How to Use a Maple Syrup Hydrometer (2024)

If you are producing maple syrup for home consumption, the exact sugar content of your product may be primarily a matter of taste. If you plan to sell any, however, many states have very precise requirements. This is where a hydrometer comes in.

A hydrometer measures the density of the maple syrup. The denser maple syrup is, the more sugar it contains. The sugar percentage of the liquid is measured in degrees Brix, where one degree Brix equals 1% sugar content. The standard density for maple syrup is 66.9 Brix.

A hydrometer looks a bit like an oversized thermometer and is calibrated to measure cold syrup at 60°F or hot syrup at 211°F or higher. At Bascom, we offer both short and long hydrometers and matching test cups. The long hydrometers offer a greater level of detail, measuring 51-71 °Brix in increments of .2°Brix, while the short hydrometers measure a wider range from 45-75 °Brix but in .5 °Brix increments.

Using a clean, undamaged hydrometer, follow these general steps to test your syrup:

1. When the syrup reaches a boiling temperature 7.10°F above the boiling temperature of water (which varies according to elevation), you are ready to test for proper density.

2. Hold the test cup upright. Fill the test cup up to ½” to ¾” from the top with hot syrup to be tested. DO NOT HAVE THE HYDROMETER IN THE CUP.

3. It is important to take a temperature reading at the same time as the hydrometer reading because density changes with temperature. Without letting the syrup cool, place the cup on a level surface and immerse a thermometer. Slowly immerse the hydrometer into the syrup into the test cup until it reaches the “HOT” test mark and then carefully release it.

4. Read the temperature from the thermometer and the Brix number from the hydrometer. 211°F is the average temperature of syrup when measured immediately after draw-off from the evaporator. At this temperature, the syrup is at the proper concentration when the reading line is at the Hot Test line marked on the hydrometer. If the Hot Test Line is below the reading line of the liquid, continue to boil since the syrup’s sugar concentration is too low. If the Hot Test Line is above the reading line of the liquid, the syrup is “heavy” and should be diluted with sap. For other temperatures, please consult the chart:

   Temperature ℉	Degrees Brix
   209	59.0
   202	59.6
   193	60.0
   185	60.4
   176	60.9
   167	61.4
   158	61.8
   149	62.3
   140	62.8
   130	63.3
   120	63.8
   110	64.3
   100	64.3
   90	65.4
   80	65.9
   70	66.4
   60	66.9
   50	65.4

   Bix reduction required	Fluid oz of sap / gallon
   0.5	1.26
   1.0	2.52
   1.5	3.80
   2.0	5.08
   2.5	6.38
   3.0	7.68
   3.5	8.99
   4.0	10.32

   If the reading is lower than the number on the table, the syrup is “light” and will need more boiling. If it is higher, it will need to be diluted. Here is the quantity of sap you need to add to bring back a gallon of syrup:

   Heavy syrup (over 66.9° Brix) forms crystals at the bottom of the container, while light syrup (under 66.9° Brix) can spoil and develop mold.
   After reading the hydrometer, be sure to remove it from the test cup and rinse it with hot water. During the boiling period, store the hydrometer in a container of clean, hot water or hot sap.

   Questions? Please give us a call at (603) 835-6361 Monday through Friday from 7:30 am – 4:30 pm EST and Saturday 8 am – 12 pm EST.