Calculating Extract Concentration

Written by
Hiwassee Products
Published on
January 1, 2025 at 3:54:00 PM PST January 1, 2025 at 3:54:00 PM PSTst, January 1, 2025 at 3:54:00 PM PST

The bulk density of compost can vary due to moisture and other factors. In order to calculate your extract concentration in lb/gal:

  1. Weigh out 10 lbs of compost into the hopper.
  2. Open valve to extractor and ensure the water agitation is running. Figure 7b: Turn on booster pump if present.
  3. If using the X250 or X350, set auger speed to 4 and start the auger. If using the X150, turn the auger and count rotations per minute. We recommend 6-8 RPM for most composts.
  4. Time how long it takes for 10 lbs of material to run out of the hopper at a given RPM.
  5. Multiply the flow rate (8.5 GPM at 40 psi for X150 and X250, 12 GPM for the X350) by the time it takes to run 10 lbs of compost. This gives you the total gallons of extract produced. Then divide 10 lbs by this number to find your extract concentration in lb/gal.
  6. Repeat at different RPMs to arrive at your desired extract concentration.