Given that almost quarter of New Zealand’s economy is tied up in milk production, it continues to surprise me how little I know about it.
In my work for Homershams I call on many milk producers, so I have little excuse. Maybe I’m too much a city boy, and maybe I’m just ignorant!
I’m very fond of butter, as my waistline can attest. And I must admit, beyond over-whipping cream on occasions, I had little concept of the process.
The practice of churning butter is ancient. But it was only on a visit to a customer, that I discovered that this traditional churning process is seldom used today.
Butter is ostensibly a suspension of water in fat. It’s a so-called ‘inversion’ of cream (which is a suspension of fat in water).
Churning or whipping cream breaks the fatty molecules protective sheath and causes the familiar thickening (whipped cream). And if this process continues, this will continue and produce a more solid mass, and a runny liquid, called buttermilk.
My only knowledge of buttermilk was from childhood reading of Charlottes Web, where it was applied to the pig, Wilbur and in latter years in pancake mix (waistline again). But apparently overseas, buttermilk is a product that is purchased regularly from supermarkets.
This traditional method is called the Fritz process. A very few plants still use this.
A video on this process can be viewed here
More commonly, the Ammix process is used. Ammix takes highly concentrated milk fat (75%) and via heat-exchangers and high pressure, is formed into butter. The advantage is speed (minutes rather than hours) and consistency of finished products and the ability to blend with oils for special, spreadable butters.
Diagram Credit: https://nzic.org.nz/app/uploads/2017/10/3B.pdf
As an example of lack of consistency in the Fritz process, spring butter tends to be softer than summer butter due to the spring butter containing more low melting triglycerides. The Ammix process may be ‘tuned’ to produce consistent butter regardless.
So revolutionary was this process, that a bitter dispute arose in 1996 when U.K. customs could not believe that NZ butter could be made spreadable from the fridge (which is possible with the Ammix process) and that a different quota should apply. Lawsuits and arrests followed that were eventually resolved.
Interestingly, this was not the first time butter or it's competitors have fought bitter court battles. When margarine first came to the US, laws came into place to force that it be coloured pink to make it clear that it was not butter and make it less attractive to the lucrative butter customer.