sap storage

[kboyer]

How long can sap stay in storage before it gets boiled? I saw someone talking about only boiling on the weekend and they may have 600-700 gallons from the weeks collection. Does it have to be frozen or can it last that long?

[Sugarmaker]

Kboyer,
I have never held sap more than a day, so not sure, but I would expect that you should keep it as cold as you can during storage. But I would not freeze it. Also you may loose some grade due to bacteria growth.
If you can try to boil what every you gather the same day, you will have the best grade and keep ahead of the sap flow. I know this is not always possible.

Regards,
Chris

[Tweegs]

Still working 40+ hours per week, my system involves taking vacation days every Wednesday through the season. I’m usually boiling before sunrise on Wed, when the wife gets home from work I put her on the evap while I go out and collect the days run, then boil until done. Makes for a long day if the sap Gods have been kind, but never have sap sitting for more than 2 or 3 days.

I don’t mind the sap freezing. Water freezes, sugar doesn’t. Remove the ice and it’s akin to a cheap RO, at least I think so, experimented with that some last year. One tree ran 1.9~2.1 typically. Removed the ice once and it measured 3.5. (that was from one 5 gal bucket). <shrug> may be more to it than that, but allowing it to freeze then removing the ice did seem to concentrate the sugar.

[DrTimPerkins]

....allowing it to freeze then removing the ice did seem to concentrate the sugar.

This works to some degree, however some sugar is trapped in the ice and will be lost when the ice is tossed out. Not a huge amount, but there is some. So it is more akin to an RO that has some sugar passage.

[Tweegs]

Interesting Dr. Tim.
I guess it then comes down to whether it is worth the additional expense in time and fuel to extract the sugar, and I’m sure an argument can be made on both sides.

I am curios now as to how much sugar I’ve been throwing away. I’ll experiment further next season and see if I can answer that. (My wife bought me a refractometer last year…kids, toys, you know how it goes :lol: )

Also, and getting back more to the OP’s topic, I suppose leaving some ice in the holding tank could help keep the sap cooler and retard bacterial growth? A tradeoff between more time/fuel vs. a potentially lighter grade?

[DrTimPerkins]

Interesting Dr. Tim.
I guess it then comes down to whether it is worth the additional expense in time and fuel to extract the sugar, and I’m sure an argument can be made on both sides.

There was a rather detailed study done by the Philadelphia Maple Lab many years ago (before the time of ROs). Citation is: Stinson, E.E. and C.O. Willits. 1963. Freezing Sap. Maple Syrup Digest 2(2).

They found that a lot of sugar was trapped in the ice. The more ice in the bucket, the more sugar was lost (up to 62% could be lost in a bucket that was 95% ice...about 5-10% loss with 10-30% ice in the bucket). This is a lot more sugar lost than would be in the passage of even the worst RO membrane.

Their summary section follows:

1. Do not discard ice from partially frozen or melted sap. The value of sugar lost with the ice exceeds the gain from lower oil consumption.
2. Dipping frozen sap in plain water or fresh sap has no advantage.
3. Discarding centriged ice which has been crused or rinsed has advantages. However this procedure would not be practical due to the high cost of centrifuging.
4. Discarding the ice from partially frzen sap appears economical only under unusual conditions wherein an evaporator could not proces all the sap supply or a maple farmer could not haul all of his sap run. Under these rarely encountered circumstances would it be advantageous to process only the liquid portion of the mixture since syrup solids are greater in the liquid phase.

Of course, oil prices were a lot cheaper then....but then again, evaporators were a LOT less efficient in those days as well.

Bottom line....don't discard the ice. Along those lines, leaving ice in the storage tank WILL ensure the sugar is captured, and will help to keep the sap colder. Don't taken it out.

[Littlesap]

So here's a question for those of you that boil every few days... what do you do with the sweet sap that remains in the pan during your shut down process? The guys that boil every day I suspect just leave it there for the next session but how long can you leave sweet sap in, say a 2x6?

[red maples]

I clean out my syrup pan after every use. when the boil starts to slow I will plug the pipe that goes to the flue pan. then let things cool a bit but I never leave beacase you don't want your "almost" syrup to get too low. and if need be I might add a bit of raw sap. anyway, I let it cool just a bit drain out the syrup pan and fill it with vinegar solution and leave it for the next day over the heat!! clean it out real good put it back on and then refill let things get good and boiling and then pull the plug then I don't get alot of back flow.

back to leaving it in the pan. if there is sugar there is bacteria, its one of their favorite things (too much then it becomes some what of a perservative) you need to bring at to boil every other day at least that my rule. or maybe you could wait 2 days. it does happen from time to time. If not you get a pan of snotty jelatinous bunch of nasty!!!! threre is a term for it but I don't remember it. I will drain my flue pan periodically to get all the niter and brown junk out of the pan I just run the concentrated sap through prefilters. clean everythign and dump it back.

hope that helps

[ejmaple]

red maples, when you drain your syrup pan while the rig is still hot don't you risk scorching the pan? it seems risky due to the film layer of near syrup on the pan.

