timmeh87
03-11-2013, 10:16 PM
I had some syrup come out a little thin, so I set out to measure the specific gravity of the cold syrup to see if I should heat it up again. I found out that maple syrup hydrometers are ridiculously expensive, so I had to come up with an alternative. All you need is a kitchen scale (Preferably digital, or an accurate balance scale) that is accurate to the gram, and about a liter of the liquid you are measuring. The more liquid, the more accurate this method is.
1. Clean and dry a jar or measuring cup that can hold about a liter of water. (It can be anything, but its good if it has a fill line marked near the top)
2. Weigh the empty jar to the nearest gram and record this number.
3. Fill the container exactly to the fill line with cold water, record the weight. (Water warmer than 10 degrees C (50F) starts to get much less dense, and it will throw the numbers off a bit.)
4. Empty and dry the container. Now fill it to EXACTLY the same level with the liquid being tested and record the weight.
5. Let the weight of the jar be "J", the weight of the jar with water be "W", and the weight of the jar with mystery liquid be "L". The specific gravity is
(L - J) / (W - J)
(L - J) is just the volume of the liquid in mL, but it is better to measure this number exactly rather than rely on any printed markings. The formula is simply taking the weight of the mystery liquid and dividing it by the weight of the same volume of pure cold water, which has a specific gravity of exactly 1.
And remember, the temperature still counts. As sap cools in a jar, the liquid level will go down noticeably as it cools. If you use hot syrup, do the weighing as soon as you have filled it to the line.
I tested the method on my reboiled syrup and got a density of around 1.36. Its as thick as my store bought reference syrup now, so I am happy, I'd do this test on the reference sample, but Ill leave that as an exercise for the reader, gotta get back to boiling...
1. Clean and dry a jar or measuring cup that can hold about a liter of water. (It can be anything, but its good if it has a fill line marked near the top)
2. Weigh the empty jar to the nearest gram and record this number.
3. Fill the container exactly to the fill line with cold water, record the weight. (Water warmer than 10 degrees C (50F) starts to get much less dense, and it will throw the numbers off a bit.)
4. Empty and dry the container. Now fill it to EXACTLY the same level with the liquid being tested and record the weight.
5. Let the weight of the jar be "J", the weight of the jar with water be "W", and the weight of the jar with mystery liquid be "L". The specific gravity is
(L - J) / (W - J)
(L - J) is just the volume of the liquid in mL, but it is better to measure this number exactly rather than rely on any printed markings. The formula is simply taking the weight of the mystery liquid and dividing it by the weight of the same volume of pure cold water, which has a specific gravity of exactly 1.
And remember, the temperature still counts. As sap cools in a jar, the liquid level will go down noticeably as it cools. If you use hot syrup, do the weighing as soon as you have filled it to the line.
I tested the method on my reboiled syrup and got a density of around 1.36. Its as thick as my store bought reference syrup now, so I am happy, I'd do this test on the reference sample, but Ill leave that as an exercise for the reader, gotta get back to boiling...