The USDA has a taxonomy of heavy cream to skim milk that’s based on milk fat content. Other countries have similar taxonomies with different categories. As regards pre-Prohibition cocktails, which of these category distinctions are meaningful, and which ones are recent inventions? In most cases William only specifies “cream,” and yet he’s name-dropping galactometers in his precis on milk. The Ramos Gin Fizz calls for “cream or rich milk.” As someone who tends to have only whole milk in the house, I am not going to do a parallel tasting of a couple of classic cocktails with heavy cream, whipping cream, light cream and half-and-half. I imagine one of you jokers has already. Please let me know if the differences are significant and I must stock heavy cream, or if the differences are negligible and I have dispensation to use the less expensive light cream. Or maybe the heavy cream keeps longer…? I wouldn’t have had to ask if Trader Joe’s hadn’t newly designated their shelf-stable cream as a “seasonal product.”
You need the fat content high enough to form stable air bubbles in a stabilized network. I have made a passable Ramos with milk alternatives that tastes good but it relies on the egg white to make the foam and the froth and doesn’t come across as rich and ethereal. Heavy cream is the standard.
I’m more curious as to whether the fetish to get the stiff “Marge Simpson” head floating high over the Ramos’ glass makes for too much dilution with soda water as well as a concentration of the fat and proteins on top of the drink instead of inside it. The same way that I find the glorious photo-worthy head in a reverse dry shave of an egg white drink to be less satisfying of a sip than one with a meager head since the creamy protein-fat-air is stuck on top of the liquid in the former but integrated in the second.
I don’t make cream drinks often, but I have found whole milk, half-n-half, and heavy cream reasonably interchangeable in a pinch. The results aren’t identical, of course, but I’ve often been surprised how good a job whole milk does in place of heavy cream. Most of the time, it’s half-n-half that I have on hand (because of coffee) so that’s what gets used. No complaints. See also: Grasshopper - #8 by martin which I did test three ways.