Buddy Syrup

What is buddy syrup?

Buddy maple syrup is the bane of many a maple syrup producer. Its taste has been described as “malty”, “peppery”, “cabbage-like”, and “like expired orange juice”, which is difficult to market to consumers. Its appearance usually signals the end of the maple season.

Sap that has gone buddy sometimes looks, smells, and tastes just like regular sap, and only becomes obvious after the sap has been boiled down. Each year, producers are collectively left with thousands of litres of product that they can’t sell.

What causes it?

Buddy syrup got its name because its appearance coincides with the lead-up to bud break in maple trees, usually when buds are beginning to swell or by the time buds visibly start to lengthen. Over the course of the season, certain chemical compounds build up and peak before leaf emergence. Researchers think that one or more of these compounds are the reason for buddy flavour – organic sulfur and microbial activity are two possible culprits. The buddy flavour is likely triggered by how one of these compounds changes during boiling.

Officially, bud break is used to describe the stage when leaf tips are barely visible. However, buddy will already have appeared by the time your buds look like the photo below.

A sugar maple bud that is almost entirely green, with small leaves peeking out from the tip.
Sugar maple bud break stage, with leaf tips barely visible. Note that buddy will have appeared by this stage. Photo from the University of Vermont’s Maple Bud Field Guide.

How to “read” your tree buds

Looking at the buds on your trees can give you an indication of how far off buddy is. Dormant buds are generally still good. Buddy syrup can appear as soon as the buds begin swelling, and the farther along your buds are, the more likely buddy is to appear. The outline below is for sugar maple.

Four photos of sugar maple buds in a progression of development. A pencil and a ruler are provided for scale; the maple bud starts out the size of the graphite pencil tip and grows to twice the size by the last photo. An arrow under the photos says "good sap" under the small bud and "buddy sap" between the second and third photos.

If I have it, how do I get rid of it?

Before 2020, there has been no way to get rid of the buddy flavour in finished maple syrup. However, researchers at Centre ACER in Québec may have found a method. Before attempting it, remember that this is still new research and there is no guarantee that it will work for you. Make sure to try it on a small scale, such as in a 5L quantity, before expending too much time, fuel, and resources.

Here are the instructions if you’d like to try it for yourself:

  • Boil 5L of buddy maple syrup for 2 hours at 104.5°C
  • Continually add ultrapure or RO permeate water at a rate of approximately 76mL/minute to keep the boiling point and syrup concentration constant. It is better to maintain syrup at slightly higher Brix (above 66 but below 68.9) to prevent mould formation.
  • Taste the syrup at the 60-minute mark; syrups with less buddy flavour may not need the full 2-hour treatment
  • Store syrup for 12 months before re-taste-testing, in case the buddy flavour compounds re-form

Remember that there is no guarantee that it this method will work for you. However, I would be interested to hear any results – feel free to get in touch with reports (jenny.liu2@ontario.ca).

If I don’t want it at all, how do I avoid it?

For years, farmers have relied on nature’s signs of spring to tell them when trees are ready to break bud. Some growers listen for frogs or woodcocks, while others look at how tall wild leeks are.

However, the best way is to smell, taste, and stir your sap:

  1. Smell and taste the sap – any smells and tastes that are not normal for you will likely boil down into syrup that is not normal
  2. Stir the sap – it will let you observe the texture for ropiness
  3. If the sap passes all smell, taste, and stir tests but you still want to make sure, then boil a small amount on a stove.
  4. After the sap has reduced by approximately half, smell it for any off-notes
  5. Taste concentrated sap for any off-notes after it has cooled

Future Directions

Researchers at Fanshawe College and Carleton University are also currently working on a more reliable method, where growers could simply take some sap from the tree and perform an in-field test for the chemical compounds causing the buddy flavour. They can then stop tapping immediately.


Camara, M., Cournoyer, M., Sadiki, M., & Martin, N. (2019). Characterization and Removal of Buddy Off‐Flavor in Maple Syrup. Journal of Food Science84(6), 1538-1546. https://onlinelibrary.wiley.com/doi/abs/10.1111/1750-3841.14618

N’guyen, Guillaume Quang, et al. “A systems biology approach to explore the impact of maple tree dormancy release on sap variation and maple syrup quality.” Scientific Reports 8.1 (2018): 1-13. https://www.nature.com/articles/s41598-018-32940-y

Skinner, M., and Parker, B. L. (1994). Field guide for monitoring sugar maple bud development. Vt. Agric. Exp. Stn. RR 70 and VMC RR 8, Univ. of Vt., Burlington. 31 pp. https://www.uvm.edu/~entlab/Publications/MapleBudFieldGuide.pdf