How is canned corned beef made?

what gives canned corned beef its flavor

Consider the flavor of canned corned beef as similar to freshly cooked brined corned beef, with these exceptions:

• The canning process requires product in the can be heated under pressure to 250+ F, this high temperature will change flavor notes and texture.
• Food labeling standards allow 10% of canned corned beef to be a flavored solution. This will have a large impact on flavor. This will generally be a proprietary trade secret.
• Canned Corned Beef will most likely be made from lower quality cuts of meat (ie. the one not good enough to be sold as fresh corned beef brisket). This lower quality cut will have a different flavor. Probably fattier.

there is very little information on the canning process of canned corned beef

I just Googled, you're right, very little info. I do not home can, so I can't provide a lengthy answer. I found a historical recipe here, Ball Blue Book of Canning and Preserving Recipes:

Note: That recipe will not provide you with something similar to commercially canned corned beef. It will be a jarred liquid and chunks, it might be better than canned.

For information on commercial canning, Google the term: corned beef retort. A retort is what commercial canners use to sterilize canned products.

• Corned Beef (US) - aka Salt Beef (UK)
• Canned Corned Beef(US) - aka Bully Beef, Corned Beef (UK)

In the United Kingdom, corned beef refers to the variety made from finely minced corned beef in a small amount of gelatin (bully beef; from the French bouilli "boiled"), and is sold in distinctive, oblong cans, just as in the United States and Canada, or in slices from supermarkets. It is mainly imported from Argentina, Brazil, or Uruguay.[17] Bully beef and hardtack biscuits were the main field rations of the British Army from the Boer War to World War II.[18] It is commonly served sliced in a corned beef sandwich. Hash and hotch-potch, in which potatoes and corned beef are stewed together, are also made. Tinned corned beef is also used in mainland Europe.[19]

As mentioned the meat would be most likely be low grade, tough and unpalatable "meat" (possibly Mechanically Recovered Meat, depending on the regulations on where it is sold) is likely brined before being packed into the tin and canned.

So in summary, the cuts of beef and the canning process used is the major factors in it's taste.

The production of corned beef isn't discussed much, as manufacturers believe consumers will likely be put off. The "meat" (whether it is MRM, or everything except the blood, skin and bones is debatable), either way it isn't comfortable eating knowing that.

In the same way that ham looks and tastes different from plain or just salted pork, the use of nitrites/nitrates in the preservation of corned beef not only keeps the meat pink when cooked but also affects the flavour.

This, to me, is the main reason canned corned beef tastes very different to other varieties of fresh or preserved beef