Indeed what you are detecting is a bit of alcohol there, but I wouldn't worry about it.
I did a 4 day yeast dough for pizza last month and it was one of the best doughs I had made,
a real soury-dough taste to it... I really enjoyed it.
Keeping it 7 days ? ... not sure how it is done, but I would expect that it would be a dough with lower
sugar and yeast content, and or colder temps for that length of time.