http://www.angelfire.com/ma4/j_mayo/uscanteen.html
From a posting while searching this subject on the ACBB site some years ago by Kevin O'Beirne (in part):
"The cover is the most visible aspect of a Civil War canteen and, unfortunately, the vast majority of Federal reenactors' canteen covers are completely out-of-synch with period documentation. A typical Yankee reenactor has a canteen covered with dark blue kersey (wool) material—often of the same type of fabric as his uniform coat.
Many early canteen covers were satinette, which was a cheap cotton warp/woolen weft fabric that appeared to be "finished" only on one side. Once the Civil War began in earnest, the grade of material used for canteencovers actually declined. It is interesting to note that covers were not subject to Federal army inspectors, as was the canteen body and spout. The 1865 Quartermaster Department regulations, which codified what the army had been purchasing throughout the war, specified only that cover material should be, "a coarse cheap woolen, or woolen and cotton fabric". In contrast, the kersey wool material used on most reenactors' canteens is a "premium" fabric.
Material purchase records as well as relics from the period show that the vast majority—probably over three-quarters—of Federal canteens were covered with jean cloth, which was a very coarse, cheap cotton warp/woolen weft, twill woven material. Reproduction jean cloth-covered canteens can be ordered from various suppliers, and canteen cover kits are also available from many cloth vendors and makers of high-quality reproduction clothing.
On occasion, any cheap cloth that was available on the open market was employed by private firms and by government purchasing agents to meet deadlines on canteen delivery contracts. For example, a large number of canteens issued from the Schuylkill Depot between autumn, 1862 and summer, 1863 were covered with striped furniture upholstery fabric which, not surprisingly, proved to be very durable.
The predominant color of canteen covers issued by the Federal army, especially jean cloth covers, were gray. Today many relics have brown, reddish-brown, or tan-colored covers. These most likely were gray at the time of their manufacture and, over 140-plus years, the logwood dye used to color the fabric oxidized to a brownish hue. Thus, living historians seeking to improve the authenticity of their canteen should consider replacing their dark blue kersey cover with a gray-colored jean cloth cover; it is not unsuitable for early-war canteens to be covered in satinette. However, because canteen covers were not always durable, a canteen covered with any cheap, widely available material is also appropriate as a "field repair". Use of an old, 100 percent wool army blanket or a sock for a canteen cover is ideal in this respect. Use of field-improvised covers should be minimal because most surviving canteens appear to retain their original cover, and many "field repairs" on existing canteens may have been made by post-war owners.
New York Depot canteen covers were almost universally machine-sewn on the lower half and then hand-finished on the upper half, after the cover was slipped onto the canteen. Most Schuylkill Depot covers were likewise partly machine-sewn, although some canteens with entirely hand-sewn covers exist. Machine-sewn canteen covers were present only on factory-made examples and, obviously, covers that were repaired in the field should not have machine sewing.
Finally, based on period photographs, is appears that coverless canteens were rather common during the war, and were probably more prevalent than is seen today in the ranks of reenactment units."
Kevin Dally