Off flavors/aromas, sources, and remedies

[bryankloos]

Hi all,

I just opened up a bottle of syrup from last season, and was reminded of a slightly off aroma that I encountered last year.

I collect from mostly reds, RO overnight and then boil the following day. All syrup drains off the evaporator through a pre-filter and then a synthetic cone filter into clean 5 gal buckets. I then store at RT until I finish/bottle in the kitchen. On some batches I run through a CDL 9" vac filter with DE, other batches I don't filter at bottling.

Strangely enough, last year I noticed some off aromas from the syrup after running through the CDL vac filter. As in, if I stuck my nose over the freshly filtered hot syrup it had a peculiar funk. I washed the filter well prior to use, and I use food grade DE from Bascom... I recall the smell being associated with the filter, and not the unfiltered batches, pointing me towards the filter as the culprit.

Any ideas what this could be? I'm not that good at describing smells... maybe biscuity or cardbaordy?

One area of my production chain that may need to be upgraded is storage in the 5 gal buckets after the evap and before bottling. If they sit at RT for a week or two, maybe they are growing some bugs, or yeasts. They are covered during storage, but sit open while draining off the evap. Maybe I should probably start storing these in the fridge prior to bottling???

Anyhow, where should I focus my efforts on avoiding any smells/flavors this year?

All help is appreciated.

Thanks,

Bryan

[maple flats]

Tell us your filtering process, step by step, including temperatures as best you know them.

[tpathoulas]

Bryan, You're scaring me a little! I have been looking at getting the CDL Vacuum filter. Filtering has always been an issue for me. Mainly the time it takes to filter through cone filters with pre-fiters and the mess it makes as I try to change the hot profilers.
Last year was especially a difficult filtering season and I apptribute most of it to the sap the trees provided. I filter about three times prior to bottling. Once coming off my evaporator, second after getting to proper brix, and lastly I filter through a paper filter after reheating to bottle. Last year when bottling my hot syrup was nice and clear. as it cooled I started to see a cloudiness. I decided to store in half gallon mason jars and wait for everything to settle. This fall I poured out the clear syrup and heated to 185-190 for bottling. The sediment left in the bottom was very dark, almost black with an off scent. The syrup tastes good with a little off flavor but nothing super noticeable and maybe not noticeable to most people. Nothing grew in the syrup and last bottles I have left are nice and clear. I believe whatever this dark sediment is, is related to what minerals came from my trees. I have never seen it before and I have not changed my processing except I added an RO but none of my other batches made this sedimentonly the last of the season. I'd love to hear from anyone who has an idea to my problem.
In the end, do you like the vacuum filter? Do you think the smell was from storing the filter or was it brand new?

[bryankloos]

My filtering process is as follows:

Off the evaporator I filter through a cone prefilter and synthetic wool filter which collects in a 5 gallon food safe plastic pail.
I then store this syrup covered until bottling, which can be between 1+ weeks. This storage takes place in my basement, probably at about 58F.
I then transfer this to a large stock pot on the stove and bring to a boil, achieving my final brix, skimming and floating scum, then through the CDL 9" as per manufacturers instructions, vac filter with DE and then bottle out of the CDL into glass or plastic keeping temps at appropriate bottling temps.

All pretty straightforward. I guess its either in the syrup, from the plastic pails, from the DE, or from the CDL.

I like the CDL vac, but to be honest it bogs down after a minimal volume of filtering. Its nice because I can bottle directly out of it, immediately after the filtering, but successive batches can be troublesome. I find myself breaking is down, clearing the DE cake and filter, then reassembling for the next round which is a nuisance.

My vac tube from the shop-vac was aslo flimsy, and when hot wold collapse under the vac. I purchased a new smaller diameter, rigid tube to use this year to increase efficiency of the vac.

Thoughts?

Syrup coming off the evap never have off smells. I'm not sure if they are present on the stove before I transfer to the CDL, but they are clearly present when I smell the collected vac-filtered syrup in the botom of the CDL post vac.

[johnallin]

The plastic pails may be your culprit.

I would try stainless, especially if it’s going to sit for any length of time.

Storing near-syrup at 58 +\- degrees for a week isn’t helping either IMHO.
Hope you have a great season...getting closer by the minute.

