Chest Gunk - a bit random

Hey,

This is a bit of a odd question I know, but recently I have been bringing up super think gunk. It is clear/white. It's not the normal green/yellow that you would get if you had a chest infection.

Does anyone have any ideas why it is much thinker than the normal gunk I bring up. My asthma seems to be fine at mo so not worried about it, just a little confused. It's all a bit werid for me.