In this article, we discuss the “Jone’s Rule of 86.” How it came into being, how you can use it to make Maple Syrup, and why it has been superceded by the “Jone’s Rule of 87.”
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Making Your Own Maple Syrup
For detailed instructions on how to tap maple trees, boil maple sap, and perform the maple syrup finishing boil, check out these articles:
Making Maple Syrup – Part 1 – How to Tap Maple Trees for Sap
Making Maple Syrup – Part 2 – How to Boil Maple Sap
Making Maple Syrup – Part 3 – How to Perfect the Finishing Boil
A simple and efficient method to get started making Maple Syrup is using an outdoor propane boiler (commonly called a ‘turkey fryer’).
The Jone’s Rule of 86
The Jone’s Rule of 86 is a simple equation that is used for determining how many gallons of Maple sap you will need to boil down in order to achieve 1 gallon of Maple Syrup.
This rule is named after Charles Howland Jones, a researcher at the University of Vermont who published a paper with J. L. Bradlee in 1933 called “The Carbohydrate Contents of the Maple Tree.” The details of which were made clear to me in an old publication called the Maple Sirup Producers Manual (Willits and Hills, 1938) on page 48.
The equation is as follows:
a = 86/X
where a represents the number of gallons of sap you will need to make 1 gallon of Maple Syrup, and X is the sugar content of your sap (expressed in %).
For example, if the sugar content of your sap is 2%, then the equation would look like this:
a = 86/2 = 43
You will need to boil down 43 gallons of sap in order to end up with 1 gallon of Maple Syrup.
What is the Sugar Content of Maple Sap?
The sugar content of maple sap is usually expressed in terms of °Brix, which is the % sugar content of an aqueous solution based on mass.
Sugar maple trees tend to have the highest sugar content, so often the ratio of sap to syrup for a sugar maple is on the order of 32:1 or so, at least in my experience. If you don’t mind ‘watery’ syrup, then you can get away with less boiling, so you end up with a higher yield, like 20:1.
| Type of Maple Tree | Sugar Conc. of Sap (%) | Ratio of Sap/Syrup |
|---|---|---|
| Sugar Maple | 4.5 | 19:1 |
| Red Maple | 4.1 | 21:1 |
| Amur Maple | 3.9 | 22:1 |
| Silver Maple | 3.4 | 26:1 |
| Box Elder | 2.5 | 35:1 |
What is the Sugar Content of Maple Syrup?
The sugar content of maple syrup is 66% by mass, and 87% by volume.
How do you Calculate the Sugar Content of Maple Sap From the Ratio of Sap to Syrup?
There seems to be a lot of confusion regarding how the ratio of sap-to-syrup can be used to determine the sugar content of your sap.
The confusion comes from the fact that Brix is a percentage of mass-to-mass, whereas Sugar Content is a percentage of mass-to-volume. Syrup at 66°Brix has 66 grams of sucrose in a 100 gram sample of syrup, but it has 87 grams of sucrose in 100 mL of syrup.
For small amounts of sugar in a solution (like sap), the Brix and Sugar Content are nearly the same. However, as the concentration of sugar increases, the Brix value and the Sugar Content values begin to diverge (see the graph below).
This table shows the Brix value and the corresponding Sugar Content % for lower Brix values (typical of sap, e.g. 3°Br)) as well as higher values (typical of syrup, e.g. 66°Br) (equation from wikipedia, sg values from Table 109, NBS Circular 440):
| Brix |
Grams of Sucrose per 100 mL of Syrup
|
| 0 | 0.0 |
| 1 | 1.0 |
| 2 | 2.0 |
| 3 | 3.0 |
| 4 | 4.1 |
| 5 | 5.1 |
| 10 | 10.4 |
| 15 | 15.9 |
| 40 | 47.1 |
| 60 | 77.2 |
| 64 | 83.9 |
| 65 | 85.6 |
| 66 | 87.3 |
| 67 | 89.0 |
| 68 | 90.8 |
| 69 | 92.6 |
Note that the sugar content by volume is about 87 for a Brix value of 66.
By the way, the “Rule of 86” applied back when the standard Brix value of Maple syrup was 65.5°Brix. Now that standard maple syrup is 66°Brix (66.9°Brix in some states), the value should now be the “Rule of 87.”
For sap, the percent of sugar (weight to volume) is small (typically 1-5%), so Brix and Percent of Sugar-to-Volume are nearly the same. Standard density maple syrup has a Brix value of 66°Brix, which corresponds to 87.2% solids as sugar.
The following table shows how many gallons of sap are required to make 1 gallon of syrup for various sap sugar concentrations.
| Sap Sugar Conc (%) | Ratio |
Gallons of Sap to Make 1 Gallon of Syrup
|
| 0.0 | – | – |
| 0.5 | 174:1 | 174 |
| 1.0 | 87:1 | 87 |
| 1.5 | 58:1 | 58 |
| 2.0 | 44:1 | 44 |
| 2.5 | 35:1 | 35 |
| 3.0 | 29:1 | 29 |
| 3.5 | 25:1 | 25 |
| 4.0 | 22:1 | 22 |
| 4.5 | 19:1 | 19 |
| 5.0 | 17:1 | 17 |
| 5.5 | 16:1 | 16 |
Conclusion
I hope you found this information helpful! For more information on Making Maple Syrup and to download my free 1-page PDF “How to Make Maple Syrup Cheat Sheet,” visit the Maple Syrup Homepage.
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Additional Articles in this Series on Maple Syrup Making!
These are the links to the other articles in this series:
- Easiest Way to Boil Sap for Maple Syrup
- 5 Reasons to Use a Propane Stove for Making Maple Syrup
- How to Use a Refractometer for Maple Syrup
- How to Perfect the Finishing Boil for Maple Syrup
- What is the Maillard Reaction in Maple Syrup?
- Frequently Asked Questions Related to Maple Syrup Making
- What is the “Jones Rule of 86?” And How Can I Use it to Make Maple Syrup?
- Free Maple Syrup Jar Labels (Printable PDF)
- “How to Make Maple Syrup Podcast!”
Detailed Picture Guides on How to Make Maple Syrup at Home
For detailed instructions on how to tap maple trees, boil maple sap, and perform the maple syrup finishing boil, check out these articles:
Making Maple Syrup – Part 1 – How to Tap Maple Trees for Sap
Making Maple Syrup – Part 2 – How to Boil Maple Sap
Making Maple Syrup – Part 3 – How to Perfect the Finishing Boil
Subscribe to the “How to Make Maple Syrup Podcast!”
Or listen to past episodes right from your browser:
Listen to the “How to Make Maple Syrup Podcast!“
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