Demonick's Cigar Pages

The Great Silica Gel Humidor Study

Bottom line:

• Use Ultra Pet Crystal Clear Littler Pearls (Regular Density Silica Gel (RDSG))
• Dry the silica gel at 325F for 4 hours
• With the dried kitter litter above, use 0.053 grams per cubic inch, or 91 grams per cubic foot, or 3.05 grams per quart of humidor capacity.
• Condition silica gel with distilled water as follows:
  • For 60% RH use 10.0% of the dry weight of the silica gel
  • For 65% RH use 12.5% of the dry weight of the silica gel
  • for 70% RH use 15.0% of the dry weight of the silica gel

One may wish to start a couple of % less water and add as needed in the actual application. Use the silica gel in the humidor in as thin a layer as possible. Dry silica gel kitter litter in a THIN layer for 4 hours at 325F.

The data plot shows 1 gram of water in 20 grams of silica gel moved the %RH equilibrium 8 points from 61 to 69. That is, 0.00625 of the total weight of silica was used to move the %RH equilibrium point 1% within the range 61-69.

Example: I have 200 grams of conditioned silica gel in a 64 quart cooler. Let's say the cooler is holding 62% RH and I would like to get it to 66%, i.e., raise it 4%. 200 grams x 0.00625 x 4 = 5.0 grams of water.

1 gram of water equals 1 ml equals 1 cc. Use a syringe to "weigh" the water. Use distilled.

The Gory Details