grape juice info

Question

Dear Rabbi, Below is a note I sent to a local posak. He was unaware of the issue. Also the pasteurization temperature was thought by many to below bishul. Dear Rabbi.... I just had another long conversation with Welchs. As you probably know, grape juice, by definition has to be pasteurized to stop the fermentation process. ( It was invented by a teetotal Dr.Welch for sacramental purposes in his " dry " church.) They confirmed to me that the unpressed grapes are pasteurized at 180 degrees( to kill the bacteria on the skins that otherwise would start the fermentation process), and never below that temperature. This is not a new process. Dr.Welch himself cooked the grapes, whole, at that temperature. I asked what was different when the OU had a run there. Apart from supervision, apparantly nothing. It seems, therefore, that from the very beginning, grape juice was always cooked before it could be touched by a non-Shabbat observer. All the best, Martin