Curdling and cheesing is our way of making dairy product last longer. Cheesing can involve almost every art of food preservation previous to it and then some. Cheesing itself, curdling is ancient. In this we induce a change by chemical agents (usually acids or enzymes) in which the curds (solid product) get separated from the whey (liquid byproduct) in a process of rapid dehydration. The curds can be processed in any number of ways for long term storage. What most of us think of as cheese gets pressed and aged.
The levels of processing are hierarchical in terms of long term storage. At the shortest term is fresh. Curdling to remove H2O leaves a longer lasting product. Cheesing removes more H2O so it’s product lasts even longer, especially when salt is added. Aging cheeses can remove even more moisture and also allow for all kinds of GOOD fungi and bacteria which not only can flavor our cheeses but set up even more hostile environments for other micro-nasties we don’t want in our lives. Going one step further, we dip cheeses in hot wax for storage which puts a disinfected and air-tight layer around the cheese, even further inhibiting decay. Finally, cheeses can be canned, making a truly long term storable food. Canned cheese and butter can be bought from numerous suppliers. It’s amazing to thing the stuff starts as a liquid.
Storage terms or longevity of cheese is pretty much up in the air. Most of the cheese-making world considers maximum term to be about 10 years but French people would argue. For my cheeseworth, about 5 years produces some pretty sharp cheddar. There’s some older stuff that’s just sublime at parties but I wouldn’t eat it day to day. Cheese tends to harden and crumble over time as fats slowly sweat out. Younger, more elastic and milder cheeses are good for sandwiches.