5/16 gravity?! Surprising experiment in a sugar bush in Estrie

(Video below)

Alan Isabel, representative of LS Bilodeau and installer of tubing networks, reflects on a job done in 2020 in a sugar bush in Estrie. What is unique about this installation is that it is gravity-fed on 5/16 tubing. Usually, gravity systems are mainly installed on 3/16 tubing because it is generally considered better suited for gravity systems. Due to its 30% smaller diameter than 5/16 tubing, it prevents water and air from separating during smaller flows (which would result in losing vacuum) and allows for more natural vacuum. Finally, since the water is confined to a smaller diameter, it spreads over a longer length, in other words, it travels a greater distance than if it were spread over a larger diameter.

The Context

The couple of maple producers who own this property purchased the plot of land 5 years ago and discovered its maple potential only after starting their forestry management. Initially, the land was intended for forest walks and as a playground for their semi-retirement. Realizing the maple potential, the couple decided to turn it into a small family project in the coming spring and acquired one of our Gentleman Farmers. They tapped about 75 trees with buckets and set up under a temporary shelter to start boiling.

That was enough for the novice maple producers to immediately be afflicted by spring fever.

As you know, spring fever is an incurable disease that manifests itself every year with an insatiable desire to tap more and constantly improve one's setup. In just a few years, they turned these 17 acres into an exceptional maple grove with nearly 500 taps today. The maple producers also cultivate fruits, mushrooms, and vegetables during the summer. They built a beautiful sugar shack and turned this property into a real gem nestled in the heart of the Eastern Townships.

Installing the Tubing

At first, the couple wanted to preserve the wild appearance of the forest and was not interested in installing permanent tubing. However, after a crazy sap flow year in 2019, they concluded that a tubing system would greatly ease their task and make their sugaring time much more enjoyable. They decided to keep a few buckets, to which they planned to install a tubing system that would flow into collection tanks at 2 collection points. They specifically wanted a smoky tubing, and given the production lead times and the approaching sugaring season, we opted for an installation doubled with a double Guzzler diaphragm pump to meet the clients' wishes. We also installed a vacuum gauge at the end of each line to monitor the vacuum levels and facilitate system sealing each year. When spring came, that's when we made this surprising discovery: the use of the vacuum pump was not necessary; the vacuum was created without resorting to the Guzzler pump.

Gravity on the 5/16, yes, under certain conditions

What we decided to do at that time was simply to add more taps per line, about 60 taps per 5/16 line to ensure an sufficient water flow at all times. For comparison, on a 3/16 tubing line, there are generally 30 to 40 taps per line. Among the advantages of the 5/16, we observed that it tended to clog less easily (ice, wood debris, yeast) than the 3/16. Since it is smoky in color, it also thaws more quickly in the morning as it absorbs more heat. However, this experience may not be suitable in every situation as it is estimated that at least a 5% slope is needed, otherwise the use of the pump would be necessary to generate enough vacuum. In summary, for a gravity-fed installation on the 5/16, you will need to meet these 3 points:

• Maintain a watertight network (see our 2 articles on the subject: Leaks-Part 1 - Leaks-Part 2);
• Have sufficient slope to generate natural vacuum (minimum 5% slope);
• Have enough taps on each line (in our experience: 50 to 60).

Results

At first, the couple wanted to preserve the wild appearance of the forest and was not interested in installing permanent tubing. However, after a crazy sap flow year in 2019, they concluded that a tubing system would greatly ease their task and make their sugaring time much more enjoyable. They decided to keep a few buckets, to which they planned to install a tubing system that would flow into collection tanks at 2 collection points. They specifically wanted a smoky tubing, and given the production lead times and the approaching sugaring season, we opted for an installation doubled with a double Guzzler diaphragm pump to meet the clients' wishes. We also installed a vacuum gauge at the end of each line to monitor the vacuum levels and facilitate system sealing each year. When spring came, that's when we made this surprising discovery: the use of the vacuum pump was not necessary; the vacuum was created without resorting to the Guzzler pump.