spawn turning blue

Hi I just started my first attempt at growing mushrooms but i think something has gone wrong a made a mix of Coffey grounds and wood chips and autoclaves it i then inoculated it with wine cap spawn from mushroombox.co.uk the first 2 days looked good with the white threads moving through the jar but now on day 3 the surface has turned blue and the color is moving through the jar as well have i ended up with some sort of infection or is this normal for wine caps i thought all mycelium was white?