How long can I infuse purple basil in distilled vinegar before straining it?

My approach is a bit different when I make herb vinegars. I stick the herbs in the final serving bottle, never to be taken out. This typically means buying bottles of white wine vinegar, pouring off a bit, pushing the herbs into the bottle, then topping off.

I can't point you to any scientific research that proves that storing vinegar in glass is safer than plastic (and I'm sure the plastics industry would tell you it's fine), however I avoid plastic as much as possible.

I use distilled white vinegar for household cleaning purposes (including adding some to my laundry), but I don't cook with it. That's just personal preference about how it tastes.

We don't know how much basil you are using so you should go by taste for your method rather than count days on a calendar.

Good luck.