Fat content of whey?

[Hari_Seldon]

I make ricotta cheese by heating milk to high heat with buttermilk and sour salt (I think it is CaCl) until it curdles and drain off the whey. The volume reduces by a factor of about 4. This means that, starting with 3.25% (the abomination that passes for “whole milk” in Quebec, it should have a BF content of 13%. But I am sure that some of the fact goes awhey. Many years ago, I watched a cheesemaking factory in Gruyere and it was worth their while to put the whey through a cream separator.

Googling the question just leads me to many sites on how to lose fat by eating dried whey protein, which is no help. Does anyone know even an approximate answer?

[Enilno]

Not exactly what you’re looking for, but from here it looks like the amount of milk fat retained in cheese is around 90% of the milk.

Also from here:

Some of
the nonglobular fat will float and form large pods of free
fat on the milk surface. This fat will be lost to the whey
after the coagulum is cut. The main portion of milkfat
released to whey occurs during the initial stages of curd
treatment. Increases in temperature and curd handling
during cheesemaking also lead to increases in whey fat
(21). However, the size of intact fat globules in whey
decreases as the cheesemaking procedure proceeds.
Whey obtained at pressing contains the least fat, but the
highest proportion of small fat globules.

[Enilno]

Too late to edit but more relevant to the OP, according to this site acid whey has a fat content of .22 g per cup, which is roughly .1%, while sweet whey has .89 g per cup or around .4%.

[Hari_Seldon]

Ok thanks. Since I use acid (it is citric acid, not CaCl which is just a salt anyway), I assume that nearly all the fat stays in the cheese.