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University of Illinois Extension

Filling Jars

Headspace

Headspace illustration

Too Little Headspace?

  • Food may bubble out during processing.
  • Food deposited on rim may prevent proper sealing.

Too Much Headspace?

  • Food at the top is likely to discolor.
  • Jar may not seal properly, because not all air may be forced from jar.

Screw on Lids

  • Use new two-piece lids
  • Wash lids and screw bands in hot soapy water and rinse
  • Heat lids in hot water; follow manufacturer’s direction
  • Position the treated/heated lid on clean jar rims
  • Screw the band down fingertip tight
    • Not too tight. Do not use force. Note: tightening screw band too tight may result in buckled lids that may not seal properly.