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Thread: Safe temperatures to store Sap vs Concentrate vs Syrup???

  1. #11
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    I used to just drain my pre-heater when I shut down, cover all openings (float boxes and pans). Then one time I had to shut down during a boil to clean the syrup pan. I didn't drain the pre-heater in the hood. I ended up getting my first (and hopefully my last) ever ropy syrup. Now when I shut down, in addition to always draining the pre-heater I also drain my cold sap float box, then allow the hot from in the flues pan to fill the float box. Problem fixed!
    Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
    Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
    Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
    After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.

  2. #12
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    Oneida NY
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    Sap is safe for 2-3 days if under 40F, longer if colder. Concentrate is safe if kept just above it's freezing point at whatever sugar concentration it is at. Syrup, awaiting bottling is ok at 40F for 2-3 weeks, maybe longer if a little colder.
    A walk in cooler can help but most of any size who set up to hold concentrate for any length of time use an operating dairy tank and cool it according to the sugar %.
    Whether your concentrate comes from an RO or from boiling or both does make a little difference. Once boiled the concentrate has had any micro organisms killed or mostly killed, thus that concentrate in the pans can be good longer than what was made solely by an RO. RO'd sap spoils fastest if not refrigerated according to it's freezing point. Recently the Maple News had a chart, (by Dr Perkins and others) showing sugar % vs freezing point. If cooled to 1-3 degrees F above freezing it lasts quite long without degrading.
    Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
    Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
    Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
    After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.

  3. #13
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    UVM Proctor Maple Research Center, Underhill Ctr, VT
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    Treat maple sap as it it were milk. Would you be comfortable drinking it after it sat out for a few days? Maybe...if the temperatures were really cold. Probably not if the temperatures were warmer. There is a strong influence of time and temperature on sap quality. Note that running sap through an RO warms up the sap...and it can warm considerably. We've measured concentrate temperatures up to 72 deg F coming straight out of the machine (we were squeezing it pretty hard). If you recirculate or do a double-pass through the RO it'll warm each time it goes through. How do you know when it is bad...hard to tell...kind of like when milk first starts to go sour. When it is warmer in the season and sap flows in the tubing system are low and slow, sap can heavily ferment in the lines before it even reaches the tanks. That stuff needs to be boiled right away, and even then will sometimes result in sour syrup (tastes bad and "fizzy" on the tongue). All depends upon time and temperature.
    Dr. Tim Perkins
    UVM Proctor Maple Research Ctr
    http://www.uvm.edu/~pmrc
    https://mapleresearch.org
    Timothy.Perkins@uvm.edu

  4. #14
    vtbackyardmaple Guest

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    Last year I buried my sap bin with snow. Only the lid was exposed and accessable. Snow lasted about 2 weeks and kept the sap nice and cold. Not a great solution but it worked.

  5. #15
    Join Date
    Jul 2021
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    Quote Originally Posted by DrTimPerkins View Post
    Spoilage is related to (other than microbe type and number initially present) three things: time, temperature and sugar concentration. They are interrelated to a fairly substantial degree.

    In general, the longer time (at temperatures above freezing and below boiling), the more growth of microbes. The higher the temperature (above freezing but below boiling), the faster the growth of microbes. The higher the sugar concentration (below 66 Brix), the faster the growth of microbes. The growth of microbes often follows an exponential curve (not linear), so although it starts out slow, growth gets faster and faster as time goes on (if resources...like sugar...are unlimited), kind of like a runaway train going downhill.

    Each type of microbe have a certain "window" they like to grow in for temperature and sugar content. Most grow well above refrigerator temperatures (45 deg F) up to below 120 deg F. Many microbes do well in sap, but will grow faster (divide into more microbes) in higher sugar concentration solutions such as concentrate (more food around to feed upon), but most can't grow in syrup (the water "activity" or availability of water) is too low. A few types specific types CAN grow in syrup, but these typically grow very slowly and are either not present or reduced in number if syrup is hot-packed.

    So the bottom line for sap is keep it cold and process it quickly. For concentrate...keep it really cold and process it ASAP. Keep in mind that running sap through an RO will warm it up (sometimes a LOT), and recirculating through an RO even more so, with the result that you've now made nice conditions for microbes to grow...a warm, concentrated sugar solution...a perfect place for microbes to make more microbes very quickly.

    Depending upon the style and configuration of the evaporator/float box, at the end of a boil some producers will pull hot sap/syrup off the evaporator and dump it into the float box to kill any microbes hanging out there (it's a nice warm -- but not boiling spot -- with a lot of sugar...kind of like a spa for microbes). The alternative is to shut off or plug the opening and drain the floatbox. Some floatboxes are tight to the evaporator and get really hot, so are less susceptible to this problem, whereas others have the floatbox kind of hanging out in space so they don't get hot enough to kill microbes. In this type of evaporator, the floatbox is the ideal spot for microbial growth, the most common of which causes ropey sap/syrup...a very nasty thing.

    Similarly, what happens to the sweet in the pan...if you don't boil regularly, it can start to spoil. You can either: boil regularly, draw off and refrigerate it, or fire up for a short time (boil for 5 min) every 2-3 days during warm slack periods to kill anything that starts to grow.

