Hi,

Well when milk makes it to the dairy plant it is separated into skim milk and cream using a centrifuge. The cream is then added back to the skim milk using a homogenizer in varying proportions to yield 1%, 2%, 4% , and half-and-half. Straight skim milk is what you would know as trim milk in Australia and of course the cream is generally called whipping cream.

The homogenization process changes the sizes of the milk fat globules so that they stay incorporated in the milk rather than separating out like you would be familiar with if you've seen raw milk that has been in the chiller for a few hours. Basically, unhomogenized milk is by necessity skim.

Skim milk will foam using steam but it forms a coarse, very airy foam that isn't particularly flavorful or very useful for making latte art.

Regards,

Cory

This alt.coffee thread may be relevant. It mentions additives to reduce foaming during processing.

I found an article today from Sydney Morning Herald where they compared some of the milks available. They compared flavour (for drinking not coffee)and one that came out well was the Parmalat Full Cream Unhomogenised. Another was one from Queensland which surprised me as I would have expected better flavour from cooler climates. Some apparently had quite nutty overtones. Unfortunately I haven't tasted unpasterised since I was a kid so can't remember it but it is suppose to be very different.
Another article I read said that the morning and afternoon milkings will also differ in flavour also across the seasons due to the protein content varying. I'm sure cheese makers will really notice the differences.

Dairy Farmers here produce a milk called Crema which I think they are marketing to Cafes. I no longer see it at the local supermarket. I haven't tried it but they add extra proteins to improve foaming qualities. From my reading today I recall something about high protein having poorer flavour so is there a trade off here between flavour and texture?
I also found an interesting discussion on the Crema magazine site.
http://www.cremamagazine.com.au/forums/YaBB.cgi?board=cremamag;action=display;num=1145520861

Thinking of antifoaming agents does the container ie HDPE or coated board (tetra pack) cartons affect it. All the cafes seem to use the bottles.

Rosemary

Thank you for the explanation. Being somewhat of a farm boy I know it changes with the season/feed/cow that is used but did not realize it was that dramatic. Most milk processors do pool from the local farms and then rebottle for multiple brands. I am sure there are a few exceptions, my local dairy sold its own milk from its own Jersey cows, until someone died from a batch of bad milk. Now you can only buy ice cream and the milk in the coolers is supermarket brand.

Gas is distributed the same way. If BP wants 10K gallons, they pump in 10K at the head end of the line and take out 10K at the end. It is a shared pipeline so the fuel is all the same, only the additives are different.

I have spoken with Parmalat/Pauls consumer information and they have confirmed that we will see variation in protein content depending on the feed the cows are on and that we may get overtones in the milk too dependent on if there are weeds like onion flowers in the paddocks. So I guess it is not surprising we may get these changes and a review of a milk from last week may not correlate with what we taste in a months time.

Rosemary

I usually use 2% milk and never had any problems until we switched to organic milk. The milk tastes great but there seems to be a lot of varibility between brands when it comes to foaming. Horizon organic has never given me a problem, but Organic Valley hardly foams at all. Last week my wife bought a couple gallons of Whole Foods store brand organic and it's the worst of all. No matter what I do the foam comes out as large sea bubbles which collapse immediately.

Rosemary wrote:Do you know if homogenised or unhomogenised has better foaming properties?

I have never been able to get microfoam out of unhomogenized milk. I suspect in this case it's not just me, since at the USBC several contestants were using a milk from the same dairy that sells my local unhomogenized milk, Strauss Family Creamery. Their "barista milk", though, has been homogenized at the frightening pressure of 1000 psi, along with being made from milk from a different mix of breeds than the regular stuff.

Also, if I want a slightly creamier texture and easier foaming, I sometimes add non-instant powdered milk, about two tablespoons per quart. Note that this is non-instant, which is nonfat milk powder that's been spray-dried and has the texture of talc. It has to be added to the milk in a blender to get it to mix. The instant stuff that's more common will give a grainy texture to the milk.

Best,
David

cannonfodder wrote:Gas is distributed the same way. If BP wants 10K gallons, they pump in 10K at the head end of the line and take out 10K at the end. It is a shared pipeline so the fuel is all the same, only the additives are different.

Seeing as it's the additives that make the differences between fuels in the end anyways (and they can make HUGE differences in performance, efficiency, economy, and environmental impact depending on those additives) it's kinda like saying that all the water coming out of the coffee machines all over the world comes from the same source, originally, and the only differences is the regional additives and filtering, and what blend of coffee it's being pushed through... so espresso is essentially the same everywhere.
I dunno much about milk or its distribution (I do know that Ben and Jerry did some research, and chose my cousin's farm for it's milk quality) but if the milk analogy is to be held as a parallel, milk can be all from different farms and mixed together at a processing plant and distributed as hugely different product in performance and quality, under a number of differing brands names and types.

great thread.

I think I'm going to try the davidmlewis bit about adding nonfat/non-instant powdered milk