Black spots and Hydrogen Peroxide

[mspina14]

This was my first year using tubing. I ran 5/16 tubing to about 100 taps on level ground and used a small diaphragm pump to recreate vacuum.

In the last few weeks, I notice black spots on the inside of some stretches of tubing, mostly sections that are in the sun:

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After reading several threads here about different techniques to clean tubing, I decided to flush the system with a food grade Hydrogen Peroxide solution.

I bought food grade 35% Hydrogen Peroxide from an on-line seller:

16527

I filled my sap tank with about 100 gallons of water and added about 2 quarts of the Hydrogen Peroxide to the water. I then removed the last spout on each of my 3 lines and pumped the solution from the sap tank through the tubing until it ran out of the last spout onto the ground. I let it run for about 10 minutes. Then I capped the spout and kept the lines filled with the solution overnight.

In the morning, I flushed the rest of the solution through the lines but the black spots on the inside of the tubing did not go away:

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:o

I'm not happy. Could it be that the Hydrogen Peroxide was inert?

Is there a way one can tell if Hydrogen Peroxide has retained its potency?

Looks like I'll be trying the bleach next :cry:


Mark

[MapleMark753]

I've found with using Hydrogen peroxide that it can leave residue and or spots there even after an overnight soak. In tanks, this was solved with a hosing out with regular water with a nozzle on it ( I don't use it on tubing, but on tanks). More volume/pressure took the spots right off.
Others with direct tubing experience may have other solutions (ha ha pun intended).
good luck--be good to hear your 5/16 overall experience too...that may be in another thread, I've not looked yet.
:)

[Flat Lander Sugaring]

I would be very careful with bleach.
Those black spots i dont believe are just going to come out of tubing, you would have to rub or scrub and thats not going to happen.

How old is the tubing?

[mainebackswoodssyrup]

We suck hydrogen peroxide through our taps with the vacuum pump on when pulling taps. It helps flush out the drops but it does little for the lateral tubing lines. You're not going to get that mold out with any cleaner. Some of that will get sucked through next year during sap runs or you can cut it out and replace it.

[maple flats]

Cleaning tubing is best done within a few days of the end of the season, before any mold begins to show. When you pump the hydrogen peroxide solution up thru the tubing just let it discharge 3-4 minutes, then plug the tap into or onto the tee. Leave the mixture in all year. With the sunlight the mixture will soon break down into oxygen and water. Then prior to next season, mid-late fall, flush with good water and drain. The extended contact will kill most micro organisms and leave the lines clean.
This works, but most are now doing the dry clean method, run the pump until all sign of moisture is gone and leave the lines plugged at each tap. I used to use the food grade hydrogen peroxide method, but have since been using the dry method (for 6 years now). On that, the sooner you get it dry after the season the better too.

[Maplewalnut]

Chemically hydrogen peroxide breaks down into harmless water droplets. Thats why is lines are not flushed well or allowed to air dry you will develop mold where water droplets remain.

[mspina14]

Yeah, I realize now I should have flushed the tubing right after the end of the season.

Being new to using tubing, I didn't realize time was of the essence. Live and learn.

The bad news is the tubing has only been used one season. So I'd hate to have to replace it all.

The good news is that, so far, I only see the mold spots in about a 100 foot long section. If that is the only section I have to replace, its a quick fix.

Next year, I may try the dry air clean method and see how that goes.

Thanks for the advice.

Mark

[maple flats]

Yes, just replace that 100'. However, if more spots develop, they will also need to be changed. You may not get more are you may get lots more, only time will tell. Good luck.
Some wait until the next season and let the sap run a day to flush the lines and dump that sap on the ground. Then they only change any that doesn't come out. The problem with that is that you are dumping what could be the best sap of the season and if it turns out to be a short season you may be dumping a higher % than you really want to.

[mspina14]

Interesting.

So why would the first sap of a new season remove black mold spots on the inside of tubing?

Sap is mostly water. If the Hydrogen Peroxide solution didn't remove the mold spots, why would sap?

Just curious.

thanks

Mark

[MapleMark753]

Alright so before you bail on hydrogen peroxide, do you know what percentage hydrogen peroxide solution you put through your lines? Yeah, yeah, I can read the above, but you were writing in approximates I think. I do NOT mean to insult or anything like that, its just that well, it don't matter if you buy magic ju ju juice, if you dilute the juice too much it aint magic no more.
take care
mark

[Super Sapper]

If my math is correct you used approx. a 0.175% solution which is pretty weak.

[maple flats]

Back when I used the 35% Food Grade Hydrogen Peroxide, I mixed 1.5 qts in 100 gal of water, but I pumped a mixture of solution and air which gave good turbulence and cleaned well. To do that I made a manifold that connected to my mainline. It had a 1" inlet from my sap pump which pushed the solution and another inlet that connected to an oiless compressor to add air which I ran off a generator. The mix of solution and air made a big difference and gave good cleaning action.

[GeneralStark]

If the mold isn't plugging the line, why worry about it?

[johnallin]

This was my second year with 3/16 tube.
I have two types, one is light blue the other is darker.
The only black spots I see are in the dark blue lines.
Not sure why, but that's what happened over here.