[bryankloos]

Sounds fair.
I'll try to get away from the plastic, and I can also keep the syrup in the chest fridge prior to filter/bottling.
Does this sound good, and where can I source stainless containers to hold the syrup for storage?
Thanks!
Bryan

[maple flats]

A couple more questions, are the pails specifically "food grade" , were they cleaned completely? and you say you need to remove the filter ccake and start again. How much DE are you using per gallon or what ever amount you do as a batch. Do you heat the syrup to about 185 to filter it?
I also wonder if you are using too little DE and if you still have 180+F as you bottle.
In my traditional filter press, even if I start with 205 or hotter, I still need to add some more heat before I can bottle. When I filter I add (early season) 1.5 cups DE in about 2.5-3 gal syrup, mix well, then filter. If a second batch is run right after that (and it usually is) I draw about 6 gal syrup, add another 1.5 cups DE, mix well and filter. I keep repeating that until my entire batch is filtered, either into a SS barrel or the WJ bottler or both. I often fill a barrel, then the rest goes into the bottler. I do not fill a barrel in 2 separate batches, I only fill one if I have enough to fill it fully. Late season syrup gets more DE. If you lose the ability to filter because it stops moving, from experience that means you used too little DE, unless the space is full of filter cake. What happens when you use enough DE, is a filter cake (a blend of DE and niter) keep building and it keeps allowing more syrup to pass. When a cake forms that won't let syrup pass, but the filter is not full to capacity, it is because there is too much niter (sugar sand) in relation to the amount of DE.

[johnallin]

Sounds fair.
I'll try to get away from the plastic, and I can also keep the syrup in the chest fridge prior to filter/bottling.
Does this sound good, and where can I source stainless containers to hold the syrup for storage?
Thanks!
Bryan

The fridge would be a great improvement.
Stainless stock pots in 3-5 gallon size should be easy to source at a local store or online.
Just don’t think plastic is your friend for storing hot syrup off the evaporator for any length of time.

[mainebackswoodssyrup]

The fridge would be a great improvement.
Stainless stock pots in 3-5 gallon size should be easy to source at a local store or online.
Just don’t think plastic is your friend for storing hot syrup off the evaporator for any length of time.

I don’t know if there is anything special about the plastic jugs that maple suppliers sell other than being food grade but I’ve never see an issue with them whether it’s hot syrup stored for 2-3 hours or 2-3 years...assuming they were properly hot packed.
Correction- re-read this post and random 5 gallon pails could certainly be a problem. Recycled plastics and several other factors could play in to for sure!

[bryankloos]

The 5 gallons pails were purchased at Home Depot, and are listed as food grade.


https://www.homedepot.com/p/Leaktite-5-gal-70mil-Food-Safe-Bucket-White-005GFSWH020/300197644

With the vac filter, I boil on the stove, bring to final brix, add DE (~ 2 cups/4 gal) and then run through the vac filter. Maybe I need more DE.
The filter has a fixed capacity, I think 3 gallons, but one needs to run the syrup through in a couple batches at the top cant hold the total volume. So I do it in a couple batches as its just me...
I don't loose too much temp, and bottle at 195 ish.

[mainebackswoodssyrup]

We have 2- 15 gallon stainless “turkey fryer” pots used solely for syrup. Definitely try finding something stainless to store in until you are ready to bottle or hot pack in some sort of container. Cover it and don’t let it sit too long, a week or two tops. Sounds like you may still be fine tuning the DE amount, not much help because I have no experience with vac filters. But generally speaking, you’re not going to filter out an off flavor, there’s something else going on.

[buckeye gold]

One more question, did you try a new filter? Many off flavors don't show up until syrup is cooled, so it may still be in your system before syrup.

[bryankloos]

I will use a new filter this season, actually a couple.
Last year I would limply rinse it clean with hot water and let it air dry.
Is there a better method for cleaning the synthetic cones?

[buckeye gold]

I put my filters in the clothes washer on hot water, light cycle and no soap. They come out really clean and I have never seen it damage them. Someone will most likely tell you not to do this, but I do it anyway. Some washers have a gentle cycle instead of light duty. I could never get them as clean rinsing with hot water. I have orlon filters.

[maple flats]

I used to clean my pre-filters in the washing machine too, ran 2 full cycles, no soap, hot water. Now I'd even question that.

[LMP Maple]

Couple of thoughts, one can you finish the syrup in the evaporator and skip the process of bringing it up to brix in the kitchen? This would eliminate the need to store the near syrup and you would be dealing with a finished product which would store easier. This may not be an option but thought I would ask.

Also I was thinking if it was me and I could not finish the syrup in the evaporator I might consider using the filtering container to draw off near syrup into without the filter in it if it is big enough it is stainless after all. You could then transfer into whatever pot you are using to finish the syrup clean the vacuum press container and filter the syrup once it reaches the right brix using your press as you do now and bottle it etc. Just thinking about ways to get the plastic out without having to buy another stainless container.

I would agree that the plastic and length of time are likely the source, but I cannot speak on the DE as maybe being an issue. You can certainly find all kinds of stainless draw off containers at the sugaring stores. They are expensive but its a one time purchase. I currently draw off into a 6 gallon cylindrical stainless tank. I filter directly off the arch into a wool filter with pre-filters. The sailors hat method has been a game changer for me. Learned about that on this site! I two have been very intrigued by the CDL Vacuum press. This makes me a little worried about making that kind of investment. Please keep us informed. Good luck!

[johnallin]

Just a thought but I believe the Vac presses could introduce any fumes or pollutants that may be in the surrounding area.
By design, syrup is pushed/drawn through the filter by air trying to overcome the vacuum. From the videos I’ve seen, filtering is complete when nothing but air is being drawn through the filter media. If you’re in a musty basement or shack, is that being infused into your syrup? Maybe, maybe not.

[bryankloos]

Vac filtering and bottling takes place in the kitchen, so probably not an issue relative to fumes.
I do basically finish on the evap, but need to bring back up to temp to bottle, hence the reheat/brix final adjustments in the kitchen.
The DE is food grade and from bascom, so I think its the same as everyone else is using. The vac filter is for my decorative bottles that I want crystal clear. If I were in plastic jugs I'd skip this all together.

Let me ask about scum and scum skimming during boils. What is this scum, and is it possible that it is imparting off flavors into my syrup?

I've been told its niter but I wonder. Its light beige and floats on top of the boil. I get it every time I boil... The scum has a smell but I've never tasted it.

I guess a good exercise would be to take some of the finished syrup into bottle directly from the evap. Then take some of the same syrup and go through the store/reheat/vac filter to see if there is a difference. Kinda of an A/B experiment.

Either way I'll buy a couple 20qt stainless stock pots for storing after boils. They are cheap enough and I can use them for other purposes off season.

[therealtreehugger]

Hi Bryan - A thought on the scum - could it be a result of defoamer? Are you using a lot? a different type? Your description reminds me of foam in the evap. or could it maybe be a result of putting hot syrup from the evap into plastic buckets? I use the same plastic buckets, from Home Depo, but only for sap collection, and RO-ing. I have a 6 gal ss "lobster pot" I use to finish, and then last year bought another ss pot online, from a site that has brewing supplies I think, with a spigot at the bottom! I finish in the lobster pot, then filter into the spigot pot, then it goes immediately into the bottle. I do not have a vac filter.

[bryankloos]

I do use defoamer in the evap. I still get beige foam/scum that builds up on the sides of the channels at the fluid/sap line.
I’m starting to think that maybe this is the source of funk.

The defoamer I use was from bascom, sold as defoamer. Maybe I should switch to straight canola oil?

I try to skim the scum with a SS spoon as I boil. Maybe I would benefit from a good skimmer?

I’m still curious what the scum is. I need to take some photos this year, assuming it’s present.

[Pdiamond]

Bryan, I just wanted to add my 2 cents. I finish on my evaporator or maybe a little over. when the auto-draw empty's it goes into a 5 gallon plastic pail. This may be in the sugar house for a few days before I finish and bottle in my kitchen. I do use a filter press which is different than the vac. filter. Last year I used 3/4 cup DE per gallon of syrup. I don't think its your use of plastic pails causing the problem.

[18mile]

Hi, I would be suspect of anything the sap or syrup is stored in. I would also question the length of time in storage for both. If you are using food grade d.e. there should be no issues with the filtering. It is also possible to get a batch which naturally develops a off flavor.

[DrTimPerkins]

Bryan...you mention that you noticed it a bit last spring. When during the season did you notice it (early, late, middle)? Was the syrup light or dark in color and flavor (the syrup flavor, not the off-flavor)? Did it affect your whole crop, or just a part of it? Did you use the filter all season, or just part of the season (and which part)?

[therealtreehugger]

I do use defoamer in the evap. I still get beige foam/scum that builds up on the sides of the channels at the fluid/sap line.
I’m starting to think that maybe this is the source of funk.

The defoamer I use was from bascom, sold as defoamer. Maybe I should switch to straight canola oil?

I try to skim the scum with a SS spoon as I boil. Maybe I would benefit from a good skimmer?

I’m still curious what the scum is. I need to take some photos this year, assuming it’s present.

I know the scum of which you speak!
I also have a ss slotted spoon to try to take off some. I used to fling it off the spoon as waste, until I realized how good it tasted! I have a feeling it is extra protein in the sap? And it does leave a small "scum line" in the evaporator too. I get it the most in the early and middle channels of the pan, not as much in the channel that is closest to syrup.

[bryankloos]

Bryan...you mention that you noticed it a bit last spring. When during the season did you notice it (early, late, middle)? Was the syrup light or dark in color and flavor (the syrup flavor, not the off-flavor)? Did it affect your whole crop, or just a part of it? Did you use the filter all season, or just part of the season (and which part)?

Good questions, of which I wish I had clear answers.

Id say I more noticed it when I started using the vac filter, but this was probably early in the season. I'm pop open a couple bottles from early (lighter product) to later in the season (darker) to see if I can see a difference. I'll also check vac filtered vs not vac filtered to see if it follows any pattern.

I will take better notes this season and pictures as well.

[DrTimPerkins]

To the list of possible issues you could add: musty (generally from filters) or metabolism (from the tree). Metabolism is one of those things you often don't notice much during the season, but it is more noticeable later on. Earthy, musty type of off-flavor. Some associations sell the UVM off-flavor kit so producers can have a reference for what the flavor might be.

https://www.themaplenews.com/story/off-flavor-syrup-reference-available/137/ This was the "mother nature" off-flavor kit.

I believe Mark Isselhardt (UVM Extension) is working on the second kit, which I think was going to be "processing" off-flavors.

A good description of maple flavors and off-flavors here:

https://www.ohiomaple.org/documents/Maple%20Off%20Flavors%20-%20tasting%20maple%20-%20Copy.pdf

[bryankloos]

I’m leaning toward metabolic changes, probably from sitting in my plastic pails at RT for greater than 2 weeks prior to bottling.

I will store in stainless, at 35F this year between coming off the evaporator and bottling.

I will ensure my filters are cleaned more thoroughly.

I’m also going to avoid the second kitchen boil, except for samples that I want to run through the vac filter (for decorative glass bottles) and just bring up to bottling temp to avoid more niter production.

With all these changes I’ll take notes and report back with observations.

I’m hoping to nip this in the bud.

[steve J]

If you have a Christmas Tree Shop you will find you can buy 16QT and 20Qt Stock pots at a reasonable price.

[DrTimPerkins]

I’m leaning toward metabolic changes, probably from sitting in my plastic pails at RT for greater than 2 weeks prior to bottling.

Metabolism is a naturally occurring off-flavor. If that is what it is, you didn't cause it. It came from the tree. It could be "sour sap" as well, which would be fermentation of the sap or partial syrup. Totally different thing....sour sap tastes fermented...is kind of "fizzy" on the tongue.

In any case, good luck in solving the mystery of what it is and eliminating it.

[therealtreehugger]

Metabolism is a naturally occurring off-flavor.

Dr. Tim - when you talk about metabolism - is this the same thing as getting the "buddy" flavor/taste/ whatever at the end of the season? And I think I read somewhere which trees will bud first - reds or sugars - but can't remember which.
Thanks!

[DrTimPerkins]

Dr. Tim - when you talk about metabolism - is this the same thing as getting the "buddy" flavor/taste/ whatever at the end of the season?

No, metabolism and buddy are two very different naturally-occurring off-flavors. Metabolism is most frequently found early in the season, especially in light-colored/flavored syrup -- buddy is an end-of-season phenomenon. Both are (most likely) due to amino acids in the sap that produce the off-flavor when boiled, but they are caused by different amino acids. Metabolism is from nitrogenous amino acids -- buddy is from sulfur-based AA. In both cases they can't be detected until the sap is boiled. Some people can't detect metabolism off-flavor (or smell) very well....others are very sensitive to the flavor (probably this is genetically based). Most everyone can taste buddy. Metabolism happens only occasional, but some sugarbushes are more prone to the problem. Buddy will happen every year if you collect really late-season sap.

[therealtreehugger]

Dr. Tim - Thank you very much for the clarification! I learn a lot from you, and everyone else here! Thanks!

[Sugarmaker]

Like Dr Tim, I was thinking this might be Metabolism also. It took me a while to figure it out. Luckily I had a freind who is a chemist and he was doing work to find out why his syrup smelled funny and tasted funny.
During that same time And several times since I have made metabolic syrup. Yes its from the trees nit you.
The thing is did you ever make good syrup? If the answer is yes then you have to see what changed in your process. If nothing. Then this flavor and aroma variant from the trees could be the issue. Lots written about it. But it is illusive. Can occur in varying degrees at any time in the season.
My worst case was very late season tapping. The sap even tasted a little flat.
Cardboard flavor to really bad mr YUK taste is the range. You can smell it in the steam as it boiling too.
Hope this helps a little. Be aware this may not be your problem. You need to try to rule out any thing that may have changed in your process too. Sometimes it takes a while to find the answers.
Regards,
Chris