Feta is a brined cheese. Sometimes feta stored in brine gets soft and can even dissolve completely. This is due to calcium leaching out of the cheese. If desired, you can add calcium chloride to the brine as insurance against softening. Lipase is an enzyme that may be added to give the feta a punchier flavor. Both calcium chloride and lipase are available from cheesemaking supply companies.

Combine in a large saucepan:

Heat gently until the temperature of the milk reaches 86°F. Turn off the heat and add:

Cover and allow the milk to ripen for 1 hour.

Meanwhile, prepare a coagulant by stirring together until thoroughly dissolved:

Add to the milk and stir for about 30 seconds. Cover and let the curd form, undisturbed, for about 1 hour. To test the curd, wash your hands well and, using the back of your hand, gently press the curd mass down at the edge where the curd meets the pan. The curd should pull away neatly from the edge of the pan. Cut the curd into ½-inch cubes as shown and allow it to rest for 10 minutes. Gently stir the curds for 20 minutes. At first, they will be fragile, but they will firm as they expel whey.

Line a colander with a clean flour sack towel and set it in the sink (if desired, place over a bowl to save the whey for another application like Ricotta). Scoop the curds into the colander and let them drain for 10 minutes. Bring the corners of the towel together and tie them with kitchen string. Hang the curds from the sink faucet (or a cabinet knob or hook) and let the whey drain into the bowl for 4 hours.

Unwrap the curds, flip the curd mass, rewrap it, and hang it again for another 2 hours.

Unwrap the curds and cut into 1-inch cubes. They do not need to be perfect. Toss the cheese in a large bowl with:

Set the cheese cubes in a colander set over the bowl, cover, and place in the refrigerator. Allow the cheese to continue draining for about 2 more days; every so often, pour off the whey that has collected in the bowl. The first couple of times you drain the cheese, you may have to manually separate the cubes as they tend to knit together until they firm up.

When the cheese stops emitting whey, make a brine solution using:

Whisk to dissolve the salt. Pack the cheese cubes into a clean 1-quart glass jar and pour the brine over the cheese. If possible, use a plastic lid on the jar as the acidity of the cheese and the salt in the brine cause metal to corrode (or cover the top of the jar with a double layer of plastic wrap, then seal with a metal lid). Store, refrigerated, indefinitely. When you remove pieces of cheese from the jar, use clean tongs or a fork so as not to introduce bacteria or other contaminants into the jar.