Macallan Whisky

I opened a bottle of Macallan Fine Oak 15 tonight. What is remaining is the whiskey?
I have still three quarters of the bottle left and entertain plan with her five weeks from now. How will you open the bottle of whiskey affect the way one months now? 3 months?
It can last indefinitely if corked and stored properly. If you're entertaining five weeks from now, probably going to be fine. However, I suggest you another bottle or two, and end what have now.
The Macallan Estate : Single Malt Scotch Whisky