Head space in Weck jars

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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.

Best Answer

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

  1. Full if you are processing fruits or vegetables that get topped up with a liquid like water or thin sugar syrup.
  2. At least 1 cm headspace for mushy goods like apple sauce.
  3. At least 4 cm headspace for anything that swells up (sausage meat).
  4. 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.

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