To get an idea for what colours I am going to use in my designs I decided to look at the Magners logo. I imported it in to photoshop and uses the eyedropper to pick out the key colours for ideas. I made a mini swatch of these colours.
Green:
The green forms a ring around the logo. The darkness contrasts the brighter yellow in the center.
Red:
The red is in a block surround the 'Irish Cider' line under the name of the drink. It's quite a deep dark red which contrasts the bright colour of the yellow.
Orange/Yellow:
This colour is in the centre of the logo. It is reasonable to assume that this represents the colour of the drink.
Blue:
I included this in my swatch because it is a contrasting colour to the orange/yellow (on the other side of the colour wheel). I can use it to create a pleasing contrast in colour in my work if I need to.