Cream is separated from milk using a process that leverages the difference in density between the fat globules in milk and the other components. Traditionally, this was done by allowing the milk to sit, allowing the fat (cream) to rise to the surface. This method is still practiced in some artisan settings, but industrial production relies on a more efficient method.
Industrial Cream Separation: The Centrifuge
Modern cream production uses a skimmer centrifuge. This high-speed machine works on the principle of centrifugal force.
- Heating: Milk is heated to approximately 60°C (140°F).
- Centrifugation: The heated milk is continually squirted into the centrifuge, which spins at a very high speed.
- Separation: The centrifugal force pushes the denser components (skimmed milk) towards the outside of the centrifuge, while the lighter fat globules (cream) are forced towards the center.
- Collection: The cream is collected from the center, and the skimmed milk is collected separately from the outside.
This process is incredibly efficient and allows for the rapid and continuous separation of cream from milk on a large scale. The resulting cream can then be further processed into different types, such as heavy cream, whipping cream, or light cream, depending on the desired fat content.
Home Cream Separation: The Patience Method
While industrial processes utilize centrifuges, cream can also be separated at home using a simpler method. This takes considerably longer, but requires only one ingredient—milk. Allowing the milk to rest undisturbed in a cool place will allow the fat globules to rise to the surface over time, forming a layer of cream that can be carefully skimmed off.
Several online resources provide detailed instructions and video tutorials on how to make cream at home using this method. Here is an example.
Different Cream Types
The fat content of the resulting cream determines its type and use:
- Heavy Cream: Highest fat content (at least 36%), ideal for whipping and adding richness to sauces.
- Whipping Cream: High fat content (at least 30%), suitable for whipping into fluffy peaks.
- Light Cream: Lower fat content (around 18-30%), less likely to whip but adds creaminess to drinks and sauces.
