Given the background description of some cooking related query, summarize the question into a title
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Question: The bag of coffee I am using instructs to "Add 2 1/2 tablespoons (37 ml)" of ground coffee. When I measure out 2 1/2 tablespoons onto my food scale, it only comes out to about 13 ml. Why does my 2 1/2 tablespoon measurement not equal 37 ml?

Answer: Why does my 1 tablespoon of coffee grounds not equal 15 ml?


Question: I have always roasted my beets in a bit of vinegar in the bottom of the pan like 1/4" or so. It is how I was taught. But why do it? What does the vinegar do for the beets?

Answer: Why roast beets in vinegar?


Question: When I make yogurt, I freeze some of the yogurt for the next time. However, I concentrate the yogurt by pouring it into a cloth, and extracting the yogurt whey (I do not know if it is called whey like cheese).Is the culture in the yogurt whey? Do I lose culture by concentrating the yogurt?Is salt harmful for the culture? Do I necessarily need to store the culture before adding salt to yogurt?

Answer:
How to catch culture out of yogurt?