Pressure canning: convert from 16oz jars to 4oz jars?

December 19, 2017 8:58 PM

Friend of mine is canning some low-acid veg from raw, and the recipe she has recommends, let's say 20 minutes in the pressure canner for 16oz jars, and 25 minutes for quart jars. She wants to can this stuff in 4oz jars. The recipe relies on cooking time in the pressure canner, so presumably overcooking it would be Bad Somehow. What's the algorithm she would use to find out how long to pressure can 4oz jars?
posted by All hands bury the dead to Food & Drink (5 answers total)

Your local extension office will be able to answer this for you in short order. If yours doesn't, a call to the OSU extension office has never, ever failed me. They can answer some obscure goddamn questions about canning, even if they don't publish those answers.
posted by furnace.heart at 9:42 PM on December 19, 2017 [3 favorites]

Best answer: Master preserver here. Processing times for half and full pint jars are the same. Just treat them like pint jars.
posted by Bistyfrass at 10:13 PM on December 19, 2017 [1 favorite]

Also the bad is merely the veggies will be soft/overcooked; they won't get dangerous to eat or anything. Way better in this case to err on the side of caution.
posted by Mitheral at 10:20 PM on December 19, 2017 [1 favorite]

Best answer: The time required has more to do with the diameter of the jar than the volume because that determines how long it takes for the heat to get to the middle. Or at least that's how I look at it.
posted by SemiSalt at 9:18 AM on December 20, 2017

This may be too late, but if part of the concern about overprocessing the veggies is that they'll be too soft, there's a ball product called pickle crisp that can be used to help veggies hold their shape. I use it when canning carrots and/or green beans.
posted by Bistyfrass at 12:50 PM on December 20, 2017