Old dough (pâte fermentée) may be made with yeast or sourdough cultures, and in essence consists of a piece of dough reserved from a previous batch, with more flour and water added to feed the remaining flora. Because this is a piece of old dough, it has the typical ingredient of salt to distinguish it from other pre-ferments. Once old dough had rested for an additional 10 hours of age, the French named it Levain de Chef. History The common, but undocumented, origin given for the term poolish is that it was first used by Polish bakers around 1840, hence its name, and as a method was brought to France in the beginning of the 1920s. "Poolish" however is an old English version of "Polish", whereas the term seems to be most used in France (where "polonais" is the word for "Polish"). Some nineteenth-century sources use the homophone "pouliche", a French word that typically means a filly. With either spelling, the term only appears in French sources towards the last part of the nineteenth century. There is not currently any credible explanation for the origin of the term. Use A ferment is easy to make and usually consists of a simple mixture of wheat flour, water, and a leavening agent (typically yeast). Two schools of thought exist regarding the inclusion of salt or sugar. They both act to inhibit or slow yeast growth, as determined by time to proof or rise, so they are not usually included and instead are added to the final dough. Ultimately, the amounts of each ingredient, and when they are added, depend on pre-ferment and final-dough formulas. In some countries (mainly Eastern Europe, Baltic and Nordic countries) rye flour is also used to make a starter. Traditional Finnish rye starter consists of only rye flour and water, no sugar or yeast. Some might also use yogurt to help hasten the starter to rise. A flour-to-water ratio of 1-to-1 results in a relatively fluid ferment. Stiffer doughs such as 2-to-1, may also be used. After mixing it is allowed to ferment for a period of time, and then is added to the final dough as a substitute for or in addition to more yeast. There are distinctly different brew types of pre-ferments designed for computer-controlled bakeries that use a rather different series of ingredients, including oxidizers, needed for continuous dough-production processes. Fermentation is sometimes performed in