The task of cleaning everything up is a big job, but it will be easier the sooner it is done after harvest. Where sugary residue is left too long on surfaces, it can harden into a cement-like layer and become very difficult to remove. Maple equipment dealers have cleaning and sanitizing products that are designed specifically for maple equipment.
To ensure safe and clean summer storage, it is important to both clean and sanitize tubing.
Step 1: Clean
Flush the sap tubing with potable water as soon as possible after the season. During the late stages of harvest, the inner surface of sap collection tubing becomes covered in a bio-film layer of sticky sweet residue, bacteria, yeast and mould. If left to sit as spring temperatures begin to warm, the collection of organisms inside the tubing can quickly fill the inner tube walls with mould.
This residue can be removed using several methods.
Sap can be removed by leaving the vacuum turned on while pulling taps from trees, which draws residue away from the small lateral tubes towards larger mainlines.
Keep your vacuum on and dip each drop line into a bucket of potable water to rinse out drop lines and lateral tubing. Cap each line or spout as you go.
Work your way towards the sugar house, keeping everything “behind” you clean. You may use pliers to prevent backflow.
Another washing method is to pump potable water from the bottom mainlines upwards into the sugar bush tube network to rinse remnant sap and biofilm out of the tubes. One mainline and its lateral tubing system is washed at a time in sequence. Check-valve spiles will not work with this washing method unless check-valves are equipped with adapter fittings onto drop lines.
A drawback to this washing method is that biofilm residue can be blown through spiles into the tap holes, which may not be ideal for healing of tap holes. Old tap holes need to be kept dry and hopefully not loaded with sugar, where wood decay organisms can fester in summer until trees heal the tap holes.
Cylinder-shaped sponges that are sized according to tube diameter are available for mainline cleaning. These sponges are moistened and then inserted into the far end of a mainline where the sponge is pulled by vacuum down the line to squeegee the biofilm from the inner walls. The sponges usually (hopefully) reappear downstream in the sap extractor tank.
Step 2: Sanitize
Sanitizers are chemical products that disinfect surfaces that have been previously cleaned. Sanitizing is an important step in preventing mould growth, and can also extend the life of your tubing.
Canadian syrup producers use several different sanitizers, including bleach, oxisan, and 70% isopropyl alcohol (IPA). The most common is IPA. Beware if using bleach, as it contains salt that is very attractive to squirrels.
Sanitizers are common to all modern food processing industries and must be approved for use in Canada by the Canadian Food Inspection Agency and Health Canada. Maple industry research scientists both in Canada and the United States test various methods of cleaning maple sap tubing and the efficacy of various sanitizing products.
Many maple equipment dealers can provide federally approved sanitizers for use in maple sap tubing. Producers can request printed information from dealers showing proof the sanitizer is a federally accepted product. Federal food inspectors may request to see this documentation from producers during inspections.
Federal registration of sanitizers and pest control products is similar between Canada and the United States, but is not usually synchronized. Sanitizers that are approved for use in Canadian maple production may not be approved for use in the States, and vice versa. This lack of synchronization does not restrict trade of food between countries, as long as producers within each country follow their own established regulations.
Maple syrup producers in Canada and in the United States can verify with their own provincial or state regulatory agency of approved sanitizers and other pest control products.
How to Use IPA
Once clean, many producers currently use isopropyl alcohol as an effective sap line sanitizer. Isopropyl alcohol is federally registered for use in Canada as a sap tube sanitizer, but is not currently approved for use in maple sap tubing in the United States.
Canadian maple equipment dealers can provide approved formulations of isopropyl alcohol for use in maple sap tubing. There are IPA products that are not approved for use on food contact surfaces, therefore, contact a Canadian maple equipment dealer.
Important: The objective is to allow gaseous vapour of isopropyl alcohol to fill the tubing to sanitize the inner surface of mould organisms. Avoid loading the tubing with liquid.
Use a back-pack tank to carry isopropyl alcohol 70% dilution, and a dosing gun to apply 15 millilitres per spile.
Follow the label directions found on the container of isopropyl alcohol and obtain a copy of the guide produced by ACER in Quebec on proper application techniques for best results.
Only purchase isopropyl alcohol from maple equipment dealers who supply approved formulations. IPA is a controlled product, so it is important to respect the label instructions to ensure the maple industry can continue to use this sanitizer.
The same sponge technique used during cleaning can also be used with a sanitizer.
Step 3: Rinse
Tubing must be rinsed after sanitizing with potable water and/or with the first run of sap the following season. This will ensure there is no off-taste or residue in your syrup.
Ideally, spiles should be removed from maple trees before new leaves emerge and spring growth begins. The fastest healing of tap holes will occur during spring and early summer when the trees are adding a new layer of wood (the annual growth ring). If spiles remain in the tap hole during spring wood growth, the spile will prevent healing closure by new wood and bark.
To remove the spile, carefully give the spile a gentle twist before pulling it out of the tap hole. Twisting first before pulling will help prevent separating the bark and cambium layer from the underlying xylem, which could cause additional and unnecessary injury to the trees.
The above steps still apply, but you may choose to use an air compressor to push a sponge through between steps.
- Use an air compressor to push a sponge through to empty the sap tubing
- Push through another sponge with the air compressor to empty the tubing
Wash buckets thoroughly with hot water, by hand or using a machine. If you use a sanitizing agent, make sure you rinse out each bucket thoroughly.
Smaller Tubing Systems
For smaller tubing systems, you may choose to remove the tubing for more thorough washing.
- Number the system (both marking trees and tagging the tubing) for easy re-hanging next year
- Roll up laterals and tie into bundles of about 25 taps
- Fill a tank with cleaning solution
- Pump solution into the bundle OR mount the bundle on a rack that rotates it through solution
- Let bundle sit in the sun for 1-2 days
- Flush thoroughly with clean water
- Store in a clean area, under cover
Source: University of Maine Maple Syrup Quality Control Manual
Updated April 2, 2021