Generally my headspace comes out fairly near what it was originally and with jams it's almost exactly the same so I would agree it sounds like there's a problem.

Headspace can increase during processing if the jars are overpacked (i.e. too many solids not enough liquid) and the product in the jars swelled and absorbed some of that liquid, resulting in a drier mixture.

With jam I'd guess too vigorous a boil or fluctuations in temperature are likely culprits. Siphoning is also a possibility but you'd see that in the water. It's less likely with jam but certainly possible with, say, peaches or tomatoes.

Carol

How can you tell what is going to happen before it happens?

How can you tell what is going to happen before it happens?

Sorry I don't understand the question.

_________

Generally my headspace comes out fairly near what it was originally and with jams it's almost exactly the same so I would agree it sounds like there's a problem.

Agree with Carol. No noticeable difference in headspace before and after processing here either with jams and such. How long do you process your jams/jellies?

With many other foods then all the issues she mentioned - boil over, siphoning, over-packed jars, wrong ratio of solids to liquids, etc. can come into play. But the goal is to eliminate those issues so that headspace doesn't fall off. It can be prevented.

Dave

I find that it cannot be prevented when making pickled okra. Due to the nature of the hollow vegetable that has been pierced, no matter how full of brine I put in the jar, nor how long it sits and is pressed with a spoon to make the bubbles rise before I put it in the BWB, when cooled it is at least an inch below the rim, sometimes more.
Nancy

I guess I didn't really give the question I wanted answered. Was last year's fair judge too harsh when she downgraded canned goods if the headspace was more that 1/4" greater than the recommendations? Apparently a lot of people were upset with their red ribbons instead of their usual blue ribbons.

I canned tomatoes today. I was very careful to remove air bubbles, measure headspace, leave jars in BWB without heat for 5 min before removing from kettle. There was no food or color in the canner water. I measured the headspace of 4 qt standard mouth jars about 15 min after they came out. None of the jars contained still boiling liquid. All the lids had popped down (love that sound!) One jar measured 1/2", one 5/8" and two were 3/4". Now it is 6 hrs later, the jars are completely cooled and they all measure approx 1" headspace. I guess I believe the liquids contracted as they cooled, giving me more headspace than when I started.

This led to a very lively discussion at dinner tonight. Possible theories included our elevation of 2000', but no one could explain what that impact might be. Then it was pointed out that plant cells have vacuoles containing air or CO2. These vacuoles could rupture during the canning, releasing the gas and causing the tomatoes to compact a bit.

Anyway, since this is a small community fair and not the county or state fairs, I will be more lenient than last year's judge. I guess I've answered my own question. I'll still focus on safety and disallow improperly canned items. I've had to deal with very irate people when I disallowed dishwasher canned foods. At least nowadays I can refer people to appropriate websites for canning info.

It's not unusual for judges to be meticulous about headspace and I have seen Ball-sponsored competitions where that is a big issue.

I should have mentioned that some packs are more susceptible to increase of headspace. For example, hot-packed product is more "stable" than raw-pack and generally the headspace doesn't change much.

Carol

JMO but is sounds to me as if she - the past judge - may have just focused too much on one factor where it should be over all presentation.

If a jar was of questionable presentation in other ways and also down in headspace, fine, poor grade. But if it is a quality presentation in all other ways and only off by 1/4" headspace I can't see failing it.

So my question is what are all the factors besides headspace you should look at?

Dave

Each jar must include the date it was prcoessed, method (BWB or pressure), how long, recipe source. If from USDA or Ball Blue Book, we accept it, otherwise list of ingredients and amounts along with source of the recipe.
Typically, I judge based on the above, uniformity of size and color. I have a copy of the Judging Home Prepared Foods by NCHFP on my laptop for quick and easy reference. Wi-Fi access in town isn't good. It's a metal building with large hills surrounding town.

otherwise list of ingredients and amounts along with source of the recipe.

So they are allowed to enter personal, untested recipes and you have to evaluate those recipes for safety too? That would be difficult I think.

Sure most high acid fruit recipes would 'probably' be safe but there are low-acid fruits too that some make preserves out of, the vegetable based things like hot pepper jelly, and there is the windfall fruit rule that require extra acid, and then I have seen some strange recipes like the pumpkin-pepper recipe discussed in another thread here.

I sure don't envy you the job. Good luck with it.

Dave

Good point. No, by source, I meant Ball pectin box, Sure-gel, Cooperative Ext bulletin, etc. If it's Aunt Lil's recipe, it will get disqualified. If it's something unusual, I'll try to do a quick online search if I can get online.