    Can we tell you exactly how long and at what concentration you can safely hold sap at. Not really. It all depends upon those things...microbe type and quantity at the start (keep your equipment clean), time (keep it short), and temperature (keep it cold). And if you happen to have that type of evaporator/floatbox...either "sterilize" it at the end of the boil, or drain it. That'll go a long way towards preventing the problem...but those nasty bugs may still occasionally find a way to bite you.
    Just reading this older post and it really made me rethink a few things.

    For my fifth steam pan, my preheat pan, if it does not come to a boil (which I am hoping that it will), that I should make sure that it is empty at the end of a boil and I should clean the pan.

    I still have to make my RO, but I can see from a microbial point of view, it makes sense to run it while you are boiling (perhaps start it while you are collecting sap, just before you start to boil) and have it positioned right by the evaporator and use the concentrate close to the time you produce it. I may have to add some raw sap time to time, to keep up with the boil.
    2022 - 5 pan block arch - 109 taps, 73 on 3/16 lines, 36 on drops into 5 gallon pails.
    930 gallons boiled, 109 L (28.8 gals) of delicious syrup made.
    DYI Vacuum Filter
    2023 - 170 taps, mostly on lines, 1153 gallons boiled, 130 L (34.34 gals) of delicious syrup made, on a 2x4 divided pan and base stack, 8” pipe, on a block arch that boiled at a rate of 13 gallons per hour.

  6. #16
    Join Date
    Jul 2021
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    Parry Sound Area, Ontario
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    Getting away from storing the concentrate, as I will be using it almost right away, but i have a question about the storage of syrup.

    If I bottle it correctly with heated bottles and syrup at 180 to 190°, and have them on their sides to seal the lids and kill any mold or bacteria, can I just store the syrup at room temperature in a pantry for a year or more, or does it have to be stored more in root cellar or fridge or freezer?

    Now that I have moved up to 110 taps, I likely am going to have some syrup hang around for a few months.

    Thanks

    Gary
    2022 - 5 pan block arch - 109 taps, 73 on 3/16 lines, 36 on drops into 5 gallon pails.
    930 gallons boiled, 109 L (28.8 gals) of delicious syrup made.
    DYI Vacuum Filter
    2023 - 170 taps, mostly on lines, 1153 gallons boiled, 130 L (34.34 gals) of delicious syrup made, on a 2x4 divided pan and base stack, 8” pipe, on a block arch that boiled at a rate of 13 gallons per hour.

  7. #17
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    Sep 2020
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    Corbeil, ON
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    If you hit the brix correctly and bottle to the temps you note, the syrup should be fine at room temperature.
    2021 - Year one. 15 taps using 5/16" and drop tube into buckets. Homemade barrel evaporator with 2 steam trays. 4.7L syrup.
    2022. 32 taps. Added AUF.
    2023. 51 taps. Ditched the steam pans for an 18x22 flat pan.
    2024. 56 taps. Built a proper evaporator to fit the 18x22 flat pan and 1 steam pan.

  8. #18
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    Apr 2013
    Location
    Speyside, Ontario
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    270

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    Yep, until opened and then should be refrigerated, although I know people that don't bother. Depends on how long it takes to go through a bottle I guess.
    2015 - 8 buckets, 332L sap, 8.5L syrup - Barrel evaporator, 2 steam pans
    2016 - 8 buckets, 432L sap
    2017 - 10 bags, 470L sap, 9L syrup
    2018 - 20 bags, 1050L sap, 17.6L syrup
    2019 - 20 bags, 970L sap, 22.2L syrup
    2020 - 17 bags, 813L sap, 17L syrup

  9. #19
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    Jan 2013
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    Tolland, Ct
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    Quote Originally Posted by Swingpure View Post
    Getting away from storing the concentrate, as I will be using it almost right away, but i have a question about the storage of syrup.

    If I bottle it correctly with heated bottles and syrup at 180 to 190°, and have them on their sides to seal the lids and kill any mold or bacteria, can I just store the syrup at room temperature in a pantry for a year or more, or does it have to be stored more in root cellar or fridge or freezer?

    Now that I have moved up to 110 taps, I likely am going to have some syrup hang around for a few months.

    Thanks

    Gary
    I just last month opened a bottle that was in my cabinet in the kitchen at home, since I made it last year (pleasant surprise since I thought I was out), and it tasted great!
    2020 - 1st year - 14 taps 1 Gallon Jugs + 4x 5-Gallon Buckets + Propane Grill + lots of headaches
    2021 - 2nd year - 19 Taps (and some free sap from a friend in the same town!) 145 or so OZ
    2022 - 3rd year - 46 taps (3 at home, 2 at neighbors, 38 at friends, and 3 at work) added ROBucket RB10, and Silver Creek 18x34x6 Divided Maple Syrup Pan w/warming Pan+Valve+Thermometer 6 Gallons 6 OZ!
    2023 And we grow some more... Starting with OldPostMaple.com!

  10. #20
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    Apr 2014
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    Wakefield,New Hampshire
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    As long as it is bottled like you said and at the right brix it will last for more than a year in glass at room temp. I actually have a bottle from my first season in 2015 still sealed and hasn't formed mold yet.
    Just remember sunlight will darken the grade, if that matters to you. I prefer my syrup to be very dark some people don't.
    6th season solo sugar maker in a young sugar bush of mostly red maples
    320 taps
    2x6 self built arch, Flat pans w/ dividers
    New 12x16 sugar house
    CDL hobby 250 RO

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