Food Preservation Gives Pleasure When Heross Jar Caps are Chosen!

Providing you follow our advice, we can ensure that jar sealing is easy, convenient and safe. Here are some tips as follows:

Before sealing the jar, clean its brim, check it for any unevenness or jaggedness. Then, fill the jar up to the supporting edge.
Jar sealing can be done with some automated equipment (sealer) or by hand. It is of significant importance for you to regulate the force applied onto the cap, when sealing. There should be enough force applied to ensure hermetical sealing and thus prevent any potential opening. On the other hand, the force applied to the cap when sealing should not be excessive as other problems may arise like difficulties for the user to open the jar or cap re-opening due to deformation of the cogs. If you seal the jar by hand, then we recommend wetting your hands beforehand. On condition that your hands are wet, the force you apply while sealing the jar will be sufficient to achieve hermetical sealing.
The jar caps are fitted following the cap screws of the jar. The grade of the screw line ensures smooth screwing of the cap with little effort as well as relatively short motion of the cogs along the screws in order to achieve proper closing reinforced with a seal between the cap and the jar. Jar closing is based on the principle of transmitting initial pressure onto the cap. Then, due to elasticity of the grommet and further screwing, the jar mouth fits in it.


1.1. Examine the brim of the jar for any unevenness or jaggedness.
2.Clean up thoroughly the brim of the jar.
3.Do not fill the jar above the supporting edge.
4.Wet your hands before you start sealing the jars.
5.Screw the cap following the cap screws.
6.Do not press the cap excessively when sealing the jar, otherwise you may deform the cogs leading to re-opening of the jar.

The following rules are recommended to observe:

1.Jar filling – up to 96% of the jar volume. You should leave some space, about 4%, or fill the jar up to the supporting edge so that vacuum can be created.
2. 2. Jar sealing – if possible, dip the cap into hot water. When the cap is heated up, the grommet softens and thus, the sealing is more effective. Adjust the cap to the jar screws and then screw the cap so that the cogs slide along the screw line. To create vacuum in a hermetically sealed jar, apply some physical force. Make sure you have not tightened the cap excessively, otherwise you will not be able to remove the air from the jar and create vacuum.