The Chorleywood bread process (CBP) is a process of making dough in bread production. The process was developed in 1961 by the British Baking Industries Research Association based at Chorleywood, and in 2009 was used to make 80% of the UK's bread. Compared to the older bulk fermentation process, the CBP is able to use lower protein wheat, and produces bread in a shorter time.
CBP is able to use lower-protein wheat because some protein is lost during bulk fermentation of traditional bread; this does not occur to the same degree in mechanically developed doughs.
The process had an important impact in the United Kingdom, as at the time, few domestic wheat varieties were of sufficient quality to make high quality bread products, and it therefore permitted a much greater proportion of lower-protein domestic wheat to be used in the grist.
The Chorleywood bread process allows the use of lower-protein wheats and reduces processing time, the system being able to produce a loaf of bread from flour to sliced and packaged form in about three-and-a-half hours. This is achieved through the addition of ascorbic acid (Vitamin C), fat, yeast, and intense mechanical working by high-speed mixers. The last requirement means that it is difficult to reproduce CBP in a small-scale kitchen.
The CBP is only a method of producing quick-ripened bread dough. Large-scale bread-making with automated processes pre-dates the CBP by at least a century.
Flour, water, yeast, salt, fat, and, where used, minor ingredients common to many bread-making techniques such as Vitamin C, emulsifiers and enzymes are mechanically mixed for about three minutes.
The high-shear mixing generates high temperatures in the dough, which is cooled in some advanced mixers using a cooling jacket. Chilled water or ice may also be used to counteract the temperature rise during high-speed mixing. Air pressure in the mixer headspace can be controlled to keep gas bubbles at the desired size and number. Typical operating regimes are pressure followed by vacuum, and atmospheric followed by vacuum. The pressure control during mixing affects the fineness of crumb texture in the finished bread.