1. Why Do Buyers Have to “Deduct for Moisture”?

The primary reasons why buyers cannot purchase yields with high moisture content at full price are based on these major facts:

  • We sell “crop substance,” not “water”: Freshly harvested yields have high moisture content (25-30%), which means a portion of the weight is actually water.
  • Moist crops cannot be stored: If the moisture content is not reduced, the crops will generate heat, mold, and rot immediately.

2. What is the Standard Moisture Level?

Generally, the appropriate moisture content for each type of crop varies. For instance, the standard moisture content for paddy and maize is at 13-15%. [cite: 54]

  • 15%: Standard full price. [cite: 54]
  • Above 15%: Subject to weight deductions. [cite: 54]
  • Below 15%: (Dry yield) May receive an additional price premium. [cite: 54]

3. Calculation Method: How Much Money Disappears?

The international standard formula commonly used is: [cite: 55]

“For every 1% of excess moisture, 1.5% of the weight will be deducted.”

Real Calculation Example

Suppose you sell 1 ton (1,000 kg) of Jasmine rice. The signboard price is 12,000 Baht/ton, but the measured moisture content is 25%.

Step 1: Find the excess moisture content 25% (measured) - 15% (standard) = 10% excess

Step 2: Calculate the deducted weight (Formula: x1.5) 10% x 1.5 = 15% weight deduction
Calculated as weight: 1,000 kg x 15% = 150 kilograms [cite: 56, 57]

Step 3: Summary of total money to be received Actual remaining weight for sale: 1,000 - 150 = 850 kg.
Money received: 850 kg x 12 Baht = 10,200 Baht

⚠️ Summary: 1,800 Baht per ton disappears instantly! [cite: 58]

4. How to Minimize Deductions?

  1. Harvest at the yellowish-green stage: Do not harvest yields that are too fresh. During the golden grain period when the tips of the panicles begin to curve down, the moisture content will be around 20-24%. [cite: 59]
  2. Drain the water before harvesting: Drain the water out of the field 7-10 days prior to harvesting to help reduce the moisture content within the grains. [cite: 59]
  3. Dry the crops yourself: If you have a drying yard, reducing the moisture content to 15% by yourself will allow you to obtain the full market price. [cite: 59]