Concentraterd Sap Spoiling

[OCHTO]

My sugarbush and cabin are 70 miles North of my home. Last year I collected sap about every 3 days, brought it home and cooked it to great tasting syrup with turkey cookers. Took days and days to cook it all and the expense of propane made me build an oil tank evaporator. Took that to the cabin. The first weekend of April this year I had enough sap to cook. Sat. Sun. and Mon. we cooked down about 60 to 70 gallons a day. At the end of the day I drained the 2 X 4 pan into 5 gallon jugs and buried them in a snow bank. Sat and Sun some of the concentrated sap was left in the evaporator and more fresh sap was added. When I got home all the jugs went in freezers until I had time to boil it down to syrup. When I did boil it down the jug from Sat. that had been in the snow the longest was the good syrup. The jugs from Sun. and Mon., as the sap boiled down it started smelling bad, like sour and it started leaving a sour bitter aftertaste. But it was sweet. Hard to describe but not good. Did my sap spoil in my evaporator and my jugs? So the next weekend I boiled 70 gallons of sap on Sunday. Clean evaporator, Fresher sap, and at the end of the day the concentrated sap was drained into jugs buried in the snow and taken home the next morning and boiled that afternoon. Bitter sour syrup again. Is the concentrated sap spoiling in my jugs in the snow? When I try to filter the syrup it coats the filter with a amber colored jelly. I didn't think there would be spoilage due to bacteria as all the sap is sterilized before going in the jugs. What's going wrong? My evaporator only does about 7 gallons an hour so can't make a full batch of syrup in just one day. I was afraid to leave the concentrate in the syrup pan overnight because of bacteria but Maybe I should have. Suffering bad depression due to lack of syrup for my waffles and pancakes. Need help! Already losing weight. Thanks

[happy thoughts]

Did my sap spoil in my evaporator and my jugs? So the next weekend I boiled 70 gallons of sap on Sunday. Clean evaporator, Fresher sap, and at the end of the day the concentrated sap was drained into jugs buried in the snow and taken home the next morning and boiled that afternoon. Bitter sour syrup again. Is the concentrated sap spoiling in my jugs in the snow?

How is the collected sap being stored and how old was the "fresher" sap? How clean was the collection tank and how warm were the temps in the days before you boiled? You may kill off microorganisms by boiling but that doesn't mean they haven't spoiled the sap and affected the taste before the sap hit the evaporator.

[mountain man maple]

What jugs are you using if plastic it could be holding heat and spoiling before it cools. I would think if you cool it before putting in containers that would help.

[happy thoughts]

In addition to what mountain man said, how clean were the storage jugs? Were they sanitized before filling? If they were not thoroughly clean you may have inoculated the concentrate with a heavy load of fresh microbes that were all too happy to find themselves in a sugar rich environment. Cold temps slow microbial growth but does not stop it completely.

[OCHTO]

I ruled out bad sap as the oldest sap I boiled made the best syrup. The batch I boiled down from fresher sap was collected the day before and the morning of the boil. It still made bad syrup. From your responses I'm hearing that it probably is a bacteria spoilage issue? The temps the weekend I boiled were in the upper 50s and around 30 at night. I'm just shocked that bacteria could grow that fast? My plastic jugs must hold heat more than I thought. Maybe the concentrate I drew off and put in the snow the first day was cooler and didn't spoil.

[Russell Lampron]

I ruled out bad sap as the oldest sap I boiled made the best syrup. The batch I boiled down from fresher sap was collected the day before and the morning of the boil. It still made bad syrup. From your responses I'm hearing that it probably is a bacteria spoilage issue? The temps the weekend I boiled were in the upper 50s and around 30 at night. I'm just shocked that bacteria could grow that fast? My plastic jugs must hold heat more than I thought. Maybe the concentrate I drew off and put in the snow the first day was cooler and didn't spoil.

Maybe the concentrate wasn't hot enough when it went into the jugs. If it is 180* or higher it will kill any bacteria in the jug preventing spoilage and more bacteria growth.

[happy thoughts]

I ruled out bad sap as the oldest sap I boiled made the best syrup. The batch I boiled down from fresher sap was collected the day before and the morning of the boil. It still made bad syrup. From your responses I'm hearing that it probably is a bacteria spoilage issue? The temps the weekend I boiled were in the upper 50s and around 30 at night. I'm just shocked that bacteria could grow that fast? My plastic jugs must hold heat more than I thought. Maybe the concentrate I drew off and put in the snow the first day was cooler and didn't spoil.

Sour taste and a jelly like consistency definitely says spoilage to me. I don't think you can rule out bad sap. Older sap treated well or at least kept very cold in clean containers could easily make better syrup than fresh sap that was kept at warmer temps in contaminated buckets.

Even pouring hot concentrate into a bucket will not insure it's sterilization if the container was heavily contaminated to begin with. That works OK when bottling correct density syrup into very clean containers in part because a very clean container has minimal microbial growth and also because correct density syrup is itself a preservative. But under-dense concentrate does not have the same ability to retard microbial growth and may instead encourage it.

Bottom line- as the temps get warmer, keeping sap and concentrate very cold and cleanliness of all equipment becomes even more important.

