Return to the Harvest Forum | Post a Follow-Up

does jam jar size matter?

Posted by thefishers OH (My Page) on
Thu, Apr 26, 12 at 11:52

I'm planning on canning some jam as fruits come into season this year. We eat loads of jam.

All of the jam canning recipes always call for 8 oz jelly jars. Is it OK to use bigger jars - say 16 oz pint jars?

The canning recipes always warn not to changing anything for food safety reasons. I'm wondering if the time in the steam bath has to change depending on jar size?


Follow-Up Postings:

RE: does jam jar size matter?

if the time in the steam bath has to change depending on jar size?

Steam bath???

Most all NCHFP jam/jelly recipes are for either half-pints or pints and the BWB processing is the same.

As long as it is an acid fruit recipe rather than one of the low acid fruits then it will make little difference safety wise. Quality may suffer with some of the more complex recipes if you increase the jar size.


RE: does jam jar size matter?

16 ounce of 1 pint canning jars use the same processing time for jams as do 8 ounce jars. I usually always use 16 ounce jars because of the increasing costs of lids (1/2 as many with double sized jars).
I process jams for 10 minutes to eliminate need to sterilize jars.
Now, this is the rule with jams because it is a high acid food and you are processing it to kill any molds that might develop. You are not at risk from the bad boys that you might find in a low acid food like green bean or corn.
So make jam in pint jars to your hearts delight without worry of any kind.
Jim in So Calif

RE: does jam jar size matter?

  • Posted by morz8 Z8 Wa coast (My Page) on
    Thu, Apr 26, 12 at 20:39

When I'm not gifting them and am out of jelly jars, I will use my everyday wide mouth (16 oz) pints for jelly and jam....The finished product is fine and DH doesn't mind a bit what his jam is processed in or what kind of jar he is opening :)

As above, 10 minutes BWB so I don't have to sterilize jars.

RE: does jam jar size matter?

You can get softer jams in the pints.

Also, I hope you are not using a steam canner as they are deemed unsafe for canning of any foods.

RE: does jam jar size matter?

linda lou, i like the 12 oz. jars for jams. my ball book of home preserving calls for 8 oz. jars in all recipes . if i use 12 oz jars in a 10 minute BWB, will that be okay and also give a firm product ?

RE: does jam jar size matter?

Not Linda_Lou, but yes, you can. The risk of textural change (i.e. softening) is more likely with a delicate jelly. I've never noticed any difference with other preserves.

I disagree on the use of a steam canner for high-acid sweet preserves as long as you are willing to accept the possibility of waste from mold. But it's not "unsafe" per se since mold is easily detectable. I'm only referring to this single category of foods, not other canned goods. Boiling water bath is still the optimal choice for long-term storage.


RE: does jam jar size matter?

carol, thanks for easing my mind...especially since i don't have many 8 oz. jars. but now i have to disagree about mold being easily detectable. everything is, when there's enough of it . ever look at mold or fungus under a microscope ? there's a lot more than meets the eye ! i'd rather trust a vacuum seal.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Harvest Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here