It's just after sunrise in the yeasty warmth of The Earth's Crust bakery, and Tom van Rooyen is pulling 25 sourdough loaves out of the ovens. The loaves have been quietly rising all night, before being baked for about 35 minutes, and now their distinctive, slightly sharp aroma - freshly baked bread, just out of the oven - is wafting into my nostrils.
Sourdough bread is never cheap - it takes too long, demands specialised skills to make - but once you try it, you may get hooked. Baked in rough-looking globes, unlike the neat rectangles of factory made bread, it has a chewiness, a flavour, a satisfying depth to it that Mother's Pride or Wonder Bread couldn't begin to compete with. Toasted, it is comfort food in abundance. And even stale - which doesn't happen quickly - it's still good to eat. What's more, there is growing evidence to suggest that for people suffering from gluten sensitivity, proper sourdough bread may be more digestible than our square factory loaves.
I'm a devoted, if slightly hit-and-miss baker myself, but I've never had the courage to try sourdough. But later on, back in my own kitchen, I determinedly arm myself with Dove's Farm wholemeal rye flour, new scales, and an oven thermometer. I'm determined to learn how to bake this wonderful bread for myself.
Origins and symbolism
But just what is sourdough? Is this the original risen loaf? We shall never know exactly. What we can say is that for several thousands of years after the first farmers planted the first fields of grain - the einkorn and the emmer. These grains were eaten crushed and mixed with water into a simple porridge, or else baked as flatbread on a hot stone.
And then some baker, somewhere, around 6,000 years ago, noticed that the flour and water mix he'd left lying around forgotten was doing something odd. It was bubbling, fermenting; it was expanding; it looked off. It smelt a bit funny. He stuck it in the oven nonetheless - waste not, want not - and became the first human being to sniff that wonderful aroma: the smell of baking bread. The taste and texture were different too: his bread was chewier, it had a more interesting flavour. Perhaps he began experimenting himself; maybe he told other bakers. But however it happened, the new baking technique caught on, was developed, and gradually spread all around Europe and the Middle East.
This is the process known today as sourdough, in which a "starter" of combined flour and water is fermented over several days with regular additions of flour and water by the wild yeasts and lactobacilli naturally present in ground grain: this starter is then added to the baker's dough, which is left to rise for several hours, and produces delicious bread full of holes, with a firm springy crust. The secret of this transformation? Gluten, a protein found in all forms of wheat, rye and barley.
So satisfying was the new-style bread that over millennia it gradually took on quasi-religious status, a metaphor for nourishment, for harvest, for money, for life itself. Bread-making became an intrinsic part of village or small-town life, just as a wind- or watermill was a part of the local landscape. The farmer took his grain to the miller, who supplied the baker, who made the bread. Once the bread was baked, his big ovens were open for common use - a tradition that persists to this day in rural communities: I've eaten Christmas dinner in Spain, where the turkey was roasted in the local panaderia oven. Over the years other forms of yeast came into use as the basis for different styles of bread.
Mass production problem
But by the 20th century, the writing was on the wall for the local miller and baker. Reliable readymade yeast was now available for large-scale commercial baking, and the new roller mills, processing tons of grain at high speed, concentrated the processing of wheat in big central factories, sending thousands of small millers out of business. In 1961, scientists at the Chorleywood Flour Milling and Bakery Research Association Laboratories in Hertfordshire developed a new industrial process for the speedy mass production of bread, to complete the degradation of British bread. In the huge factories using it, bread could now be churned out in just three and a half hours flat, from flour to wrapped loaf, the long fermentation process cut to the bare minimum, to produce soft pappy bread with almost indefinite shelf-life. "I've kept a loaf of wrapped sliced bread for three months without it losing its squishy texture, or going mouldy," Andrew Whitley told me. "That's a defiance of nature: it's an abuse of language to call it freshness."
In order to produce an acceptable loaf in the minimum of time, a whole arsenal of additives is necessary: among them extra yeast, extra gluten, fat to improve crumb softness, reducing agents to help create stretchier doughs, soya flour to add volume and softness, emulsifiers to produce bigger, softer loaves and retard staling, preservatives - to extend shelf-life, and any of a wide variety of enzymes, legally defined as "processing aids" which do not have to be declared on the label. As a 1974 Technological Assessment Consumerism Centre report put it: "British bread is now the most chemically treated in western Europe."
