The Brix Barometer

Brix measures the light refracting through dissolved sugars with the use of a portable refractometer – showing nutrient density levels of the plant, based on the presence of a diversity of simple & complex sugars.

The Brix Barometer is a combined metric, examining the difference between the brix reading of weeds on your farm, with the brix of your crop (vines). If your weeds are more successful than your vines, this indicates your soil needs some support!

What to record

Brix reading of weed (0-30 on refractometer)

Brix reading of crop – vine (0-30 on refractometer)

Note: is the line is fuzzy or clear?

Record a photo for reference


Refractometer (0-32%)

Heavy duty Garlic Crusher

Water Squirt Bottle (optional)

Dry cloth/kitchen roll

How to do the test

1. This test can be done alongside the basal ground cover transect. Moving along approximately the first 10m of your transect away from a sample site, collect a handful of plant material by tearing – like a cow or a sheep munching at the plants.

N.B: Do not sample diseased, insect attacked or stressed plants.

2. Collect two separate measurements for ‘Brix of crop (%)’, and ‘Brix of weed (%)’ in Sectormentor – you’ll be examining the difference between these two readings.

3. Squish the handful of material into the garlic crusher.

4. Hold refractometer in one hand, flip back the plastic flap to expose the glass face.

5. Hold filled garlic crusher in the other and squeeze ‘juice’ from picked grasses onto the glass face of the refractometer.

6. You need just one drop of ‘juice’ on the glass screen. Then drop the refractometer’s plastic flap on top of the drop so it smears across the screen.

7. Hold the refractometer up to the sky (about 15degs) and look into the lens.

8. There will be an area/line on the scale where it changes from light blue below to dark blue above.

9. Record the number on the scale and make a note of whether the line is fuzzy or not in the notes section.

10. Clean and dry the glass screen with your water ready for the next test

11. Remove residues from garlic crusher


Integrity Soils – The Use of Refractometers