Finding liquid on top of yogurt is commonplace for most yogurt eaters. That yellowish liquid is annoying and can be disgusting to some. Many people pour the liquid off the top while others stir it back into the yogurt. What is that liquid on top of yogurt and what should be done with it?
The liquid is called whey and is one of two primary proteins found in milk. The other protein is casein. Yogurt is created by adding a bacteria (good bacteria called Streptococcus thermophilius and Luctobacillus bulgaricus) to heated milk. This causes it to ferment. During the fermentation process, the casein protein makes the thick portion of yogurt, while the whey remains a liquid. The whey is strained out during the manufacturing process but not all is removed. The more straining of the whey, the thicker the yogurt. The whey separates and moves to top as yogurt sits in your refrigerator or is disturbed, while the thicker portion remains on the bottom. Essentially, blame the whey for that unsightly yellow pool atop the creamy whiteness of your yogurt.
The liquid (whey) on top or in yogurt is harmless and normal to many dairy products like sour cream or cottage cheese. It contains nutrients like calcium, potassium, and protein so it is best to stir it back into the yogurt. It can also be strained into a container and used in smoothies or recipes for additional nutrients. If you don’t care for the liquid or want a thicker yogurt, simply discard it into the sink and enjoy.