The giant bread-making businesses plant a weighty carbon footprint on the earth, with their networks of industrial plants, depots and long-distance haulage; compare this, suggests Joanna Blythman in her book What to Eat, with a local bakery supplying its local area, often using flour milled in a local mill.
To our shame, we have now exported the Chorleywood process all over the world. Baking guru Julia Child remarked memorably "How can a nation be called great if its bread tastes like kleenex?"
What is the impact on our health of bread produced in this way? As an epidemic of diabetes sweeps the west, gluten sensitivity also appears to be on the rise. There are no reliable statistics for gluten sensititivity, but one estimate put it as high as 18 million people in the US alone. And the figure is certainly rising, if the current boom in gluten-free everything is anything to go by.
Moreover, the incidence of coeliac disease - the most extreme form of reaction to gluten - has been surging over the last few decades. In a 2009 study published in the journal Gastroenterology, researchers studied the blood of 10,000 people from 50 years ago to that of 10,000 now: they found that the markers for full-blown coeliac disease had increased by 400% in that time. A conservative estimate suggest that one in 100 of us has the disease. And hundreds, thousands, probably millions more are gluten-sensitive to the point where it is giving them serious health problems: the exploding figures for IBS, for Crohns, for every variety of digestive woe, too, are suggestive.
Is it significant that factory-made bread has extra gluten added, and the western diet today is awash with gluten-containing wheat? When my youngest daughter was being tested at Great Ormond Street Hospital for possible coeliac disease, the doctors handed me an enormous list of wheat-containing products to be strictly avoided - not just the obvious breakfast cereals, sandwiches, cakes, biscuits, pasta and pizza, but rye crackers. sausages, soya sauce, bouillon cubes, modified food starch (present in many baby foods), some made-up soups and sauces, and the TVP (textured vegetable protein) beloved of vegetarians.
Hardly surprisingly, there's a growing school of opinion today that considers all grains toxic to human physiology, responsible for a whole slew of maladies from coeliac disease through autism, diabetes and cancer to Alzheimer's. Moreover 10,000 years, they say, isn't nearly long enough for humans to have adapted to gluten.
But like many others I find it hard to believe that the most important food in all our recorded history, so highly revered, and so widely eaten, could have been quietly poisoning us all the time. Is it not rather the staggering amounts of unfermented gluten people are now consuming, unmodified by the long fermentation process of traditional bread making, that are responsible?
Sourdough health solution
And what's beyond doubt is that when people switch from supermarket to sourdough bread, they're often delighted to find they can eat it without bloated belly discomfort. "We get people coming in who say 'we can eat your bread without any problem unlike ordinary bread which just blows us up'", says Alastair Ferguson, of Brighton's Real Patisserie, who sells his own sourdough all over the city.
In the long slow fermentation that produces sourdough bread, important nutrients such as iron, zinc and magnesium, antioxidants, folic acid and other B vitamins become easier for our bodies to absorb. Diabetics should note that sourdough produces a lower surge in blood sugar than any other bread: in a 2008 study published in Acta Diabetologica, subjects with impaired glucose tolerance were fed either sourdough or ordinary bread: the sourdough bread produced a significantly lower glucose and insulin response. In the sourdough process, moreover, gluten is broken down and rendered virtually harmless. In one small Italian study, published in the journal Clinical Gastroenterology and Hepatology, in January 2011, coeliac patients fed sourdough bread for 60 days had no clinical complaints, and their biopsies showed no changes in the intestinal lining.
Nutrition therapist and yoga teacher Lisa Christie, 36, was instructed to go gluten-free for 30 days during the first session of her nutrition training course. "It was a revelation. I realised I'd always had low-level pain in my stomach and further down: it just stopped. And it was as if a veil had been lifted - my perceptions sharpened, and I had more energy. I'd always struggled to keep weight right too; - when I stopped gluten I started absorbing food properly again, and quickly reached a normal weight."
