I understand that you reduce sauces to concentrate the flavours. But I am a bit confused why you do it on some sauces. e.g. I made a white wine sauce the other day. I've not been in the kitchen for that long so it is a bit new to me. I put some shallots and garlic sautéed them of and then added some wine to the pan. At that stage my head chef asked me to reduce it by half before I added the cream. What was the point in that as at the only flavours in the pan at the time were the shallots and garlic? Why couldn't I just add less wine and then add the cream? How did doing it that way improve the flavour?
I'm just interested in the reasons for doing it as obviously understanding the reasons makes you a better chef and helps you understand food more.