Why pasture-fed cream is faintly yellow while buffalo cream stays white
Cows grazing on grass, Jerseys especially, take in carotenoid pigments from plants, and separation concentrates them in the fat. That tint gives cream a slight yellow cast and even named a colour. Cream from goats, water buffalo or grain-fed indoor cows lacks the pigment and comes out pure white.
Cream is simply milk's fattier layer. Left to stand, the less dense butterfat floats up and can be skimmed off as gravity cream; factories spin milk in centrifugal separators instead. Cream skimmed from fresh milk is sometimes called sweet cream, to set it apart from whey cream, a cheese-making by-product that is thinner and tastes salty, tangy and a little cheesy. The same carotenoids behind cream's tint also turn butter yellow.
Fat content defines the grades, and every country draws the lines differently. Australia and New Zealand require plain cream to hold at least 35 percent milk fat. France, under a 1980 decree, sets a 12 percent minimum and reserves the label crème fraîche for pasteurised cream packed on site within 24 hours. Russia splits cream into normal, from 10 to 34 percent, and heavy, from 35 to 58 percent. In Canada, a carton called half-and-half might hold anything from 3 to 10 percent fat depending on region and brand.
Fat level also dictates behaviour. Whipping needs more than 30 percent fat so that beaten-in air can turn liquid into a soft solid, and cooks prefer double cream in hot sauces because it resists splitting. Bacterial cultures sour and thicken cream into sour cream, milder crème fraîche at around 28 percent fat, or Norwegian rømme. At the rich extreme, British clotted cream reaches roughly 55 percent fat through slow heating of whole milk, much like Indian malai.
Because the word is legally protected in many places, imitations dodge it with spellings such as creme or kreme, or call themselves whipped topping. Yet some names survive without much dairy at all: British ice cream may contain non-milk fat, and salad cream is a non-dairy condiment. Cream added to coffee can also form oily blobs, a flaw known as feathering.
Source: Cream
