This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
Sue Harris wrote:
I have recently seen some unlined "copper jam pans" for sale, supposedly
to be used in making jam. I am wondering if anyone here has had any
experience with these - - are they safe? I thought that unlined copper
reacted with acidic foods (which fruit jam certainly would be!).
Arno Martens replied:
I always thought copper MUST be tinned (led, cadmium and antimony free)
before it could be used for ANY food, liquid or solid.
On Food and Cooking, Harold McGee
"In 1753 Sweden outlawed the used of copper ( unlined is meant) cooking
pots in its armed service. In the early 19Th century Britain issued
health warnings of the health hazards posed by pickles, beer, bakery
products and candies that had been prepared in copper vessels.
Copper About 1/10 gram of this element is incorporated into the body,
with the highest concentrations in the liver and brain. It plays a role
in the formation of hemoglobin and of phospholids, an is also involved in
bone development and energy production. Organ meats, shellfish, grains,
and most other seeds are good sources. Dietary deficiency of copper is
rare, and excessive intake can cause damage to the liver, kidney, and
brain. For this reason, and because copper metal readily reacts with
many foods, the use of unlined copper utensils in not recommended."
Consider that canned foods may be eaten by persons on medication.
This presents a great potential for unwanted, unknown and possibly
very dangerous side effects.
Certainly a copper load uptaken by a child from food prepared in an
un-lined copper pot would be more toxic than the same amount to an
adult. No doubt the symptoms in that child would be never be seen
as copper poisoning but would be called colic, stubborn or something
else. In the middle aged and older adult the degeneration from
accumulation of copper would be seen as aging, the effects of having
lived life of consumption or simple dementia.
Live long, live well - use utensils which are safe.