Line colander with cloth, and pour in the yogurt, clabbered milk, or kefir.
Cut about three feet of string, bring the ends together, tie in a knot, and then loop the string through itself to make a slip knot (demonstration at 5:00 in the video). Gather muslin on all sides to make a pouch for the kefir to sit at the bottom, slip the string over the ends of the muslin, and pull tight.
Lift the pouch out of the colander, and hang to allow the whey to drain out through the muslin. I use the cup hooks in my pantry to hang the pouch with a small bowl sitting below it to catch the whey as it drains. Allow the pouch to hang for 12-24 hours.
Remove from the hook, drain any whey that has collected in the bowl, open the pouch, and at this point, you have what is called “yogurt cheese” or “kefir cheese”.
Add salt, and mix thoroughly with a spoon removing all cheese that has adhered to the muslin as you go.
Gather ends of the muslin, make a pouch again, and secure with the string. Resist the temptation to use a clean cheesecloth at this point. It may seem messy, but the original cheesecloth has now been inoculated with good bacteria. By switching to a clean cheesecloth, you will be reducing the strength of the good bacteria making it easier for the bad bacteria to cause spoilage. Hang for another 24 hours to allow the salt to pull out as much residual moisture as possible.
Remove from the hook, drain any whey that has collected in the bowl, open the pouch, and remove the cheese from the cloth into the bowl.
With clean hands, form cheese into 2” balls, roll in seasoning of choice and place in a clean jar. Continue until all cheese has been formed into balls.
Pour in enough olive oil to completely submerge the cheese, and cover with a lid.
If you have a consistently cool dark place like a cool pantry, root cellar, wine cellar, or cold storage, this would be the ideal place to store your cheese for up to a year.