Whey is often called for as a culture starter in foods like lacto-fermented vegetables, beverages, and grains and flours. Straining whey is also a method used to thicken some cultured dairy. To obtain whey, you can strain yogurt, kefir, cultured buttermilk, clabbered milk, and some cheeses.
Whey is full of the beneficial bacteria and enzymes found in these cultured dairy products. By using whey as a starter, the ferment is inoculated with the specific cultures in the whey.
Straining whey is easy. The main objective is to remove any dairy solids from the liquid whey so that the whey isn’t as perishable. Plus, straining whey will leave you with a thicker cultured dairy.
What You'll Need to Strain Whey
Instructions for Straining Whey
Place the strainer so that it is sitting atop the rim of the bowl, leaving a few inches of space below the strainer. Line the strainer with the cloth or coffee filter. Place the cultured dairy inside the lined strainer. Be sure to keep the cultured dairy within the cloth or filter.
After a few minutes, the whey should begin to slowly drip through the lined strainer into the bowl and be a translucent pale yellow with no white dairy streaks.
Note that the cloth must be very tightly woven in order to keep the dairy solids from dripping through. Coffee filters and tightly woven tea towels generally work the best.
If you find that after the first straining there are still some of the dairy solids in the whey, simply strain a second time. Use a clean towel or coffee filter and pour the whey through the new filter.
Straining whey for a few hours will result in a soft, easily spreadable cheese, with a texture similar to Greek-style yogurt. Straining whey overnight will result in a denser, cream cheese-like texture and will yield more whey in the end. Overall, the longer you strain the cultured dairy, the more whey you'll have and the thicker your dairy will be in the end.
How to Store Whey
Store whey in a clean jar in the refrigerator, where it should last for months. The cheese can be stored in a separate container for a week or so and used as a cream cheese replacement or as a very thick spoonable snack.