[147] Waugh, F. A. Vt. Sta. Bul. 53:51. 1896.
[148] Goff, E. S. Wis. Sta. An. Rpt. 18:302. 1901.
[149] Waugh, F. A. Plum Cult. 297-300. 1901.
[150] Hansen, N. E. S. D. Sta. Bul. 93:67. 1905.
[151] Carrière, E. A. Prunier Saint Julien. Revue Horticole 438-439. 1892.
[152] Waugh Plum Cult. 247. 1901.
[153] Hansen, N. E. S. D. Sta. Bul. 87. 1904. Ibid. 93:68. 1905.
[154] Wickson, E. J. California Fruits 348. 1891.
[155] A prune is a dried plum. The requisite for a prune-making plum is that it have a large proportion of solids, particularly sugar. Comparatively few varieties of plums bear sufficient amounts of solids so that they may be successfully cured into a firm, long-keeping product. Only varieties of the Domesticas are used in making prunes, though possibly some of the Insititias might be so used. Prunes are chiefly used in cookery though some of the finer grades from France are sold as confections.
Prunes are either dried in the sun as in California; partially cooked in ovens and the curing completed indoors, as in European countries; or wholly dried in evaporators, as in the Pacific Northwest. Sun-drying is the most economical method where the climate permits. The half cooking does not make so attractive a product but when skillfully done the prunes are possibly more palatable, as the cooked flavor is liked by consumers. Beyond question the best prunes are made, however, all things considered, in well-managed evaporators. In evaporators the changes of curing take place most perfectly and uniformly so that, as a rule, the prune looks better, keeps longer, is not so tough and has a more natural taste of the green fruit.