1st timer: backyard syrup has off smell and taste

[reganzzzz]

We tapped our one tree this year as a homeschooling project. 1 new plastic tap, 1 new plastic tube, going into empty gallon spring water containers. The sap looks clear as water and has no odor. We evaporated it indoors on the stove because it's only a gallon at a time. No odor until we get down to the stage where it boils and thickens and turns golden... then a smell emerges that is best described as musty.

I brought the bad smelling syrup to the local nature center's sugar house and they were all stumped.

Every separate gallon has ended up the same way, no matter what day it was collected. We tried boiling it in different pots. All pots were first scrubbed clean with soap, then a vinegar soak, then a boil of plain water. The only consistent thing is the tree and the tap/tube.

What could the cause be?

Here's a photo of the tree in November, for those who wonder if it's not a maple: http://experimentsinformandfunction.tumblr.com/image/79907567395
and another, better view of leaves: http://experimentsinformandfunction.tumblr.com/image/79963530125

We are in CT and the tree is not yet budding. Should I try tapping the other side of the tree in case the tap is in bad wood?

[old tom]

Are you sure you tapped a Maple tree?

[COMSTOCK MAPLES]

I'm thinking the same thing. some trees look sorta like a maples. That's my best guess Good luck !!

[reganzzzz]

Here's a photo of the tree from November:

http://experimentsinformandfunction.tumblr.com/image/79907567395

[COMSTOCK MAPLES]

Looks good to me. Like you said maybe move tap.

[maple flats]

If it was in bad wood you would get little or no sap. Verify it is a maple. When drilled, were the shavings white? You possibly need to clean the pan even better. My best guess is that it is not a maple.

[happy thoughts]

Your pic is a maple- opposite branches and maple shaped leaves. What are your pots made of? Reactive metals like iron, chipped graniteware, and aluminum can impart flavor to the syrup. That's why the preferred pot material is stainless steel.

How did you clean the jugs?

Did you filter the sap or syrup at any stage? Possible off flavor from filtering materials.

Does everyone describe the taste as musty? What did you eat or drink before tasting?

How and for how long are you storing sap?

Last thing I can think of is burnt niter. If you're only boiling 1 Gal at a time in a wide pot you must be down to mm deep by the time you get to syrup. A Gal of sap will make about 6 TBLS of syrup if you're lucky, about enough for a thin layer in an 8"- 10 " pan

[reganzzzz]

The pots are all stainless steel.
I didn't clean the jugs -- bought distilled water at CVS in gallon plastic and just poured it out and airdried the container for a few days.
Tried some where I filtered the sap with coffee filters and some where I didn't -- no change.
Everyone thought it's musty, including the guys at the sugar house.
I can mail anyone here some in a tiny ziploc if you want to smell.
All sap used within 5 days, one was used the same day it was collected
It's not burned -- the smell emerges just as it's turning golden and starting to boil after hours of steaming, so there's still a half-inch in the pan.
I burned one on purpose to see if that would change anything, but the musty smell is still there under the burned smell.

[COMSTOCK MAPLES]

Sorry I thought you were adding a gallon at a time. To batch boil you should use min of 5-10 gallons then filter syrup. One gallon is not enough sap. Stock up more sap.

[325abn]

I can't see boiling down 1 gal of sap to syrup without burning it.

[happy thoughts]

The pots are all stainless steel.

Burned syrup is not the same as burned niter so I still have to wonder if that could be the problem especially when processing such small amounts. Also, five day old sap is getting a little long in the tooth even if kept refrigerated. What are you storing it in and at what temp? I can't think of anything else that could possibly cause an off flavor other than the sap itself.

[DrTimPerkins]

... then a smell emerges that is best described as musty.

It sounds like an off-flavor called "metabolism" to me (assuming it didn't come from your equipment or your filters). It happens sometimes, especially with early-season syrup, and is often described as "musty" or "woody".

[lastwoodsman]

Is that a Norway maple (Acer Platnoides) your problem could lie there.
Woodsman

[MidMichMaple]

Is that a Norway maple (Acer Platnoides) your problem could lie there.
Woodsman

From looking at the picture... Maybe I'm crazy, but the one leaf that I can make out clearly has that extra wide Norway Maple look to it. Obviously it's almost impossible to tell considering the angle and distance the pic was taken from, but when I was a "novice" maple nerd I used to get Norways and Sugars confused. Now I can almost literally spot a Norway from a mile away.

BUT: Norways don't normally get nice color like the tree in the pic, so maybe it's my imagination. Like others have said, maybe the problem is the sap that sat around for 5 days. That seems like a potential problem to me.

[reganzzzz]

Here's another photo where the leaf shape is clearer:

http://experimentsinformandfunction.tumblr.com/image/79963530125


I'll add it to my first post as well.

[happy thoughts]

I think Dr. Tim gave you the best answer -early metabolic sap. If that's the case I think your later sap should be better. As for species of maple. I don't tap Norways but know somwone that does and makes decent syrup from it. I think a few others on this forum tap Norways as well and I don't remember anyone complaining about off flavored syrup.

PS- a pic of the trunk and bark would help make ID easier. Or check a tree ID guide to see if you can pin down the species better.

[MidMichMaple]

Here's another photo where the leaf shape is clearer:

http://experimentsinformandfunction.tumblr.com/image/79963530125


I'll add it to my first post as well.

Ok, that is definitely a sugar maple. At least in my humble opinion, that picture removes almost all doubt.

[reganzzzz]

If it's metabolism, do I just keep collecting sap and discarding? When should I try again to see if it's better?

[lpakiz]

Reganzzzz,
Are you washing tanks or equipment with soap , or disinfecting with some sort of sanitizer?
My mantra is " wash with sap, rinse with sap" after I had random issues with off-flavor syrup. Now, no more problems.

[happy thoughts]

If it's metabolism, do I just keep collecting sap and discarding? When should I try again to see if it's better?

I'm not sure. And after thinking about my reply earlier, I'm not even sure if it will get better. Hopefully Dr Tim will stop in again with some answers for you.

That said, with late metabolic sap (buddy sap) you can usually smell an off smell soon after boiling. To me it smells like hot wet cardboard. Not sure if early metabolism will have the same profile. There is also a way to remove the off flavor of buddy sap sometimes by bringing it to a high temp, over cooking it, then bringing it back down to correct density with water. That doesn't always work and I wouldn't try it on such small quantities that it seems you are making. But if you stockpile enough syrup over time it might be worth a try. Again, not sure if this will work for your syrup. Dr Tim will have better answers as I know he has conducted some research along these lines. Hopefully, he'll stop in again.

[Clinkis]

Thats smell sounds like sap thats gone bad. Are you sure your sap isn't spoiling before you boil it? Are you storing it for very long before u boil it or in a warm environment? Have you actually tried finishing it right down close to syrup and see if it sweetens up? Sometimes it won't get very sweet smelling or tasting until it gets closer to syrup stage?