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.
I doubt anyone does. I certainly do not. It would not be environmentally optimum to do so.
There is a stat that if you wash a typical dishwasher load worth of dishes by hand (with avg faucet output of 1 gallon/min), you will consume:
While a dishwashing machine uses ~4—5 gallons of water. So dishwashers are actually good for the environment. I will clear of any bulk waste before loading a dishwasher, but I do not hand rinse because it would be wasteful.
It’s essentially the same when returning bottles for reuse. People count on the industrial cleaning to do the full job (though I started the thread to get an idea of to what extent it really can be relied on). The refund for the bottle return is the same whether the bottles are clean or dirty, so there is no incentive for anyone to pre-clean them in any way.
In terms of water use dishwashers are good however the detergents available have so many surfacants added that chances are using your dishwasher is poisoning both you and waterways.