I was just wondering if there's any reason I shouldn't try cooling wort with plastic PET bottles that are %70 filled with water and then frozen. I'm doing BIAB brews at home and have been chilling with ice baths but it takes a while to chill to fermentation temps. My idea is to take clean PET 500ml plastic bottles and fill them with roughly %70 water and stick them in the freezer. Once the wort is done boiling I'll put the kettle in an ice bath and sanitize the frozen bottles in starsan. When the wort gets to around 120F I will put in the sanitized PET bottles to help cool down the wort. Is there reason why I shouldn't try this method of cooling the wort?