According to online conversion, 1 quart (US/liquid) is almost 1 litre. I usually use 1.5 litres to make ricotta. The yield is more substantial than goat’s milk.
The whey has a bit of acidity in it so if you use it in something it’ll have some sour taste. You can also drink it.
To make traditional ricotta you’ll need to use whey which is from making cheese, yogurt or kefir.
Here are photos from my recent experiment last week posted on the cheese thread:
The cherries were marinated in Pedro Ximénez, a sweet wine.