Protein/Fat Ratios of Milk & Cream

[rsterne]

I started reading the Univ. of Guelph eBook on Cheesemaking, and for those of you interested in exploring the scientific aspect of cheesemaking, it is an excellent resource....

https://www.uoguelph.ca/foodscience/book-page/cheese-making-technology-ebook

One of the topics is the standardization of milk so that you get the optimum balance between Protein and Fat for the type of cheese you are going to make.... You can find that section of the book at this link....

https://www.uoguelph.ca/foodscience/book-page/standardization-milk-cheese-making

I decided to look at what the Protein/Fat Ratio of various types of milk is, and how that relates to what I can purchase locally (our only grocery store stocks Dairyland products).... Here is a chart showing that data....



The two left hand data points are 1% low fat and 2% Dairyland milk, then the 3.25% Homogenized, and all the data points to the right of that are for various breeds of cows, plus goat, water buffalo and sheep's milk.... the latter two way over on the right.... The dotted blue line is a "trendline" drawn by MS Excel through all those points.... The horizontal red and black lines are the maximum and minimum P/F Ratios found in the chart at the link above from Univ. Guelph....

You can see in that link that various cheeses may use quite different fat contents to produce the optimum balance for that cheese.... For instance a Parmesan might want a P/F Ratio of 2.02, which works out to about 1.75% BF, while an Edam should be made from a milk with a P/F Ratio of 1.50, which is about 2.25% BF..... A Cheddar, according to the Univ. Guelph chart should start with a milk with a P/F of 0.91, which is pretty close to regular 3.25% Homogenized milk, while a Cheshire should have the butterfat content enhanced to a P/F Ratio of 0.79, which would be a milk with about 4% BF....

I found this to be quite the revelation, compared to the simple instructions you find in recipes to start with "whole milk".... I am already blending my own milk starting from skim or 2% and adding 18% coffee cream, but with this new knowledge I will be able to tailor the amount of cream I add to the cheese I am going to make.... The start of this process is understanding the Protein/Fat Ratios of the Dairyland Milks & Creams I can get, so I plotted those out on a similar chart, which is shown below....



It is my intention to build a spreadsheet that will allow me to choose either skim or 2% milk as a starting point, and have it calculate the volume of cream I need to add to get the optimum P/F Ratio for the cheese I am going to make.... When I get that done, I will add to this thread....

Bob

[Bantams]

How are you determining the protein levels?
Most skim milk has additional protein added (in the form of nonfat powdered milk) to achieve legal standards for solids %.
So skim and part skim usually have a slightly different protein % than whole milk. I also wonder if the addition of the dry milk powder affects the cheesemaking at all?

If you do branch out into using milk from small farms, be aware that those averages are just that - averages.
I've had cows produce protein levels anywhere between 3.1-4.0% and butterfat ranges from 3.8-8.0% depending on the individual cow and stage of lactation. So there's a huge amount of variability and it may make things trickier if you assume a specific p/f % without verification.
I personally have had great success making Tomme, Colby and Alpine styles with our whole milk (typically around 3.6 protein and 4.8% bf), but I do cease making the drier Alpine styles towards the end of lactation when butterfat values shoot up.

[rsterne]

The protein levels for the Dairyland milk are from their website, from the list of ingredients.... I realize there will be small differences, but at least I will be able to get a better idea of how much cream to add back to get close to what the recommended proportions are from the Univ. of Guelph.... "Standardizing" the milk for the cheese to be produced, which is what they call this process, is the first step in all their recipes....

The chances of us using anything other than the store-bought milk that is readily available to us is slim to none.... and I figure this should put me closer to the recommend P/F Ratio than just hoping that 2% or Homo milk is "close enough".... But, I'm a noobie at this, so I may be completely in error.... 

Bob

[rsterne]

I worked on my spreadsheet tonight, and produced this chart showing the % Butterfat, and the Protein/Fat Ratio, for various mixtures of 18% Dairyland Coffee Cream and their Milks, from Skim to Homogenized....



The concept is that I will look up the P/F Ratio that is optimum for the cheese I want to make, locate it on the vertical axis, and then find a (dotted) curve that crosses that P/F Value.... This will give me (on the horizontal axis) the volume of 18% Cream to add to 8 litres of milk to get that P/F Ratio, and by looking up at the solid line of the same colour I can see the % BF content.... The black lines are for Homo (3.25%) milk, the red for 2%, the blue for 1% and the orange for skim.... I have a table in my spreadsheet which the values in the chart came from to get more accurate readings.... For most cheeses, I will be adding between 1 pint (473 ml) and 1 litre of 18% cream to the appropriate milk....

For instance, let's say I want to make a Cheddar.... The Univ. of Guelph eBook says the optimum Protein/Fat Ratio for Cheddar is 0.91.... The red dotted line crosses a P/F of 0.91 when there is 1 litre of 18% Cream added to 8 litres of 2% milk.... The mix will have a butterfat content of 3.78%.... This just happens to coincide with the mix have been using for a while now.... While it is optimum for a Cheddar, there are better choices for a Parmesan, an Edam or a Cheshire.... Now I have a quick and easy way to determine which Milk to start with, and how much Cream to add to it.... 

Bob