Cans

The ubiquitous “tin” can (many metal cans actually have no tin at all) provides information on both the age of an archaeological deposit and the activities that went on there.  Large piles of coffee, evaporated-milk, cooking-oil, and tobacco cans probably represent the kitchen area for a major work camp; fragments of tea tins and opium tins are often found at nineteenth-century sites occupied by Overseas Chinese.  Household dumps might contain a wider variety of food cans – fruits, vegetables, canned meat, baking powder, coffee – in smaller numbers than at a work camp.  No matter what the context, though, remember that large-scale canning in tin began very early – in the late 1820s.

The most important characteristics to note about cans in an archaeological site are these:

-Lid/Closure

-Seam Type

-Measurements

Also recording the opening type (punched, pried, lid completely removed) might help determine what was in the can – for example, whether it was liquid or solid.  And be sure to record any legible labels or lithography.

Can Lids/Closures

The kind of lid or closure a can has will help you identify when it was manufactured and, in some cases, what it contained. 

Hole-and-cap

• Can lids have central cap where food was inserted before sealing
• No vent hole; cans often swelled or burst during cooking
• 1810-1820

Hole-in-cap

• Same as hole-and-cap, but with tiny pin-hole in center of cap to act as a vent during cooking
• 1820s-WWI

Key-wind

• Cans opened by using a “key” to roll or tear away a metal strip from the top or side of the can; often used for coffee after 1917 (still used on some canned meats and fish [corned beef, sardines])
• 1866-present (key-wind tapered tins after 1895)

Hole-in-top (also called Vent-hole, Matchstick-filler, or Drop-of-solder)

• Cans have solid lids except for tiny pin-hole vent at center, which was sealed with a drop of lead solder after the contents were cooked
• After 1900
• Evaporated milk cans almost exclusively of this type by 1920

Sanitary

• Cans made entirely by machine, with one-piece lids – no caps or vent holes
• No lead solder
• “Modern” cans
• Commercially available by 1904

Can Seams

The other major technological change in cans was the type of seam closure.  Early cans were sealed along the sides and top with lead solder – first by hand, later by machine.  Solderless cans appeared in 1898 and quickly became the dominant type after the introduction of the modern “sanitary can” in 1904.

Hand-soldered seams

• Globby, irregular bands of lead solder along edges and around top, cap, and base of can
• Until the 1880s

Machine-soldered seams

• Bands of lead solder much thinner and more-evenly applied
• After 1883

Double locking side-seams

• First solderless cans; side-seams crimped on inside or outside of can
• Commercially available by the late 1890s
• Used on modern “sanitary” cans

Can Measurements

Other Can Tidbits

Condensed milk was first canned in the US in 1856, evaporated milk in 1885[1].

Kerosene was first canned in 1865 (in tall, rectangular cans with small caps).

Tapered tins, like those still used for some brands of corned beef, were first marketed in 1875.

The log-cabin-shaped syrup tin was introduced in 1897 and discontinued after WW II (with modern reproductions).

The first vacuum-packed coffee (in one-pound cans) was marketed by Hills Brothers in 1903.

Pocket tobacco tins (most-famously Prince Albert brand) were patented in 1913 and popular into the 1950s. See Pocket Tobacco Tins under Miscellaneous Artifacts.

The first beer cans were cone-tops (like modern-day STP^® cans), and were introduced in 1935.  The first all-aluminum beer can appeared in 1959; it was opened with a “church key.”

The first aerosol cans came out in 1945.

The pull-tab beverage can was introduced in 1962.