Testing Quality of Produce

An Easy Way to Measure the Quality of Your Food An obvious way to measure the quality of food is to send a sample to a lab for analysis. That could generate a lot of interesting information. But, what if you wanted to know how good a fruit or vegetable is right now? What if you wanted a cheaper and easier way to test a large variety of produce?

There’s a simple at-home method that almost anyone can use to get a general idea of the quality of a fruit or vegetable.  The only instrument required is a refractometer.

Pictured above is a refractometer. It’s a simple little gadget that measures dissolved solids (in basic terms: mostly sugars and minerals) in plant juice / sap. In general, the higher the dissolved solids in the sap, the higher the quality of the produce.

The way it works: a drop of plant juice is applied to the plate. Here, a few drops of juice from an onion are squeezed out with a garlic press.

Squeezing onion juice onto the refractometer

squeezing onion juice onto the refractometer (2)

Then, you hold the refractometer up to the light and look through the eyepiece. A reading will show on a scale that gives the percentage of dissolved solids (technically, degrees Brix).

It looks something like this:

onion juice 7 brix (2)

This shows a Brix reading of 7, which is between Average and Good on the Brix chart.

The higher the content of sugars and minerals in the sap, the higher the reading will be (that is, higher Brix). The higher the Brix reading, the better the flavour of the fruit or vegetable will be.

There are established Brix ranges for many types of fruits and vegetables. Here is a post with more information on Brix readings, and a chart showing the ranges of Brix readings for common fruits and vegetables.

Dr. Carey Reams was the first to intensively use the Brix scale in large-scale agriculture. He was working in Florida with high-value food crops, and the goal was to improve the flavour of the crops. They were looking for better ways to fertilize the crops (to improve the flavour and quality of the crops), and found out that what was used to fertilize the crop directly affected the Brix readings of the plant sap.

He developed a system of fertilization and farming practices that produced higher Brix crops. Through extensive laboratory study, it was found that high Brix foods contained more nutrients (minerals, carbohydrates, proteins, fats). Through many taste tests (no labs needed for that!) it was very obvious that high Brix foods also contained more flavour.

Most fertilizer programs are meant to increase the yield (quantity) of the crop. I like the biological / regenerative approach because the focus is on increasing the quality of the crop, and the side benefit is getting good yields.

Once you test a few samples of fruits and vegetables with a refractometer, you will be hooked! This gives an easy way to test fruits and vegetables at home, and evaluate various sources of food to find the best.