Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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chestnut

The wood of the European chestnut (Castanea sativa) and the American chestnut (C. dentata), from which tannin is extracted. Chestnut tannin extract was used extensively in France and other European countries, as well as in the United States, in the latter part of the 19th century and early 20th century. In the United States its use has declined sharply since the introduction of the Oriental chestnut blight (Endothia parasitica), which has virtually destroyed the American chestnut. Today Italy is the largest producer of chestnut wood extract for tanning.

The bark of the chestnut is not used because it imparts a dark color to the tannin, and its high sugar content would result in a higher percentage of soluble non-tans in the extract. The usual tannin content of the southern European chestnut is 10 to 13%, or higher, which is considerably higher than that obtained from trees in northern climates. The wood does not seem to reach its highest tannin content until the trees are at least 30 years old.

Chestnut extract tans rapidly and produces a firm leather. If used alone, however, it may impart a reddish color to the leather that is not desirable; therefore, it is used in combination with quebracho, mimosa, myrabolans, and valonia.

Chestnut is one of the pyrogallol class of tannins, and has a naturally low pH value. It also has a relatively low salts content and a high acids content. See also: VEGETABLE TANNINS . (175 , 306 , 363 )




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