Cream, Whey and What?

November 21, 2009 6:45 PM

What sort of dairy product did I inadvertently create? Bad housekeeping details under the fold... queasy stomachs beware!

Yes, I'm one of those folks who leaves scary foods in the fridge until I get the courage up to deal with them.

In this particular case, I purchased a quart of minimally-processed (read: low-temp pasteurized, non-homogenized) whole milk from a local vendor in ...oh, let's say it was August but maybe it was actually April.... Anyway, the intent was to make cheese from said milk while it was fresh. That never happened but I did open the bottle once to use about a quarter cup for a recipe. After that, the milk remained, undisturbed, in my fridge until this evening when I finally decided to take care of it (I needed the bottle, otherwise I would have tossed it months ago).

The milk had separated into three levels in the bottle: the top was cream-colored and thick-looking; middle was sort of a beige but clear liquid; bottom was... milky-white. When I poured it out, the top, chunky cream stuff melted like butter under the hot water. The beige liquid just disappeared. The bottom white stuff... was a solid, like a cheese. That solid was soft and melted like mozzarella under the hot water.

Surprisingly, none of the stuff smelled particularly "BAD" - there was a mild dairy-cow-farm smell to the stuff.

I'll guess that the milk separated into the following:

Top: curdled/spoiled cream (would this melt like butter?)
Middle: whey
Bottom: cheese of some kind

Is this a way of making some sort of cheese? What kind? My question is purely out of curiosity; I don't intend to ever do this again nor did I keep any of the milk product for tasting purposes.

(For the record, this was the only disgusting thing in my fridge for the last few months. Really! [Unless you're like my brother and consider mushrooms disgusting...])

posted by LOLAttorney2009 to food & drink (5 comments total)

IANACheesemaker.

I'm guessing what fell on the bottom were the milk solids, usually called curds. I don't know what exactly you made, but it was probably closest to cottage cheese, or maybe ricotta, which are minimally or non fermented milk solids separated from the whey.

It probably broke up once the milk started to turn acidic. The milk then broke appart, like when you make clabber milk (mix lemon juice with milk) or cottage cheese (mix vinegar with hot milk).
posted by mccarty.tim at 7:18 PM on November 21, 2009

ricotta is actually made from whey, not curds. But here's my theory:

In opening up the milk once, you let in a tiny bit of bactetria from the air/your fingertips, the outside of the cap. this bacteria produced lactic acid, which curdled the milk, separating the curds and whey the same way that rennet and enzymes do in traditional cheesemaking. Over the long, long stint in the fridge, the pressure of gravity and the other liquid on top of it pressed the curds into a cheeselike block. the top level was definitely all the cream that rose to the top.
posted by Jon_Evil at 9:22 PM on November 21, 2009

To be more specific the milk solids that accumulated at the bottom are largely casein, the most abundant protein in milk. That's what makes milk white. It comes out of solution when the pH gets close to casein's isoelectric point (about 4.5 or slightly acidic) and yeah, this is likely due to bacterial action from when you opened it.

The stuff at the top was the fat, which is the main component of cream and floats because it's light, and it melted like butter because the fat from cream is the main ingredient for butter. Fat's melty. Not being homogenised meant you probably started with a pretty good cream plug up there anyway.

Then the whey was left in the middle (made of whey proteins, sugars, water). Most of the original water will be located here.

Each component probably wasn't pure, so some fat may be in the whey and some whey proteins can precipitate out with the casein, but that's pretty much it.
posted by shelleycat at 9:51 PM on November 21, 2009 [2 favorites]

Creme fresche, maybe? Milk solids, separation, spoilage. I'm assuming you didn't taste it, right?
posted by Gilbert at 10:31 PM on November 21, 2009

No, I wasn't brave enough to taste it! It didn't smell bad, as in 'spoiled', but it had a scent in there that I associate with cow manure, which put me off the idea of taste testing anything.

Thanks for the answers. :)
posted by LOLAttorney2009 at 12:16 AM on November 22, 2009