Sourdough is a culture of yeasts and beneficial bacteria that occur naturally in bread flour and dough. The yeasts are more varied and less concentrated than baker’s yeast, so they raise the dough more slowly. The lactic acid bacteria (LAB) also require many hours of fermentation to work their wonders.
Real sourdough is very simple, as befits a method that’s thousands of years old. You take some starter, refresh it with several times its own weight of fresh flour and water and let this ferment for some hours until the yeast population has grown. You use most of this dough to make bread by adding more flour, water and salt, and keep a little bit back as your starter for the next batch of bread.
(There is no need to fuss over and ‘feed’ your starter regularly: we’re talking fermentation here, not pet-care. Established starters will keep undisturbed in the fridge for days, weeks or months between bakes.)
Time is crucial. Whan the sourdough is allowed to ferment slowly over several hours, it is able to transform the main ingredient – flour – in ways that together justify sourdough bread’s claim to be the best.
That's a pretty compelling list of benefits even if we ignore the fact that bread-related metabolic complaints have proliferated just as the time taken to ferment most commercial bread has reduced. It’s this interplay of time and commercial advantage that should make us ask searching questions of some of the ‘sourdough’ breads now on offer.
Signs that your sourdough is real:
Since there is no legal definition of sourdough, despite the Real Bread Campaign's call for one, it is quite possible to give this name to a bread made with a dried sourdough powder or ‘pre-mix’ and raised quickly with baker’s yeast.
Such bread may be shaped in a winsome ‘boule’. It may even have a hint of flavour. But it’s unlikely to deliver on any of the benefits listed above unless lactic acid bacteria have fermented the dough for several hours. It’s even possible that ‘sourdough’ is being used as an opportunistic descriptor of ordinary bread in the hope of selling more, rather as the label ‘organic’ would be used by unscrupulous greengrocers in the days before that trade was properly regulated.
But the best way knowing that your sourdough is genuine is to make it yourself. And the really good news is that it’s easy to fit it into busy lives.
October 2014 saw the publication of a study, initiated by Andrew, of the effect of bread fermentation time on the gut bacteria of patients with Irritable Bowel Syndrome. This is the first part of a wider investigation into the under-researched issue of how breadmaking method affects digestibility and nutrient availability. Bread Matters plays an advisory role in this work, which will provide robust evidence for public-health-led innovation in milling and baking technologies.
The title of the article is
Effect of Breadmaking Process on In Vitro Gut Microbiota Parameters in Irritable Bowel Syndrome
The authors are Adele Costabile, Sara Santarelli, Sandrine P. Claus, Jeremy Sanderson, Barry N. Hudspith, Jonathan Brostoff, Jane L. Ward, Alison Lovegrove, Peter R. Shewry, Hannah E. Jones, Andrew M. Whitley and Glenn R. Gibson.
Read the Abstract or the full article here.
© Andrew Whitley 2013
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