CO2 cartridges are used to pressurize the bottle. To keep everything cool you can use a standard water cooler with a few simple modifications. The 3 liter bottle is too tall for some coolers so ...

After pouring 3 litres from the 5 litre bottle, there will be 2 litres left. 5 – 3 = 2 litres The smaller bottle now has 3 litres of juice, so it has more juice. Be your own measurement ...