"I was still eating bread on and off, but then I was going camping with some friends, so I bought a big loaf of rye sourdough, and found that I could actually eat it with no ill effects. I found it a bit vinegary and odd at first, but pretty soon I developed a taste for it, and now I eat it all the time - I make my own from Dove's Farm Organic Kamut flour.
"Gluten sensitivity is one of the most common problems I see in my practice. Ditching commercial breads is a great step for anyone to improve health and wellbeing, and for many of my patients, restricting their gluten intake to properly-made sourdough bread - wholegrain wheat, rye, emmer or kamut - works really well."
Meanwhile the sales of sliced wrapped bread are slipping by the day - in 2012 we bought 31m fewer packets of them - and is it a coincidence that 32% of the bread bought in the UK is binned? Meanwhile the growing popularity of the famous Poilane pain au levain, on sale in upmarket stores, and the French chains of shops, Paul and Le Pain Quotidien are bringing sourdough to more and more new markets.
The return of artisan bakers
And while the supermarket bosses gloomily study dropping sales, the number of small artisan bakers cropping up around the country is growing slowly but steadily. "In 1976 I was going against the tide of history" says Andrew Whitley, the Cumberland baker who co-founded the Real Bread Campaign in 1990, "baking bread that took hours and hours in a wood-fired oven. It was assumed, at the time, that all small bakers were going out of business. Now proper bakery businesses are cropping up all over the country". He welcomes the huge and growing demand for sourdough: "I don't believe it's one of those passing foodie crazes, like pomegranate seeds or burrata, the new upmarket mozzarella. I think lots of people will try it out because it's the new thing, then they fall in love with its flavour and texture, and they find it much more digestible, much kinder to their stomachs."
Where I live - admittedly in the affluent south-east - I can buy properly-made sourdough bread at eight different shops within 10 minutes' walk, three of them small artisan bakers which have opened within the last six weeks. Sourdough bakeries are springing up all over the country. One such is The Earth's Crust, just three years old, launched by Tom van Rooyen and his wife Pavlina, from a garage in Laurieston, near Castle Douglas in south-west Scotland. "I'd been in catering, all sorts of jobs," Tom told me, "but I've had a passion for bread for years, and we decided to take the plunge. We've started very small, just the two of us, operating from our garage, and we've never had our own shop: we sell at farmer's markets, agricultural shows, and now we run breadmaking courses too which are very popular. We do three regular monthly farmer's markets, local events, and we've built up a solid clientele of regulars. Since they only see us once a month, lots of our clients buy 10, 12 loaves at a time, and stash them in the freezer: sourdough bread freezes really well."
And with the rise of good bread also comes, hearteningly, the rise of the community bakery, returning bread to its old role at the heart of village life. In October 2008 Dan McTiernan and his wife Johanna launched The Handmade Bakery in Slaithwaite, in West Yorkshire, using the stone-bottomed pizza oven of a nearby Italian restaurant during off-hours, and making 12 loaves a day. Lacking the funds to equip their own bakery, they created a not-for-profit cooperative, the first subscription bread service in Britain, supported by subscription. Members commit to a loaf of bread a week, the bakery produces 1,500 loaves a day, and its adjoining cafe is a cheerful hub of local life, running regular courses in breadmaking. This pioneering venture has been widely copied.
Supermarkets, meanwhile, are fighting back with their own "sourdough" in their inshore bakeries: it may look delicious - but it is likely to be ordinary bread to which as dash of dried powdered sourdough starter has been added. Amazingly, there is no legal definition of sourdough bread.
But one way or another, sourdough's future seems secure. Fancy trying your hand at making it? The artisan baker Bakery Bits, for example, supplies all the stuff you need: master-baker Richard Bertinet has produced two magnificent books, Crust and Dough, which both come with explanatory DVDs; try, too, the excellent River Cottage Handbook no 3 Bread by Daniel Stevens, or Andrew Whitley's own excellent Do/Sourdough.
Sourdough breadmaking is a long slow learning curve ... I'm still trying to work out why my first attempt turned out with a brick-hard orange crust and a soggy claggy crumb. Any suggestions, all you bakers out there?
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French style rye sourdough on a bread stall at Borough Market in London.