Do not be surprised when brewing your own coffee at home, there are small bubbles of foam when the brewing water meets the coffee grounds, this is a common process, but what is the reason the foam appears. Surely you guys don't know about that right!
the following explanation, Starting from the Roasting Process When the coffee beans enter the roasting stage or roasting, at a level that is not too much carbon dioxide appears due to heating the roasting process, the gas is trapped inside the coffee beans. And actually after the roasting process of coffee beans is finished, CO2 gas is gradually released naturally which is better known as * degassing *. The reason is, the froth from coffee powder when brewed can be used as an indicator that the coffee beans used are still in fresh condition or not. When the coffee powder meets hot water, the CO2 gas comes out faster than the reaction of the hot water and forms small froths from the wet coffee powder.
