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msfuzz

Questions on large batches of jam

msfuzz
13 years ago

I am planning on doing a couple of fairly large batches of blackberry & raspberry jam in the next few weeks, and I have a few questions. I tried searching the forums for answers, but I think my Googlefu was weak, because I didn't see anything specific in the first couple of pages.

1. Most the BBB recipes are for 8 oz jars. What changes if you use 12 oz jars? Just the processing time? How much does it change?

2. I have a 16 qt Presto PC, and everything I've seen says that for BWB, you should cover the jars with at least 1" of water. I know my PC isn't deep enough to do that with 12 oz jars. Can I still BWB the 12 oz jars in it? I thought somewhere I'd read that as long as the water was within 1" of the top or something?

3. If I can't use 12 oz jars in this canner, and have to use 8 oz jars, I can only get about 10 jars max (maybe 12 if there doesn't have to be room between them?) in at a time. Can I fill all the jars (let's just say it will be 30, for these purposes), and process them 10 at a time? I have to process for 20 mins here, so that's at least 25 mins between batches. At least 10 of the jars will have cooled for almost an hour before they get processed if I do it that way. Is this a bad idea?

According to the BBB, a double batch of the regular jam with powdered pectin would make about 14 8 oz jars. I have 4 such double-batches to make. Just trying to find the most time efficient, but still safe, way to do it. :) Thanks in advance!

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