[OCHTO]

What can I do? I have a 2 x 4 batch pan. What does anyone do at the end of the day if they have a small evaporator?

[michiganphil]

What can I do? I have a 2 x 4 batch pan. What does anyone do at the end of the day if they have a small evaporator?

In your original post you said that you couldn't evaporate enough in a day to finish a batch, and you said that you were boiling Sat. & Sun. It shouldn't spoil overnight...leave it in the pan. You said that you didn't want to leave it for fear of spoilage, but I think you have a greater chance of introducing bacteria by cooling, pouring into buckets, letting the evap. sit empty, pouring back into evaporator. You would be handling it far less, and your boiling pan will be sterilized after a day of boiling on it.

[maple flats]

I agree, My pans are not drained from the start until the season is over, regardless of whether the reason for no sap flow is too warm or too cold. I just make sure the last sap to go into the evaporator has enough time to boil. I do this by setting the float about 1/4" higher than normal and when the sap flow reaches that higher level, I quit adding wood, then at the point when I'd normally add more wood (every 9 minutes) I close the feed valve. The pan is at full boil for at least 20-30 minutes and then the boil slows and eventually stops. I don't add more even as the level gets down to about 1/2" in the flue pan. I just shut down and after the fire is nearly all burned out, I cover the syrup pan and close up. I have had my pans set like this for up to about 8 days with warm temps and longer than that when too cold. Doing it this way, I never got bad tasting syrup unless it was very late in the season and I would have been making commercial syrup. At that point it could taste bad, but I never let it set at that time waiting for more to boil.
With all the handling you do, you are likely causing your problem. As you get towards the end of your day's boil, just add enough to boil and let it boil at least 15 minutes, then just shut off the burner, cover the pan and leave the contents in the pan. The pan is likely cleaner than what you are putting the "sap" into, and it will cool faster right in the pan, than in a full plastic jug in the snow.

[happy thoughts]

I still think the spoilage is happening long before the sap hits the evaporator. I'm assuming you are not collecting sap daily since your trees are so far away. Put a quart of milk in an unwashed container and let it sit outside for 4-5 days when day temps hit the 50's. You can boil that milk and kill all the bacteria but you still won't be able to make it taste good. Sap should be treated like milk.

[OCHTO]

Thinking about sap and bacteria. Sap bags must be full of bacteria. So when I empty the bags into 5 gallon jugs it must be primed for spoilage. This year was bad here for collecting promptly due to snow storms and commitments. When I do have to leave after a day of boiling I could put my concentrate in 16 qt. stainless pots and pack them in snow. It would cool a lot faster. The pots are only 12 $/pc at wal mart. If leaving it in the evaporator all I have to do is boil the last sap 20 to 30 minutes? What can I cover my pan with? Plywood gets condensation and drips and might add bad flavor. Sheet metal?

[Russell Lampron]

Thinking about sap and bacteria. Sap bags must be full of bacteria. So when I empty the bags into 5 gallon jugs it must be primed for spoilage. This year was bad here for collecting promptly due to snow storms and commitments. When I do have to leave after a day of boiling I could put my concentrate in 16 qt. stainless pots and pack them in snow. It would cool a lot faster. The pots are only 12 $/pc at wal mart. If leaving it in the evaporator all I have to do is boil the last sap 20 to 30 minutes? What can I cover my pan with? Plywood gets condensation and drips and might add bad flavor. Sheet metal?

If it's under cover don't cover it with anything. If your set up is outdoors maybe a piece of foil backed foam insulation with something to hold it down.

[happy thoughts]

What exactly is your collection routine? Are you only able to visit your site on weekends? If so, maybe you need to rethink the process, especially toward the end of the season when the weather turns warm. Or just call it quits earlier than you might want to.

Can you expect good snow cover most years? If so, spouts on tubing to 5 gal food grade buckets buried in the snow will keep your sap colder than sap bags hanging all week on a tree. Food grade buckets are often free from bakeries and donut shops. If you get extra, you can switch dirty ones for clean ones after each collection. A 10-15 minute boil should be enough to kill*most microbes but it's not going to stay in that condition all week. it will help but it won't prevent new spoilage. Between boils you may be better off keeping things as cold as possible. You can try freezing some sap or water in plastic bottles and float them in the buckets. Again that will help for a few days but not enough to last a week.

How much concentrate are you talking each week? JMHO, overnight, no problem, but even if you can cover your evaporator well, to expect it to last until the next weekend's boil is pushing it when daytime temps are in the 50's. Could you bring it back home for finishing on your turkey fryer? Or freeze it at home until the next boil. You can try burying it in snow for a week but again I think you're pushing it.

[OCHTO]

I collected sap this year once after 4 days but usually every 3 days and then the temps were low after snow storms. I boiled on weekends, once for 3 days in a row. I wouldn't keep my evaporator with partly cooked sap for a week, I would take the concentrated sap at the end of the day home and put it in the freezer. I like the idea of having frozen sap to add to the concentrate to cool it down and rotating clean jugs. My evaporator is outside. If I covered it with foil faced foam wouldn't it keep the heat in longer and increasing bacteria growth. What would be wrong with a piece of sheet metal?