Head space in Weck jars

Question

I splurged and bought some Weck jars for canning.   I purchased the .5 liter tulip jars.   I notice that they have a substantially larger mouth than Ball/Kerr jars.  They also appear to be both fatter & shorter.   I tested with my canner, and can get only 5 jars per level instead of 6 jars with the Ball pint jars.
Does the difference in shape mean any changes I should adjust any recipes from the Ball Canning book?  I am particularly wondering if the head space should remain the same.

Stephie · Accepted Answer

I just checked the Weck (the manufacturer) website (German, sorry) and the recommended head space is

Full if you are processing fruits or vegetables that get topped up with a liquid like water or thin sugar syrup.
At least 1 cm headspace for mushy goods like apple sauce.
At least 4 cm headspace for anything that swells up (sausage meat).
Only half full for cakes etc. that get baked in the jars and then sealed.

The explanation by Weck for 1. is that all excess will just be pushed out during processing and that it won’t compromise the seal, anything with “particles” on the other hand could. Personally I always leave enough to be reasonably sure that nothing can get between the glass and the gasket, even for liquids - usually a generous half an inch or so for the use cases that fall under 1.

Timbo · Answer

I use the cylindrical jars from Weck and would say that the headroom can be kept the same in general. At the end of the day you just don't want any stuff to swell over and not have too little in there so it spoils.
In my experience keeping about a fingers worth of space to the rim will not cause you any major issues.

Head space in Weck jars

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