you can buy all different kinds of candy sugar. amber, dark, light.....depending on how dark it is it will change the color to some degree...
According to AHB:Belgian candi sugar is cystalized beet sugar. It comes in diamond form without strings, and is used to produce some of the unique Belgian beers. Candi sugar increases the alcohol level and can be used also to change the color of the beer. Dark candi is generally used for Dubbel, Old Bruin, and holiday styles.