Honestly? 1 in a week for one person is already too many. The fact that you're asking how many liters? means you probably already know the answer is too many.
I'm not saying this as some kind of teatotler or something, I go through 1.75L of Canadian whiskey every few months, but a liter in a week is a sign of a problem. If not for your life today (assuming functional alcoholic, sorry if I'm off base), but the long term health consequences. My buddy and I used to finish a bottle of everclear 195 in a week and a half to two weeks for both of us, and I know it was a struggle to come down.
Don't go cold turkey, but definitely work on bringing your intake down if you can.