Suggestion on cleaning take down tubing

[john henry]

I take the majority of my tubing down each year at the seasons end. Back at the sugar house I have been flushing it 1 line at a time with air water mixture making sure each drop gets a good flush. I then blow air through each line to get out most of the water. I have 5/16" tubing and also some 3/16" with 5/16" drops. If I were to make up a tank of bleach / water solution and pump this into the lines 1 at a time making sure each drop is filled how long should I let the solution in the tubing? Then how long/much do I flush this out with fresh water to be sure I got it out? I assume if I flush it all out real good that I won't have to let any sap run on the ground the next season, correct? Also do you have a recommendation on how much unscented household bleach to use with the fresh water? Such as how much bleach per 100 gallons of water. Other washing suggestions would also be appreciated, thanks for your time!

[DrTimPerkins]

1:20 standard bleach (5.25% sodium hypochlorite) to water solution is recommended with a minimum contact time of 5-10 minute. Follow this with a copious rinse of fresh water. As long as you rinse well, you won't need to let sap run on the ground. Note that some bleach formulations contain substances other than just sodium hypochlorite. These are best avoided. Will work with 5/16" or 3/16" tubing systems. Might attract squirrels unless you rinse well.

[john henry]

Thanks for your help Dr. Tim on this. I do have squirrel issues in some areas. So hopefully If I rinse well inside and out I won't increase my typical damage.

[DRoseum]

Interested to hear thoughts on using food grade hydrogen peroxide which will break down to water over time yet has been shown to be very effective disinfectant against a wide range of microorganisms. Positives seem to be less concern for residue left behind and better for environment (returns to water).

1:20 standard bleach (5.25% sodium hypochlorite) to water solution is recommended with a minimum contact time of 5-10 minute. Follow this with a copious rinse of fresh water. As long as you rinse well, you won't need to let sap run on the ground. Note that some bleach formulations contain substances other than just sodium hypochlorite. These are best avoided. Will work with 5/16" or 3/16" tubing systems. Might attract squirrels unless you rinse well.

[jrgagne99]

1:20 standard bleach (5.25% sodium hypochlorite) to water solution is recommended with a minimum contact time of 5-10 minute. Follow this with a copious rinse of fresh water.

How are folks generally achieving the 5-10 minute contact time and subsequent rinse? I have a 150-tap mainline on vacuum and generally just pull my taps with the vacuum on (i.e. "dry" clean). Carrying around a gallon of bleach/water solution and sucking a bit up through each tap after pulling it would only result in a few seconds of contact at best... Furthermore, rinsing by back-flushing from the bottom of the line doesn't work because the water only makes it up about a quarter of the way, unless you plug taps as you work your way up the mainline.

Does anybody have a good procedure for a small operation such as mine?

[DrTimPerkins]

Does anybody have a good procedure for a small operation such as mine?

Short contact time (as happens by pulling a solution in under vacuum) is fairly ineffective. Hardly worth (or not work economically) doing.

You can either pump in a solution from the bottom, or if this is not possible, use an squirt bottle or injector to push in 15-20 ml of solution into each spout and drop, then cap it off or plug it and let it hang. Later go back and rinse, or allow the first sap run on the ground.

Interested to hear thoughts on using food grade hydrogen peroxide

Hydrogen peroxide is reasonably effective in terms of sanitation, but the cost effectiveness is on the low end of choices (due to the cost of the material and the labor involved). Short contact time with hydrogen peroxide produces negative net economic outcomes (meaning the cost of doing it exceeds the return you get in sap yield).

UVM and Cornell have a summary paper just out in the Oct 2019 Maple Digest describing 10 yrs of research on spout and tubing sanitation.

[Sugar Bear]

5-10 minutes is sort of a loose term and it implies the longer the better.

But for those of that can keep the mixture in our lines until the hot place freezes over, how long is the point of no more benefit to the sanitation effects of this procedure?

[SeanD]

The most recent Maple Digest has a comparative study of all the sanitation strategies people are using - including replacing taps, drops, etc. The sodium hypochlorite and the calcium hypochlorite did very well even against replacing the drop. I'm testing it out in a few ways in my own set ups.

I put about 100 all new taps and tubing in a new spot last year and it ran really well. At the end of the season, I cut off the drops at the tee and gave them a 30-minute soak (taps and all) in a calcium hypochlorite solution. I let them air dry. I considered rinsing them, but when I cut the drops off, I gave the laterals a squirt of sanitizer for good measure. I'll have to let the first run go to the ground anyway. Next year, I'll reinstall those drops with new tees but reuse the taps.

My other woods have drops in various ages of 1-3 years. For those, I left the drops on, but used a squirt bottle to fill the drop with sanitizer and plugged it. I didn't time it, but by the time I walked the lines to fill and plug them then go back and pull them to drain them, it was way beyond ten minutes. I think I left many overnight. I take all my lines down like you, but you could actually leave the solution in there indefinitely. Eventually, it will break down.

If this all turns out to work as expected, it could be a game changer. Walking through the woods with a couple of squirt bottles is the easiest method yet for me - even when the lines run overhead.

[DrTimPerkins]

5-10 minutes is sort of a loose term and it implies the longer the better. ...how long is the point of no more benefit to the sanitation effects of this procedure?

In terms of sanitation, longer than 5-10 minutes is not better (or worse). Shorter than that and the sanitation efficacy drops off (you won't have achieved the full effect). Longer than that doesn't help (there is nothing left to kill).

Same goes for concentration. Stronger than recommended is not going to help. Weaker than recommended won't achieve the best kill rates.

The approach that is often used, but is NOT very effective, is to suck the sanitizing solution in under vacuum. The contact time is just too short (less than a second or two).

[DrTimPerkins]

Unfortunately it isn't possible to attach PDFs, but here is the primary figure from the Maple Digest article (Dave and) I were referring to. It summarizes 10 yrs of research at UVM and Cornell on spout/tubing sanitation studies (replacement, cleaning, combination).

Perkins, T.D., A.K. van den Berg, and S.L. Childs. 2019. A Decade of Spout and Tubing Sanitation Research Summarized. Maple Syrup Digest 58(3): 8-15. Folks should try to find it and read it before asking a bunch of questions since they are likely to be answered in the paper. We publish the majority of our research there. Back issues are archived online. A subscription is $10.00/yr. http://northamericanmaple.org/index....-syrup-digest/

Maple Digest - Sanitation Summary.jpg