Sourdough Bread
Bread Basics
Leavened bread is known to have been baked perhaps as early as 4000 years ago, by the ancient Egyptians. It's more basic counterpart, unleavened bread, stretches back far further, beyond history. It is not known how the Egyptians discovered methods of rising their bread, but we know they were also brewers, and the use of yeast could have easily been transferred to breads, either deliberately or accidentally. Bread has been a dietary staple across innumerable cultures ever since, being a lasting, portable and (until fairly recently) healthy food type.
When the microscope was developed in the nineteenth century the leavening agent, a single celled fungi named yeast, was discovered and soon began to be produced commercially. With economic pressures, commercial yeasts were bred for speed, stability and lack of strong flavor. Also, another bacteria, lactobacillus, which lives in symbiosis with yeast, was not included in commercial developments of yeast as it was technically unnecessary, despite being present in all prior leavened breads. Combined with ever more refined flours, and the addition of all sorts of fats, oils and sugars, bread continually progressed (or regressed) toward the bland, white, sweet enclosure for sandwiches for know today, which coincidentally happens to be edible. This cheap impostor foodstuff has made baking at home redundant for most people.
Mercifully, one can still bake bread in the healthy tradition, though it now sadly, and ironically, takes more effort than relying upon industrial processes. Baking one's own is nutritionally superior, develops simple but important skills and lowers reliance upon industrial society (if only a tiny bit), tastes fantastic, and cultivates patience. It also makes the kitchen smell fantastic. For these simple reasons it's a rewarding practice.
Knowing the basic processes of leavening can be of aid for the would-be baker. Yeast is a single celled organism that feeds on carbohydrates and excretes carbon dioxide and alcohol. The carbon dioxide is what fluffs up the bread, whilst the alcohol evaporates in a bread-making situation (in a brewing situation it remains and the carbon dioxide escapes). Lactobacillus feeds on by-products of yeast fermentation and excretes lactic acid, which causes the environment to sour. This discourages other microbes from developing, which protects the bread from spoiling. Both organisms are capable of speedy reproduction and are very difficult to kill. The only way to kill off a population is to raise the temperature of their environment to over about 38 degrees Centigrade (100 degrees Fahrenheit). Both organisms are encouraged by sugars and starches, such as potatoes, flours, sultanas or grapes, and are discouraged by salts, fats and oils. A final important component of bread is gluten, which is found in the protein of flour. Gluten is what gives the dough its elastic structure, ensuring the crumb of the risen dough will hold itself together, instead of crumbling like a cake or cookie. Gluten is developed in dough by kneading it thoroughly. Knowing these basics can greatly help you trouble shoot quality issues with your bread making.
Sourdough Starter
Sourdough bread making doesn't rely upon commercially produced baker's yeast, but cultivates organisms predominantly already present in the flour (though some maintain that it's caught from the air). It is thus the least reliant upon the crutch of industry. It is however, a more involved process than normal baking, but with heightened rewards. It is recommended that the would-be baker begin with normal bread making to get adept at the other tasks of baking before trying sourdough, but nevertheless, if you're keen to cultivate some free yeast just for the hell of it, by all means have a go.
To begin cultivating a population of yeast and lactobacillus combine equal parts (preferably by weight) flour and water, perhaps 20g each, in a jar, put the lid on to discourage any other life forms and leave it in a warm place (about 70-85 degrees Fahrenheit, if room temperature is far from this, try an idling oven) for 48 hours. Check it after 24 to see if any bubbles are visible on the sides of the jar. If bubbles have formed, you're in business. If none have formed after about 48 hours, discard the slush (though none of your confidence) and begin again. When you've got a visible set of bubbles around your jar, you need to feed your starter. Discard half of it (or even more, there's enough bacteria in a few mL), and to the remainder add equal parts water and flour. Leave again and observe to see if it's frothing up again, and smell it each time also. It should smell sour, and different to its initial smell (i.e. flour and water) and not rotten. The culture will typically not be very stable for at least a number of feedings like this, so don't be in any kind of hurry.
The culture will have a cycle that you will slowly get to know if you persist with maintaining it. As it gets to the stage where almost all of its food is eaten, population growth will slow, and there'll be much waste product in your starter. The smell typically won't be particularly nice, and there may be a layer of brown liquid, called hooch, atop your starter. This is the late stage which you want to avoid. Before your starter reaches this point, you want to have divided and replenished it with fresh food. That said, the culture can still improve from such a state. Remove the hooch, keep a small amount of the starter and feed it normally.
To get a starter ready for baking, aim to rise the starter twice to the point where it expands so much that it collapses of its own accord. If it's nearing the top of the jar, stir it a little so it reduces in volume (but don't count that as a collapse). Once you've done this, you can refrigerate the jar, which reduces yeast activity and means you don't have to feed it so often. Keep it away from the hooch stage though, by checking on it and feeding it once every one or two weeks as necessary.
Rye flour is regarded as the best flour to use for starters; and it tastes great too.
Baking
Baking sourdough takes longer than normal bread that relies on industrial yeast, but if you're a good person, you'll know that in spite of the modern axiom ‘time is money', you'd rather more of the former than the latter. What you want to do when preparing a sponge from your starter is mimic the process of feeding a starter, but to increase the volume with each feeding until you have a sponge of about 100% hydration (which is achieve by adding equal portions by weight of flour and water each time) containing about 40% of the total volume you aim to have for your loaf.
Firstly you need to activate your starter, so take it out of the fridge about 2-3 hours before you want to begin, and let it warm up. Then take with 20g starter, and add 20g flour and water each. This should give you 60g sponge after a 3 or so hours fermenting. Then add to this 60g flour and water each, which after another fermenting spurt, should yield 180g sponge. I find that this is enough for a 500g gram loaf of sourdough, though more may be better. Mix the 180g active (it should be very bubbly) sponge with your other chosen baking ingredients. For me this means: a small addition of rye flour, some white flour, more water, 2 tsp of salt and perhaps 50g butter or 60mL olive oil. It is possible to actually make great sourdough from merely flour and water though. The amount of water and flour required are relative to each other. For a normal loaf, 500g flour will require about 300mL water. But with sourdough you need to factor in the water and flour contained in your sponge. I find that it can be easier, particularly if you already have baking experience, to just add your flour up to the desired amount and carefully add water as necessary. For caution's sake, I tend to over water (but only by a tiny amount), as the flour will take up the moisture more as you knead it, particularly if you've got any wholemeal flours in the dough. Next, knead the dough very thoroughly: you should be able to observe the dough becoming more homogenous and elastic as you knead. It should take at least 6 minutes, but if in doubt, keep kneading, it can't hurt.
Leave the dough to ferment for about 7-8 hours (again use an idle oven for warmth), knocking the dough back, re-kneading and shaping it about halfway through. The dough should double in size with the fermentation process, if it doesn't, the starter may need to be worked up to a more vigorous standard, or your dough may need to rest somewhere a little warmer, aim for about 28-32 Centigrade (around 80-90 degrees Fahrenheit). When sufficiently risen, place in a very hot oven (about 250 degrees Centigrade, or 480 degrees Fahrenheit) for 15 minutes. Lower temperature to 200-220 degrees Centigrade (400-425 degrees Fahrenheit) and bake for a further 15 mins. If the loaf appears to be burning at all, lower the temperature a little further.
To ensure that it's cooked, after removing it from the oven, gently tap the bottom of the loaf: if it sounds hollow, you're in business. Turn out onto a wire rack, and don't eat it before it's well cooled. - Fieldmouse
exponentiation ezine: issue [3.0:culture]
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