Making the Starter

On starters

(of course, if you already have a successful starter, skip this section)

What we need for our sourdough, is to catch some natural, and thankfully, air-born bacteria and yeast to act as our leavening agent.* This is different to normal (commercial) yeast bacteria (e.g. 'Lowan' brand, 'dry yeast'). Whereas commercial yeast consumes added sugar (and a little of the flour), operates in low acidity mixtures, and has been selected to leaven bread very quickly (e.g. on the order of 1-2hrs), the natural bacteria/yeast combination we are after actually consumes the flour only (no added sugar required!). A bi-product of this different reaction is lactic acid (amongst other things), which gives the dough its distinctive sour flavour and advantageously preserves the bread for many days against aerobic bacteria that would make it go stale. Many commercial flours are bleached and ground in such a way that natural bacterias are killed. For this reason, when making our initial starter, it is wise to use some organic (unbleached) flour (although not mandatory, I have gained a fine starter from plain 'Savings' brand flour).

Once cultivated, the bacteria-rich starter (as it is known), can be used to leaven our full loaf (obviously we'll need to add some more flour for it to eat). Initially, we'll have a lot of starter, and therefore use only a little of this original mixture. However, as this is depleted, we'll have to regenerate our starter. We don't need to go through the process described below, rather, use a smaller amount of the starter to leaven a loaf, and when your starter is sufficiently depleted, add some more flour and water as described below.

Starter will keep in the bottom of a fridge for many weeks (months actually, though most books will not advise this .. see note below on 'waking' a very old starter). It will need the occassional 'feed' of flour and water, but this is all. Starter is best stored at thick semi-liquid consistency (100b% is perfect) so that air-bubbles that evolve are able to escape the mixture. The alternative is a slowly growing time-bomb.

Starter can also be transported (even overseas if need be) by drying the starter out completely. This is achieved by letting the starter naturally 'dry' out on the bench, but better would be to add more flour until a very hard dough is formed.

* Actually, I read a recent study of where the starter bacteria and yeast originate from. Apparently, the most likely source is the baker .. !

Side note: waking a very old starter

It is possible, though not generally advisable, to wake up a starter that has been neglected for a few months in the bottom of the fridge. On first inspection, it will likely smell something like a paint tin and look little better than drain water. A black-grey liquid will have formed on the top and a very runny, soupy white flour mixture will have formed a lower fraction.

What to do?

Give the mixture a stir -- it will yield very easily to regaining its mixture. Throw away all but a teaspoon of the sickly stuff. Add your teaspoon to a fresh small bowl and add 100g water and 100g fresh (organic, unbleached if possible) flour. Sit on the bench top with a plastic film covering the bowl.
Come back after 24 hours. Hopefully it should be showing some signs of life. These could be surface mumps indicating that some CO2 is being evolved, or perhaps a stir will give a slightly stretchy, airy texture. Or perhaps not... Throw away most of it, leaving a table-spoon this time, and add 100g water, and 100g flour.
Come back after another 24 hours. Any improvement? Do this process a couple more times if needs be. Once it has attained a good aerated texture, and is not at all on the nose (i.e. no longer smells like paint stripper) then you are safe.
Add 200g water and 200g flour to a final 50g take of the active starter and you are in business.

Making a starter from scratch

Ingredients

200g organic flour
300g tap water

Method

Add flour and water to a small mixing bowl, mix to rid of lumps, to form a thick but smoothly flowing mixture. (It should be the consistency of thick pancake mixture. Add more water if in doubt.)
Leave, uncovered for 1 day, then cover with a piece of glad-wrap, putting a small hole in the middle of the wrap with a fork or skewer.
Leave on a bench for 3-4 days, adding a little more flour (plain) and water each day. The mixture will start to smell, eventually having a pungent yeasty oder. Grey-blue bacterial growths may appear on the surface. The whole mixture will have a grey pall. A clear liquid may form on top. Always mix it all together, with added flour and water to return mixture to original consistency.
By the end of 4 days, the mixture will be full of leavening agent and thus have a strong odour. Store in the base of a fridge as described above.

To use the starter on a regular basis, as will be seen below, it will be very useful to know the approximate percentage composition of the stater (in terms of flour and water). To do this, take a small amount (a table-spoon will suffice) of the 'rich' starter together with 100g of flour and 100g of water and allow to stand at room temperature for a day. This will give you a rich stater base with a known flour/water content for further use (100b%).

When making up starter amounts therafter, follow the simple rule of 1:1 water:flour. This is the assumed ratio for the recipes given below.