Using Brix Testing as a Farm Management Tool

Testing Brix levels in your pasture, fruits and vegetables is a handy tool for not only giving you a quality assessment but as a management tool for assessing your practices. So, what is Brix?

Adolf Brix was a German chemist in the 1800’s who first figured out how to measure the density of plant juices by floating a hydrometer in them. This was of great value to wine growers as they could then figure out which grapes would make the best wine.

Brix is traditionally thought of as the measure of sucrose, but it is actually the percent solids (TSS) in a given weight of plant juice, nothing more, nothing less. So, it is a sum of the pounds of sucrose, fructose, vitamins, minerals, amino acids, proteins, hormones, and other solids in one hundred pounds of any particular plant juice. In other words, it tells you how nutritious a particular plant is as well as how healthy the plant is, the higher the Brix the better!

A refractometer is an optical device that measures light passing through a liquid where it bends or refracts. Thicker, more dense, liquids refract more. Solids dissolved in a liquid give a refractive index in direct relation to the amount of solids. Refraction is extremely exact.

Here at Chaos Springs, we started measuring Brix in 2003. The farm had been a small dairy unit for about 50 years and was very run down. The Brix in the pastures at that time were 2 to 3. As we implemented an organic, biological, regenerative program, which started with compost teas, we gradually saw the Brix levels rise. Today our pasture Brix levels are consistently over 10 and have risen to 18 at times.

In addition to giving you a general idea of the health of your plants you can also determine the effectiveness of your fertilizer or nutrient program. If you take a Brix reading before application and then again an hour or so after application your Brix level should rise 2-5 points. This tells you the application you made did some good. This works well with liquid application but will take longer with dry fertilizer application. In the next 24 hours to a couple of days the Brix may drop again, but repeated applications should see a consistent rise over time.

There are a number of opinions on how to go about taking Brix readings. For pasture some people like to roll the grass in their hand to get the juices from the plant, some prefer to just squeeze the juice without rolling. The method for fruits and vegetables will depend on how much free moisture there is, tomatoes will be easier than carrots. The important thing is to be consistent with your method.

Below is a chart that gives an idea of good Brix levels for different crops. Have a look and see you are doing.