as a dough in the fridge and you will only need to feed it every 2-3 weeks.
If you do keep it in the fridge, please remember to remove it from the fridge a day or two before you want to bake with it. This is to ensure that your starter is nice and active ready for baking.
For long-term storage you can freeze the dough for up to 3 months.
Now use your starter and bake up a delicious sourdough loaf. You will absolutely love it, trust me…