Not sure which milk to use for what you're making? This guide should help you decide...
Unhomogenised –
This is the best milk for cheese making as it is the least processed. The fat globules haven’t been broken up and may form a layer of cream at the top of the bottle. This milk is always found in the refrigerator and is common in gourmet or organic supermarkets. If the recipe requires unhomogenised milk, it will generally only work with unhomogenised milk.
Cheeses that require unhomogenised milk include mozzarella, specialty cheeses like camembert, brie and blue cheese, all hard cheeses. Feta and halloumi will also work best with unhomogenised milk.
Homogenised –
This milk is great for most cheese but not those that specify unhomogenised milk. The fat globules in the milk are broken up and evenly distributed so there is no separation. This milk is readily available in supermarkets and found in the refrigerator. It will have a relatively short shelf life, a maximum of 2 weeks due to the minimal pasteurisation treatment that keeps it ‘fresh’. Make sure you go for the full-fat version for best results.
When making cheese from homogenised milk, you can't be certain you will get a clean break and you may experience a softer curd which can be broken very easily. To help firm up the curd it is recommended that you add calcium chloride to your milk as per the recipe instructions. Homogenised milk works well for cottage cheese, cream cheese, quark and ricotta. Halloumi can work with homogenised milk but we recommend using unhomogenised milk for a better, squeakier final product.
UHT –
Ultra-High Temperature or Ultra Heat Treated (UHT) milk has been heated very quickly to high temperatures, for a short period of time. Due to the high temperatures during processing, this milk is not very good for cheese making as all the proteins have been denatured (broken up). This is usually found at room temperature in the supermarket and has a shelf life of greater than 1 month. Be careful when choosing your milk, sometimes they store UHT milk in the refrigerator. Double check the shelf life to ensure you have the right one. If a recipe requires UHT milk it will be specified. You can use UHT milk for simple cheeses that do not contain rennet such as ricotta, quark, yoghurt and kefir cheese. It is good to use UHT milk in quark and yoghurt because ultra heat-treated milk denatures more proteins than normal milk, which results in a better consistency. Other cheeses will not work with UHT milk.
For a little more detail - see the Mad Millie blog article.