It doesn’t take long for mold to grow on empty beer bottles. Considering beer bottles get returned for a refund, you have to assume that the brewery will make an effort to reuse as many as possible.
I toured a brewery once and they showed us the big industrial bottle washing machine. They said the bottles get scanned for cracks using a laser, and rejects obviously get tossed. The question is: what about mold, which adheres quite well to the corners of the glass? I wonder if the laser also detects bottles that didn’t get clean. Or if they just figure the temps would kill everything and just be considered safe enough from there.
As far as I know, in the US, recycled glass is recycled, not reused, so they basically waste a lot of energy to melt the glass back down and make new bottles.
Reusing can definitely be done effectively, though. Homebrewers do it all the time with pretty safe chemicals. If you have industrial machines and chemicals, you can probably get the glass sterile, and if not sterile, then definitely close enough.
In Europe they charge 10¢/bottle for simple bottles and 40¢/bottle for the fancy clamp-down style. Then that gets refunded when they are returned. It’s a bit of a hassle because some brewers do not participate, in which case the reverse vending machine rejects the bottle which means you then have to carry it to a glass recycle bin. The brewers that do not participate use a thinner more fragile glass that would be unfit for reuse. So consumers have to stay on their toes and keep track of which brewers participate. Can get quite tricky with the obscure artisinal brews.
Ireland is introducing the same concept for plastic bottles of charging a fee for them then returning the fee in a reverse vending machine. I can’t imagine reusing those. They must be recycling them.
Yeah some states have deposits on bottles/cans that you get back through the vending machine thing, but the only bottles that actually get reused are some fancy milk brands.