Young wines (less than 6 months old) have a lot of dissolved CO2. This forms carbolic acid and makes the wine perceive more sour than it is. For example the soda water (sparkling water) tastes different than still (tap) water from which it is made.
Globally, there are two widely used modes of degassing. One is agitating, which is achieved by stirring the wine using a stirrer. The problem with this approach is that it often leads to excessive exposure to air and oxidation.
The second approach which is widely practiced is vacuum degassing.
Attach it to your carboy of early fermented fruit juice and create the vacuum to remove the CO2 haze. Must have for early red wines. It has an overflow bottle that will ensure that excess vacuum is not created and a barometer scale to help you calibrate the vacuum levels created. The kit comes with various fittings, attachments and silicone tubing to connect to wide variety of secondary fermenter setups.
It is a low-cost hand-operated setup for those serious about the craft of wine-making and want to take it to the professional level before opening up a winery.
The best time to degas is before you add spices, Calcium carbonate and do final flavor or pH adjustments. This is usually 3 days before bottling.