Transcript Measuring Food Quality with a Brix Meter (refractometer)

Measuring Food Quality with a
Brix Meter (refractometer)
April 17, 2008
Larry Howard
Bloomington Chapter
of the
Weston A. Price Foundation
Brix – What is it?
°Brix is the ratio of Total Soluble Solids (TSS)
to water in solution
25° Bx = 25% TSS by weight (e.g. 25 grams
of solids to 75 grams of water)
The “sap”or juice squeezed from the leaves of
plants contains mostly sugar molecules but
also smaller amounts of minerals, amino
acids, vitamins, plant hormones, and
proteins.
Brix – How is it measured?
A refractometer – a device with a prism,
a numeric scale and an eyepiece
a 2-3 drops of plant juice are squeezed
onto the prism and a demarcated line is
viewed on the scale
Why Brix?
Higher Brix – higher nutrient density
(assumption)
Higher Brix – better taste (widely
acknowledged)
Higher Brix – resistance to rotting
Higher Brix – resistance to disease
Higher Brix – resistance to frost
Higher Brix – Higher Quality!
(Useful Link:
http://www.tandjenterprises.com/brix_equals_quality.htm)
Variables
Plant hydration – a heat stressed plant,
hot windy conditions, or dehydrated
plant sample can affect results

dehydration of the plant or the sample
leads to false high readings
Temperature – calibration at 68° F

theoretically, higher temps  lower
reading, lower temp  higher reading
Experiments
Fruits/veg from different sources
Same produce, fresh vs. aged
Same plant, different times of day
Same plant, differing weather
conditions
Different plant varieties
“Skins-on” vs. Skins Off
Purchasing
~20$ -- 300$ and up
Google  Shopping  “Brix refractometer”
Technika -- ~$55
Features




scale – 0 – 30 Bx is desirable
digital vs. manual readout
auto temperature calibration, manual temp.
calibration or no calibration (must use a table)
Specs: accuracy (+/- %) and precision (1°, .1°,
etc.)
Sample Results
Earthbound Farm Organic baby carrots – 5
Grimmway Farms Organic whole carrots – 9
Tomorrow’s Organic Russet Potatoes – 7.5
Celery – 3
Lacto-fermented cucumber relish – 8
Oregon Tall Fescue – 9
Juice from supermarket orange – 11.2
Saturated salt solution at 69°F – 27.5
Social Hazards (tips)
Poor results are common – don’t despair
Work for improvement not perfection: from
poorfairgoodvery goodexcellent
Careful when assessing other’s
products/gardens!
Offer to pay for samples, explain yourself,
right to refuse (“I’m looking for a higher
sugar content”)
Brix Chart (partial)
from International Ag Labs, originally produced by Dr. Carey Reams