What is a 'leaven' and why use one?

The bakery's leaven, or 'sourdough' culture, is a mixture of water and organic whole rye stoneground flour, providing an environment where naturally occurring yeasts and bacteria thrive. The leaven is kept alive, and healthy, through regular feeding with a consistent balance of additional flour and water. A healthy leaven not only provides the yeast to raise the bread but also additional benefits from the bacteria it contains.

The bacteria in the leaven culture are strains of lactobacilli which form a unique combination with natural yeasts found in the flour (originating from the coating of the grain). No two leavens are the same so flavours and properties of breads produced from different leavens will always be unique. The bacteria & yeast combination provides a subtle but satisfying taste and a special texture, giving the bread body, character, and a slightly chewy nature. The acidity of the leaven also helps the keeping quality of the bread by inhibiting the development of mould.

Why use a slow fermentation?

Allowing a large proportion of the bread flour to ferment over a long period (about 12 hours) supports chemical changes in the flour that ease the body's extraction of minerals such as iron, potassium, magnesium, and zinc from the resultant bread. All grains contain phytic acid which works to reduce the body's absorption of the important minerals the grain has to offer. Soaking grains, or flour, over time counteracts the phytic acid and so greatly improves the nutritional properties of the consumed bread.

Why use stoneground flour?

Stoneground flour is, as the name suggests, produced from whole grain being ground between two large horizontal stones. The upper stone rotates above the fixed lower stone. Grain is introduced through a hole in the centre of the upper stone and ridges in the stones work the grain to their outer edges milling it as it goes. Millers control the coarseness of the flour by adjusting the gap between the stones. The resultant flour is left as wholemeal or sieved to provide other grades, including white.

The difference between stoneground flour and modern roller milled flour is that the process does not completely strip out the wheat germ and bran from the grain. Even the sieved stoneground white flower contains fragments of bran and germ and it's these parts of the grain that contain the bulk of its proteins, minerals and vitamins. The lower operating temperature of the stone grinding process also has a less harsh effect on the components of the grain and their nutrients than occurs in roller milling. Although roller milled flour has aspects of the bran and germ put back into the end product, the stone grinding process offers a more natural approach to obtaining a complete nutritious ingredient for high quality bread.

Due to the contents of the white stoneground flour it is not white as is seen in mass produced flours. Stoneground white has an attractive creamy colour.