How do they create Decaffeinated coffee ??

There are several processes used to decaffeinate coffee beans. Almost all use water in the process.
These processes are not harmful to a persons health, however they do havoc to the quality of the coffee bean.

The beans are soaked in water and then by using a solvent or an activated carbon, the caffeine is absorbed. Next the beans are re-soaked in the remaining water to reabsorb the lost flavor in the first extraction process.
The solvents never come in contact with the actual beans  but only the water solution containing the caffeine, so it is very safe.
In the Swiss water Process beans are soaked in hot water and the caffeine is extracted from the bean into the water.The beans are discarded and the remaining water is striped from the caffeine using activated carbon filters.
A new batch of decaffeinated green beans are soaked in the water and the natural coffee flavors left in the water are absorbed by the beans.
In the CO2 Process green beans are soaked in highly compressed CO2 which extracts the caffeine and is then removed from the CO2 using activated carbon filters, which are then used to extract the caffeine from the coffee again.

Roasting Decaf

Decaffeinated coffee beans are a little more sensitive to roasting procedures so care must be taken to roasting as not to destroy the bean or he flavor. Through experience & patience, I have found that to create a nice favorable roast comparable to non caffeinated beans. the roasting must be performed at a much slower rate achieved by reducing the temperature rate of the roaster and gradually getting up to the temperature where the first crack and second crack of the bean is the same of a regular roast.

This process produces a more even and favorable roasted bean. The beans once roasted do not have a nice shiny appearance as regular beans but rather a dull finish instead.

Decaf is generally more expensive because of the processes involved and for good reason.