Yes, I get the low acid part. I do a ton of canning and food processing. I’d have to add enough citric acid to get a pH of 4 before water bath would work. But that would taste terrible! I’d be better off pickling, where the vinegar drops the pH.
I’m looking for guidance on how long, at how many pounds of pressure. The starch in Water Chestnuts is pretty durable; that’s why canned ones are still crunchy. I guess I could experiment with 15 lbs. pressure for an hour and see what happens. I’d hate to ruin the product, especially after all the peeling!
Maybe canned Chestnuts (Castanea) would be similar?
