The term “sourdough” can be off putting for some people and for this reason bakers may instead refer to the “wild yeasts” that are used in a sourdough leaven. What might be equally off-putting is that the wild yeast most often found in sourdoughs is Candida milleri. Off-putting because the Candida genus is most often associated with is C. albicans, which can cause irritation of the gut for some people. Rather than the yeast, it is the lactobacilli – the “good bacteria” so frequently heralded by producers of yoghurt or pro-biotic drinks, that provide the benefits of using a sourdough starter (described in my Bread Update article). These lactobactilli will happily co-exist with Candida milleri. However, there seems to be little agreement amongst bakers about the changes that might occur in the prevalent strains of yeast in the presence on these lactobactilli. Some say that whatever yeasts are initially used to seed your sourdough starter, Candida milleri will eventually dominate. Others think that the initial strain of yeast will simply mulitiply. We are beginning to exhaust my understanding of the science behind sourdoughs by now and, I fear, may also be in danger of exhausting your patience to read on, so I am now going to talk of my personal experience of making a natural leaven and forget the science.
Wild yeasts exist all around us, especially on foods such as grapes or potatoes, so the first step in using them is to capture them in sufficient quantity to leaven bread. This is easier said than done! For a hilarious, but “oh, so true” account of the process, I recommend you read the first chapter of Jeffrey Steingarten’s excellent book The Man Who Ate Everything. I have tried several different recipes for producing a wild yeast starter, and of these I found potatoes to be the most successful vehicle. The River Café Cookbook Two (the yellow book) contains a good recipe for a potato sourdough starter. I used this starter successfully for a couple of years, then went on a lengthy holiday, after which it appeared that my starter had died, and I had a couple of less successful attempts at recreating it. What I didn’t know then was that starters rarely die, although many of the yeast cells do, and they will lie unappetisingly as a liquid grey sludge. However, if you discard this liquidy part and recommence feeding the starter on a daily basis, you should be able to revive it rather than have to start again completely from scratch. Of course, real enthusiasts either take their starter with them on holiday or leave it in the care of a reliable friend!
After a couple of unsuccessful attempts at creating a new starter from potatoes, I recalled how housewives used to keep yeast going by keeping a portion of each day’s dough back to start the next day’s baking. The starter they purchased may well have been the compressed yeast we known today or, prior to that, brewer’s yeast. Either way it was too expensive and/or inconvenient to obtain it fresh everyday but the yeast cells would continue to multiply as long as they had a regular form of starch sugar to feed upon.
So that is exactly what I tried next. I made a batch of bread using the sponge and dough method (which contains a minimal quantity of baker’s yeast), kept a third of the dough in the fridge overnight, and then used that to bake again the next day. Progressively the starter smelt more sour and the bread took longer to rise. The pleasantly sour aroma indicated the presence of lactobactilli and, I believe, the increased fermentation time was due to wild yeasts dominating the initial baker’s yeast.
Of course, this method did need me to bake every day for a while until the starter was strong and stable, but at least you have something to see for all the work you are doing, unlike an unsuccessful attempt to create a fresh starter.
A variation on this approach is to build your starter using the wild yeasts that exist in the flour itself. This is more successful using wholegrain flours – either wheat or rye.
Rye bread is made in a quite different way to wheat bread, because of the difference in the type of gluten it contains. Britain of course has a cultural heritage of using wheat, whilst rye is the norm in eastern Europe. Whilst you can use either grain, or indeed a mixture of both, I do find that a proportion of rye in my starter helps the fermentation, so although the grain I use for my final bread is entirely wheat, it does contain a small proportion of rye, giving it a slightly grey colour.
Here are the steps in maintaining and baking with your sourdough starter.
Step 1 – Feeding
180g old dough
60g white flour
50 ml warm water
Mix to a dough and leave in a warm place for at least 4 hours or up to 24.
Step 2 – Refreshing the starter before baking
225g flour (75% white, 25% rye)
125 ml warm water
Mix to a dough and leave in a warm place for 4 hours.
Step 3 – Making the dough
340g refreshed starter (the rest becomes your new starter)
400g stoneground flour (white or wholemeal or a mixture of both)
260 ml water
Proceed as for the “sponge and dough” method from here.
To avoid the chemical used to treat tap water killing the delicate wild yeasts, I prefer to use pure spring water. You might want to substitute tap water for the final step, when the quantity is greatest but the yeast is at its strongest.
I leave the mixed flour and water for at least 10 minutes before adding the refreshed starter, and then wait another 10 minutes before kneading in the salt. These short resting periods help the gluten molecules to line themselves up, reducing the amount of time spent kneading.
Consider the water quantity above as a guideline only. Flours vary in the amount of water they can absorb, but you are aiming for a firm paste similar to the texture of a pastry dough, at least for the starter. Add as much water as you can handle when making the final dough.
Salt, whilst considered an essential flavour enhancer, does have a detrimental effect on the development of gluten, which is why I give the gluten some time to develop before it is added. However, care needs to be taken to ensure it is evenly distributed throughout the dough. Alternatively it can be dissolved in the water at the start of Stage 3. I use Malden Salt but grind it finely in a pestle and mortar before using.
Having made the dough I usually let it rise at a cool temperature overnight before shaping the loaves and proving in the airing cupboard for 2 hours. If the airing cupboard is also used for the initial rising allow about 5 hours.
I keep my starter in a large Kilner jar in the fridge. I have never found the fermentation to be so vigorous that the jar is in danger of exploding. This could be because I use only a small proportion of rye flour and the jar is never more than half full after adding a feed. The fact that the starter is also very firm may also have some bearing. If you prefer to make your starter entirely with rye it may be safer to store it in a plastic container.
©Suzanne Wynn 2011