[mainebackswoodssyrup]

The strength of the peroxide won't make any difference. The only thing that will is creating some agitation in the line like what maple flats did. I would think replacing some of the line would be more economical. Those are just small spots, keep an eye on them. I'll usually only cut out sections where there is a large spot, say 2" long that has started in the tubing. You might find that those small spots go away.

[lew]

From what research I've read, it really doesn't matter if you can see bacteria or mold in your lines. If it's not new, it's dirty.

[DrTimPerkins]

From what research I've read, it really doesn't matter if you can see bacteria or mold in your lines. If it's not new, it's dirty.

Put another way, at best, visual methods are a poor indicator of tubing sanitation and are not reliable for determining line cleanliness and the impact of microbes on sap yield. Best it does is perhaps make you feel better if the lines look clean.

[mspina14]

Hmm.

Interesting. So a tubing line that has visible black mold inside the tubing is not really any different than a line that has been flushed with some disinfecting solution and is clear?

Mark

[DrTimPerkins]

So a tubing line that has visible black mold inside the tubing is not really any different than a line that has been flushed with some disinfecting solution and is clear?

Not what I said. What I said was that you can not reliably tell whether tubing is "clean" (free of microbes) via visible inspection. Tubing may look clean and clear, but have a sizeable microbe load or look "dirty", but all the microbes are dead and therefore will not affect yield.

[mspina14]

Yes, that makes sense.

Does the microbe load in the tubing effect sap, either in quality or quantity?

I assume because sap is boiled so long in the syrup production process, that not many, if any, microbes survive by the time sap gets to be syrup in the evaporator. Is that correct?

I know from reading your research Dr. Perkins, that microbes in the spout and tap hole can have a serious impact on the quantity of sap.

But is quantity effected by microbes in the tubing?

thanks

Mark

[maple flats]

The microbes don't survive the boiling, but they do contribute to darker syrup to some extent.

[DrTimPerkins]

Does the microbe load in the tubing effect sap, either in quality or quantity?

Higher microbial load causes higher sucrose inversion, which results in darker and stronger tasting syrup.


I assume because sap is boiled so long in the syrup production process, that not many, if any, microbes survive by the time sap gets to be syrup in the evaporator.

The microbes are killed by boiling. There should be none left after boiling.


But is quantity effected by microbes in the tubing?

Yes, backflow of sap can occur from the sap collection system -- primarily from the spout, but also a good bit from the drop, very little from the lateral line, and none from the mainline. That is why changing droplines periodically (if you don't use CVs) will increase sap yields. Backflow seems to be able to come from further back in the line in 3/16" than 5/16" lines due to the smaller internal diameter.

[mspina14]

Thanks Dr. Perkins.

I'm a student of the industry. So I appreciate your response (and research work). I apologize if these questions have been already answered in this forum.

So if microbial load in the tubing causes higher sucrose inversion, which results in darker and stronger tasting syrup, is it correct to assume that some kind of tubing sanitation process would have a beneficial effect on syrup quality (assuming of course, that one prefers lighter, more delicate tasting syrup to darker, stronger tasting syrup).

The three tubing sanitation processes I've read about on MT are flushing with Hydrogen Peroxide, flushing with bleach (Sodium Hypochlorite), and "air drying" (pulling taps at the end of the season with the vacuum running).

Do each of these processes provide a sanitation effect on the tubing?

Is there any process that has been determined to completely eliminate all microbial loading in tubing?

Thanks

Mark

[DrTimPerkins]

So if microbial load in the tubing causes higher sucrose inversion, which results in darker and stronger tasting syrup, is it correct to assume that some kind of tubing sanitation process would have a beneficial effect on syrup quality (assuming of course, that one prefers lighter, more delicate tasting syrup to darker, stronger tasting syrup).

That is the assumption, however it has not been rigorously tested. Because regrowth happens so quickly, the effect is very transient. The flush of liquid down the lines during a good sap run probably has much the same effect. When sap flow slows to a trickle during a warm spell, regrowth in tubing systems is very fast. Studies have looked at in-season cleaning (in addition to pre-season cleaning) seem to indicate that the sanitizing effect is very short-lived.


Is there any process that has been determined to completely eliminate all microbial loading in tubing?

No such thing exists (at least nothing that is legally allowed or safe enough for producers to use). All "sanitizing" treatments will reduce microbial contamination during the time that the sanitizer is used, but in many cases, they will regrow fairly quickly. Part of sanitizing is removing material that the microbes feed upon so that regrowth will be reduced.

[mspina14]

Thanks Dr. Perkins.

Very enlightening.

I didn't realize the microbes grow back so quickly in the tubing. If the tubing is "sealed" at both ends, how do they get in there?

I guess some are always in the tubing, even after a thorough flushing with a sanitizing solution.

If the tubing is flushed with a sanitizing solution or "air dried" at the end of the season, is there less microbe growth in the tubing than that which occurs during the season (between sap runs, for example)?

Mark

[maple flats]

They are in there from the first day sap entered the tubing. The sap of a healthy tree is essentially sterile, but as soon as it leaves the tree that changes. Regardless of which if any method you use to clean or sanitize tubing, it is never totally effective, some microbes still reside in the tubing and it's pores, ready to grow again.