[danno]

I think many of us leave our sap and syrup pans full between boils, and only empty it if we are cleaning or switching a pan. Generally, the only time I'm going more than 2 or 3 days between boils is when we have a cold snap and the sap is not running.

I'll empty and clean my syrup pan maybe once a week during the season. So, I guess that answers your question - if you are only boiling once a week, I guess I would empty it out and keep the sap cold.

[markct]

i know the times my sap has had to sit in the pans more than a few days its been because it was too cold to flow sap, so it was cold enough it kept just fine. also sap in the evaporator keeps better than sap in the tank because it has been boiled a bit and thus sterilized. i only drain the front pan to clean it, and the flue pan usualy only gets drained at the end of the season

[mike z]

From a "backyarders" perspective, (small batch operation) I have found that in the beginning of the season I can get away with holdong sap maybe a week before it starts to whiten. I do usually boil as it comes in. However, even if I've kept the sap ice cold at the end of the season, it starts to color after only one day.

[DrTimPerkins]

Partially boiled sap left in lead-soldered evaporators (especially lead-soldered backpans) will pick up a very heavy lead load in between boilings, even if it is cold. One way to reduce this is to drain the pans (into lead-free containers) between boils if you can.

If you have lead-free soldered evaporators (pre-1994 typically, pre-1991 for some Leader equipment), or welded pans, this is not a problem in most cases. However if you have a lot of sap collection equipment containing lead (lead-soldered buckets, spouts, galvanized tanks), or you buy sap from people who use lead-containing sap collection/storage equipment, the sugar sand/niter in the pans can contain a significant amount of lead, and it will be mobilized by the sap sitting in the pans between boils. In that case, it is still a good idea to drain pans.

Towards the end of the season or during a prolonged warm spell, sap/sweet left in pans and not boiled occasionally may result in "ropey" syrup.

[red maples]

red maples, when you drain your syrup pan while the rig is still hot don't you risk scorching the pan? it seems risky due to the film layer of near syrup on the pan.

there might be a slight risk but not really. At the piont at which I empty the pan there is no fire left in the firebox. its just residual heat from the arch itself which is hot and only will carmelize the pan if left un attended. this heat will last for hours after so you also wanna make sure you leave enough sap so that your pans don't dry out. The pan is not left alone for more that a second or 2. as soon as the syrup is out in goes the vinegar solution. not even a hiss from the pan!!!! There is more of a risk from letting the niter line the pan and create hot spots which can start to scortch the pan/syrup. The heated vinegar solution will help to release the niter deposits from the pan.

[WESTVIRGINIAMAPLER]

I sometimes hold it as long as a week. I have a 625 gallon sunset milk tank and I will freeze a few sap buckets full of sap and throw them into the tank of sap and just a few minutes the chunk of sap/ice comes out and fill them back up and into the freezer to throw in next day. I have had sap for upwards of a week and still made light syrup out of it, but only in the early season could you make light syrup from holding sap that long. Treat it like milk and it will keep longer. I live about 30 minutes from sugarhouse and work full time, have 2 small children, so you do the best you can.

[Slatebelt*Pa*Tapper]

Brandon do you use a UV light yet on your sap?? i did the frozen sap thing to and it always seem to make the sap last longer to..

[heus]

I clean out my syrup pan after every use. when the boil starts to slow I will plug the pipe that goes to the flue pan. then let things cool a bit but I never leave beacase you don't want your "almost" syrup to get too low. and if need be I might add a bit of raw sap. anyway, I let it cool just a bit drain out the syrup pan and fill it with vinegar solution and leave it for the next day over the heat!! clean it out real good put it back on and then refill let things get good and boiling and then pull the plug then I don't get alot of back flow.

back to leaving it in the pan. if there is sugar there is bacteria, its one of their favorite things (too much then it becomes some what of a perservative) you need to bring at to boil every other day at least that my rule. or maybe you could wait 2 days. it does happen from time to time. If not you get a pan of snotty jelatinous bunch of nasty!!!! threre is a term for it but I don't remember it. I will drain my flue pan periodically to get all the niter and brown junk out of the pan I just run the concentrated sap through prefilters. clean everythign and dump it back.

hope that helps
Red,
Do you actually remove the pan when you rinse the vinegar out the next morning or rinse it in place?

[WESTVIRGINIAMAPLER]

Brandon do you use a UV light yet on your sap?? i did the frozen sap thing to and it always seem to make the sap last longer to..

Charlie,

I do have a whole house stainless uv light that I run the sap thru before it goes into the tank. Don't know how much it helps, but can't hurt it any.