uv light seems to cloud sap???

[markct]

i have a 10 gpm uv light that i have setup inside the wall of the sugarhouse and has hoses that run out to my milk tank next to the sugarhouse and it recirculates with a 6 gpm submersible pump. i have noticed that a couple times i have had sap left overnight in the tank and left the light on recirculating the whole day and the next day it looked slightly cloudy, at first i just thought it was the sap degrading which seemed odd as cold as it is anyhow. but then i noticed that i had sap from the same day in another milk tank with no uv or anything that actualy is more in the sun, and that stayed crystal clear??? any ideas or experiences?

[Bucket Head]

How warm was the sap that had been recirculated all night? Does your tank have a working thermometer on it? I could'nt tell you how "hot" the light gets, but it must build some sort of temperature. Maybe your sap was getting slightly heated, repeatedly all night, and the bulk tank being insulated held the heat. Why recirculate it all night? Just run it through once and see what happens.

Steve

[markct]

yea i wondered that but there was still ice in the tank on the top most of the way so it couldnt have warmed it too much? i have heard of others setting up there lights this way so was surprised to notice this slight cloudiness

[Brent]

Are you using a drinking water UV sterilizer ????

There may be other reasons but the only one I can think of is that stuff is growing in the sap.

If you have a traditional drinking water UV it will have very limited success on sap. The sugars in sap reduce the transmission of the UV a huge amount. People who make commercial UV sterilizers for sap put in something like 4 or 5 bulbs that are very strong and very close together so the sap is close to the light source. This of course makes them much more expensive than drinking water sterilizers.

[markct]

yes it is a water uv light, thats why i am running it at a reduced flow rate to help with the lesser penetration as had been recomended by a few others. still tho i cant see why it would make it cloudy tho? seems like it has to be killing something? the sap that wasnt in the tank didnt cloud, im thinking maybe just let it run for a hour or two next time and then sit overnight

[markct]

yes it is a water uv light, thats why i am running it at a reduced flow rate to help with the lesser penetration as had been recomended by a few others. still tho i cant see why it would make it cloudy tho? seems like it has to be killing something? the sap that wasnt in the tank didnt cloud, im thinking maybe just let it run for a hour or two next time and then sit overnight

[Brent]

Could be that the agitation is mixing the sugars with the microbes better than in the stagnant tank. Is it warmer than the other tank ? More sunlight ?

The 'Sap Saver' commercial UV price I saw was something like $2500. If you've got a drinking water unit that cost a few hundred dollars, you'll get a huge difference in results, possibly could be worse off just by the circulation making it easier for the microbes to feed. Sap that has been concentrated will go bad in a fraction of the time that raw sap will just because the is more food in the concentrate.

Keep it going and see what happens.

OH ! Do you have a filter in the system ? A filter becomes an incubator for the microbes. They park in it and the food flows by.
You either have to change it frequently or run without it.
A filter in an RO gets pretty foul in 24 hours.