Calibrating your humidor

Requirements:

• Salt
• See through ziplock bag or plastic container
• Small cap, like a bottle top
• A couple of drops of water

Directions:
Put a teaspoon of salt in the cap and add a couple of drops of water, enough to dampen, like wet sand (not a puddle). Place your hygrometer in the bag or plastic container, together with the cap, taking care not to spill it. Seal the bag or container with some air in it. Leave for at least 6 hours to stabilise. Read the hygrometer it should read 75%. If not use a small screw driver to turn the small screw on the back of the hygrometer until it reads 75%.
Should your hygrometer not have this adjustment then you can remember any deviation and adjust accordingly, for example, if it reads 80% then you will need to subtract 5% from any future reading.