64 oz (2 tubs) of plain non-fat yogurt yield about 16 oz of quark. Appropriate for “attack” phase.
You will need a large strainer, and a cheese cloth, or a cheese bag.
Pour 2 pounds of non-fat sugar free yogurt into large microwave-safe bowl, and heat for 5 minutes on high.
Stop and mix with wooden spatula, scrapping the walls, but do not mix too much, or quark will lose its structure. Continue heating for another 5 minutes.
Yogurt should separate and form large flakes. This process depends a lot on a brand of yogurt you are using, and on a power of microwave. I have really good luck with “Mountain High” brand.
If it is not uniformly separated after 10 min, mix a bit more, and heat for few more minutes. Avoid overheating, or your quark will turn rubbery.
Then take it from the microwave. Completely cover the strainer with two layers of cheese cloth, and drain quark over cheese cloth. Pull the corners of cheese cloth together, tie a loose knot, forming a sack of a sort. It will take a couple hours to drain. It is ready when is still moist but not dripping. You can speed up the process by putting some weight on a top.
Put drained quirk into a clean jar, cover, keep refrigerated. The taste should be mildly acidic, consistency – creamy and a bit grainy.