When you create global colors from scratch, you can set these to be spot colors.
About spot colors
In professional printing, spot colors can be used instead of CMYK process colors when your artwork contains a very limited color set. By setting these colors to be spot colors, print costs can be reduced significantly. You may also be able to accurately reproduce colors otherwise impossible with process colors.
As well as setting a global color to be a spot color, you can use pre-supplied PANTONE® colors, which will automatically become a global spot color in the Swatches panel's document palette when applied.
To create a spot color:
On the Swatches panel, select a Document palette from the palette pop-up menu. If no Document palette exists you can create one from the panel's Panel Preferences menu.
To create a spot color: