Off-taste sap/syrup

[tommymc]

I've been backyard sugaring for over 20 yrs. Currently, I have 8 buckets out around the yard. I have a small arch with an 18" x 26" pan and usually make 1 or 2 qt at a time. For the last two years, I've had random boils that resulted in an off-taste product. The syrup is still sweet, but smells more like corn than maple. I'm still trying to get to the bottom of it. I haven't really made any changes to my process except cutting back a little.
I just tapped a few days ago and collected my first sap. My larger trees had some very clear sap measuring 4% or so. I checked the smaller trees at the other end of the yard. One bucket just had a little squirt like the tree had pissed in it. Discard! The other 4 buckets had a small amount of darkish sap. Usually I mix that in with the clear sap, but this time I brought a gallon in and boiled it down on the stove. Sure enough, I got that off-taste syrup. I have not yet tried the same with the clear sap. (It's sitting in my "bulk" plastic trash container, buried in a snowbank until I get enough to boil)

So I'm wondering if anybody else has had similar experiences? Is there such a thing as a bad tasting tree? Let me be clear.....most of the syrup still comes out great. It's just one or two qts that end up off-tasting. These are a mix of red and sugar maple. Any other thoughts?

[Jeff E]

When you tap are you getting only white sap wood, or maybe getting into stained or heart wood of the tree?

[DrTimPerkins]

Stained wood itself does not transmit sap (even under vacuum), so you are likely either tapping into a rotten section of wood (which could have some moisture in it), or are getting rainwater washing down the truck running off the spout into your bucket.

[tommymc]

Thanks for the replies.... So I'm always careful to avoid tapping in close proximity to old scars. The wood is definitely clean and fresh. Jeff, I hadn't heard about heartwood. Are you suggesting that I might be drilling too deep? The "suspect" trees are all younger / less diameter. Could you elaborate on heartwood?

Dr Tim, these appear to be healthy trees and the wood "looks" fresh. This week at least, rain wouldn't have been a factor. If rainwater did get in, what is the concern.....bacteria from the trunk? Just thinking it through, I can't think how my method of tapping has changed in the last 20+ years, yet this is a recent problem. Surely rain must have gotten into the buckets many times in all those years.

Really, the one difference that I can think of is that I've scaled back. At one time, I tapped my neighbors trees (big old sugar maples) and shared the syrup. With fewer taps, one bad one would be contributing proportionately more. Just grasping at an explanation......

[DrTimPerkins]

If rainwater did get in, what is the concern.....bacteria from the trunk?

Crap from the bark...dirt, fungi, tannins from the bark can all wash in with rainwater. Such "stemflow" is often discolored yellow or brown and can taste bad.

Solid stained wood does not yield sap. Rotten wet wood can yield liquid (not sap). Why more this year? Who knows...maybe just bad luck.

Lastly and before someone else chimes in..."trash" containers area not appropriate for collection/storage of sap. These will leach nasty (non-food grade) chemicals into sap, which get concentrated into syrup. I suggest you investigate getting a real food-grade tank of some sort.

[tommymc]

So I did a quick(ish) test this afternoon. I boiled samples of sap from the suspect trees individually in a sauce pan, and all tasted okay. BTW today's collection was all clear sap. So basically, I don't know where that leaves me.

I will look into getting another container for bulk storage. Any suggestions of where I might acquire a suitable replacement locally (Middlesex VT) at a reasonable price? Tractor Supply has a 20 gal barrel that they say is food grade, pretty similar to what I'm using now....which works well for me. Would that be a good choice? https://www.tractorsupply.com/tsc/product/rubbermaid-brute-container

[Bruce L]

Here’s another thought,taste your sap from the individual buckets,just maybe a tablespoon full,you might find your trees that yielded “ darker sap” as you put it did leach in something. If you get an off flavour in the sap it will be concentrated in the syrup

[tommymc]

Regarding the plastic trash barrel I use for storage. It's been used exclusively for this purpose since I bought it 20+ yrs ago and is marked #2 HDPE. I thought all #2 HDPE is food safe, is that not so?

[Super Sapper]

#2 HPDE is not all food grade. It can be made with recycled plastic that who knows what it had contact with. Food grade will be marked and is made from virgin plastic and uses a nontoxic release agent.

[bigschuss]

Since this is the same barrel you've ben using for 20 years it would seem not t be the source of your off-taste. Probably still should replace it. But probably not the problem.

Here's a link to a guy I buy food grade barrels from in Bennington. Not sure how far away you are from him. Nice guy. He's got all kinds of sizes and shapes of food grade barrels.

http://www.barrelsforu.com/

Good luck with your sap/syrup. Other than what's been said, it's hard to think of what could be happening without actually knowing all the details of your set up.

[tommymc]

Since this is the same barrel you've ben using for 20 years it would seem not t be the source of your off-taste. Probably still should replace it. But probably not the problem.

Here's a link to a guy I buy food grade barrels from in Bennington. Not sure how far away you are from him. Nice guy. He's got all kinds of sizes and shapes of food grade barrels.

http://www.barrelsforu.com/

Good luck with your sap/syrup. Other than what's been said, it's hard to think of what could be happening without actually knowing all the details of your set up.

Thanks for the link. It's 2 hrs south of here, but we have friends in CT and make occasional trips in that direction. You're correct that this isn't the source of my problem. In my test boils of suspect sap, the sap want straight from the bucket to the stove....bypassing the bulk container.

On Saturday, I repeated my test mini boils (in saucepans) of the handful of suspect taps....the ones that had previously produced off tasting syrup. There wasn't a lot of sap, but it was clear this time, and tasted fine. I ultimately added it to the rest in the bulk container, and boiled 1.25 qt of really light syrup which tasted fine. Yes, this is backyard, and I measure in quarts.

At this point, what it comes down to is that all my taps have produced good sap. A few of them also gave me bad sap. I have to figure:
1. Whether the sap is being contaminated in the bucket or coming out of the tree that way
2. How to reliably identify off-taste sap. I think it's too dilute for me to taste the difference in the bucket. Is color a reliable indicator? I'll have to test that with more mini-boils.
3. I wonder if this is common, but more pronounced because I've scaled back. It does seem to coincide with that. A little contaminated sap mixed with 15-20 buckets isn't going to be as pronounced as the same amount mixed with 6-8