An interesting article popped up in my reading about isopropyl alcohol used in cleaning maple sap tubing. Apparently it is being used in Canada as a cleaning agent in flushing out maple sap tubing when the season is finished. It has been somewhat effective in the cleaning process but here is the rub. This chemical is banned by the EPA in the United States for such uses. Isopropyl alcohol is considered a pesticide by the EPA and is banned from use in the USA as it has not been reviewed to show that it is effective and safe for this use.
On our farm we have only used water and compressed air to clean tubing for some time now. We were not aware that Canadian operations could and did use other compounds in cleaning. Apparently the tubing must be well rinsed to eliminate the alcohol from the system before sap from the system can be used to collect sap for boiling down into syrup. There doesn’t appear to be any standard procedure created to ensure that the system has been adequately rinsed. Producers are “on their own” to decide if the system is alcohol free or if they even need to rinse.
Not all Canadian producers are using isopropyl alcohol and many of those that are using it are probably rinsing their tubing after using it but no one has done any research as to whether residues are showing up in Canadian maple sap or maple syrup. One thing is clear. It is illegal to use isopropyl alcohol in maple tubing in the United States so US syrup should not have any residues in it.
Fresh maple sap collected.