I noticed that cutting half & half with water does not make it taste like whole milk. What is the reason for this?
I'm trying to apply some systems thinking to my understanding of ingredients.
The difference between whole milk (or any milk, really) and half-and-half is one of fat content, not overall concentration. Half-and-half gets its name from being a 50/50 blend of milk and cream, which normally separate because the less dense fats concentrated in cream float naturally to the top of the mostly-water milk. However, milk also contains a number of other proteins, sugars, etc. that give it flavor. When you dilute half-and-half with plain water, you're diluting the fat content (potentially down to a similar range as contained in whole milk) but you're also diluting all those other flavorful components. You wind up with something that has the right fat level but not enough of anything else, and which tastes somewhat flat and flabby by comparison with proper milk.
I've done some experimentation on this topic and I've come to the conclusion that one of the main flavors missing is sweetness. If you look at the sugars in half & half they are usually lower to start with than whole milk. When you dilute it to try to match whole milk you end up with quite a bit less sugars in the final product, even if concentration of milk fat is about the same as whole milk.
Adding in some sweetener to the diluted mixture makes the flavor much closer to that of whole milk. The actual amount of sweetener depends on the type of sweetener and your individual taste. A tiny bit of salt can also help. It's difficult to obtain a perfect match but you can get pretty close with this trick.
The reduced sugars can be exploited if you're on a low glycemic diet, substituting diluted heavy cream, half & half, or other high milk fat ingredients for other types of milk, then adding in lower glycemic index sweeteners.
Pretend milk is Kool-Aid
The cream is sugar and the Mr Strawberry is a powder with strawberry taste but no sweet.
I am supposed to mix 1 pack Kool-Aid, 1 cup sugar, and 1 gallon water. I mess up and put in 2 cups of sugar. If I dilute down the sugar with a gallon of water I get the sugar ratio correct but now the Kool-Aid ratio is 1/2 what it is supposed to be.
If you dilute half and half to get the fat ratio down you also dilute the other stuff. Half and half is not concentrated milk. If half and half was just remove half the water from milk it would work. Half and half is adding cream to milk to increase the fat content.