UV Light

[jamiesonmaple]

Since I can only boil on the weekends i was thinking of a uv light inside my tank to limit bacteria. Since uv light barely penetrates the sap I was thinking of putting the uv light inside a glass tube in the sap and leaving it on until the weekend. Also, to make sure the light gets to all the sap ill put in a small circulation pump. Could this work?

[sugarsand]

Not sure how effective this system is, but I think there was various post in the past either here or on SBI. Try checking the archives, good luck.

Sugarsand

[5050racing]

Pack it in the snow,cover it and good to go,I go 4,5 days this way for years.if you need snow come over i will give you some!!!

[markct]

Look into a water treatment uv light to circulate it thru. I use a 10gpm one to treat the concentrate coming out of my ro and it keeps it way clearer and less slime in the tank for sure

[OldManMaple]

A small pump may be ok but running a pump constantly may heat your sap up.

[Snowy Pass Maple]

One way to approach this might be to have a holding tank that only sees sap after passing through the UV - and pass that sap through the UV well below the rated flowrate. This will help somewhat make up for the fact that the sap will have higher UV absorbance than pure water, and thus a higher "dose" is needed to be effective at penetrating the sap as compared to pure water.

Much of what I've read suggests that once a tank has any microbial contamination, a small UV can't possibly keep up with it as you have so much going on in that tank already. And I think it's safe to assume that anything you bring in from the woods will be loaded up with microbes, thus I think taking care to knock that down as much as possible before it ever enters a final super-clean holding tank would probably be much more effective.

The catch with this approach is that you will probably need a second tank - and you'd probably still want to do some frequent cleaning of the long-term holding tank.

If we recirculate for RO, we often use a similar approach - on our first feed into the RO, we go through UV while the sap is at a lower sugar, and the UV is more effective - and then the concentrate goes into a clean tank. Then if we recirculate, we are bringing in sap that is hopefully much lower microbe count vs. circulating back into the main holding tank. We still pass it through UV again, but I suspect the value of this decreases quickly as sugar goes up.

I don't have the data to prove how effective or not it is beyond noting that we have made a LOT of light syrup like this - even when running RO only to 6% sugar and a simple flat 3-divider pan. And we struggle to make Grade B - thus I think the somewhat anal-retentive cleaning and prevention steps are doing something. This year, at some point, I may just turn off the UV and cut our cleaning frequency just to get some darker syrup out.

I would think there must be published somewhere absorption/transmission curves for maple sap as a function of sugar level, and microbial kill rates as a function of UV dose - that information should help one make a more intelligently designed setup running a tap water UV at a much slower throughput.

[markct]

Yes i forgot to mention slower flow is better. My 10gpm water uv light gets less than 2gpm of concentrate thru it off my ro and works very well