how does milk that has been frozen taste afterwards?
Its perfectly normal. When we were kids the milk in those little cartons often arrived frozen. There were a couple of situations over the years where it happened to the plastic gallons we had. Just the day before yesterday I brought in a case (3gallons in quarts) of the shelf stable cartons (Its been below zero here for awhile) that I had forgotten to bring in from the Jeep. It doesnt damage the carton or anything, normal taste once its fully defrosted.
I use the coffee creamer bottles to freeze. Do not freeze a gallon. One big block. Hard to defrost. Mine tasted fine.
The milk tastes fine! Just the same as it tastes, before being frozen. Use half gallon (or, smaller) cartons….for size/weight. NOT plastic.
And, NOT half and half, or heavy cream. Those do not reconstitute well, imo and experience.