It is hard to find something that goes better with warm cookies than cold milk. Same with your cereal, a sandwich piled high, or even just as an afternoon thirst quencher. Really, it is hard to find something as good as that glass of cold, fresh milk. But have you ever thought about how it comes to be so cold and stay so fresh?
It starts at the cow – where it certainly doesn’t come cold. Our milking machines checks the temperature of the milk ion an ongoing basis as it gently milks the cow. Not only does it ensure quality milk, but it can be an early sign of an unhealthy cow when the milk is too hot or too cold. We look for 37.5-39.5 degrees Celsius. Talk about fresh! (Also recorded is how much milk the cow has given and how long it has taken. It even draws a graph to compare how many kilograms are given per minute)
Next step is a cooler that immediately cuts the temperature of the milk in half. It has thin plates (which is why it is called a plate cooler or heat exchanger) where the milk runs through. On the other side of each plate runs cold water, straight from our ground well. That cold water is warmed from the milk and sent to the water troughs for the cows to drink. The warm milk is cooled and sent to the bulk tank for storage and further cooling. This plate cooler saves a lot of electricity – since the electric cooler is only bringing the milk down from about 18C instead of 39C. (The MilkGuard unit shows the temperature of the milk as the bulk tank begins to fill up)
The bulk tank is where the milk is stored until it is ready for to be picked up (which happens every other day). Sensors in the tank keep the milk between 2C and 4C. There is also a large paddle that spins a few minutes every hour to keep the milk from separating.
When the milk truck comes for pick-up, the temperature is recorded down to a tenth of a degree. Nice and cold every time!
So now when you pull that milk out of the fridge, you know it has been cold all-along!
