What happened to my sugar?

[Tweegs]

This morning I collected the following:

15 gallons from the silvers @ 1.6%
45 gallons from the buckets @ 2.6%
160 gallons from the main bush @ 2.3%
45 gallons from the secondary bush @ 2.5%

Six hours into the boil it became painfully obvious I wasn’t going to get the amount of syrup I expected from this run. I did not test the content once all of the collections were mixed in the holding tank, just figured I have something over 2% and set about boiling. With this amount of sap at roughly 2%, I expected something near 5 gallons. At the six hour point, or nearly 180 gallons processed, I had less than 3. I tested the sap in the feeder tank at 1.5%, which explained why I wasn’t getting syrup. I wound up with 3.25 gallons.

What happened??

Some background:

I finished off all the sap at the last boil, cleaned both the feed tank and the holding tank. It is almost impossible to completely drain the holding tank, but there was no more than a cup or two of clean water in it and I used only hot water to clean them.

The feed tank is set up high inside the shack, todays temps hit 60 and it was a literal sauna inside the shack, but the sap felt cool, even at the last, 45 to 50 as a guess.

The wood and metal above the feed tank were dry, no condensation dripping into it.

Double checked the cal on my refractometer, dead on 0 with distilled water.

I’m at a loss to explain this.
Any thoughts?

[500592]

Have you drawn off syrup before or did you drain the pan and boil it all cause that is were all your syrup probably is.

[Tweegs]

I don’t drain the pans after a boil, nor do I flood the pans at the end of a boil.
In fact, I take great care to make sure I keep the gradient established between boils. I can explain in greater detail later if you are interested.

The question again, stated perhaps a little more clearly, is:

I put 265 gallons of sap that that should have been over 2% into a freshly cleaned holding tank. This was transferred to a freshly cleaned feed tank for processing.

Why, over the course of the day, did the measurement in the feed tank drop to 1.5%?

(That's where all my syrup went :lol:)

[jmp]

Microbial degredation possibly? Yeasts and microbes that occur naturally can decimate the sugars quickly in the right environment. I may be way off base here but its just a thought.

[happy thoughts]

I was thinking the same as jmp. Also did you recalibrate after every reading? Maybe one or some of your readings were off?

[Tweegs]

I calibrated before taking the first reading, and since all readings were taken within an hour I didn’t bother to check it again until after I got the 1.5% measurement in the feed tank. It was also my thought that something was whacky with the refractometer when I took the original readings, but the cal after the feed tank measurement was dead on. Can’t rule it out totally, but the microbial degradation is more likely, I think.

It doesn’t seem to fit that I could lose over half a percent in sugar content, in the span of a few hours, just due to heat. There has to be another factor, or combination of factors, that could cause it to drop, or appear to drop, that rapidly.

The amount of syrup I pulled off supports the final 1.5% measurement. I’ve got something else going on, just can’t put my finger on it and I appreciate you folks steering me towards possible solutions. I guess the place to start is to thoroughly check my instrument and then start looking for a source of contamination.

[RollinsOrchards]

Well i haven't considered this before this moment, but does the sugar "rise" in tanks or buckets? Sort of like cream floats to the surface of the milk? With that refractometer you are taking a sample from the top inch or maybe two of the tank or bucket. Next time you gather take that sample off the top, and then agitate the container and sample again, the results may be interesting.

Something else might be: did you test every bucket, or just a one? If you tested one bucket tree at 2.6% but had a bunch at 1% that would change things.

[Michael Greer]

At the end of our season, we had a similar sense that something was happening to sugar content. I put my head into the tank to take a good whiff and sure enough, it smelled like someone was making bread. Yeasts are busy little critters, and can go through a batch of beer making ingredients in just a few days.

[Maplehobbyist]

Taken from the Wiki for Brix:


Alcohol has a higher refractive index at 1.361 than water at 1.333. As a consequence, a refractometer measurement made on a sugar solution once fermentation has begun will result in a reading substantially higher than the actual solids content. Thus, an operator must be certain that the sample he is testing has not begun to ferment, if the results are to be relied upon.

As yeast and bacteria occur naturally in maple sap, it's not out of the realm of possibilities that the sap had started to ferment, which might explain what happened to your sugar and why you got so little syrup. If it was a sauna inside your shack, it seems entirely possible that it was warm enough inside your feed tank to allow some yeast to munch on your sap.