What factors makes syrup darken as the season progresses?

[Diesel Pro]

Curious why the finished product darkens teh later you go and what can be done to prevent this?

[Thompson's Tree Farm]

As the bacteria in the spout and tap holes increases, it feeds on and changes the sucrose to fructose and glucose (only a small percentage). Glucose and Fructose brown at a lower temerature than fructose thus a darker syrup.

[red maples]

I agree bacteria yes but I thought that in that case it was a build up of bacteria from holding sap too long. Isn't the tree it self giving a higher % of fructose and glucose and less % of sucrose? and yes Fructose carmelizes at a lower temp then sucrose. because if that were the case the syrup would never lighten up again later in the season as it does in some years. the light syrup is mostly sucrose and the darker syrups have alot more fructose and glucose. Which is why in sometimes the Batch or kettle syrups can take on the flavor of a strong caramel or mollasses. which comes form the fructose. It is also the reason that birch syrup is so dark and strong because of the high amount of Fructose and lower amount of sucrose in the birch sap.

[DrTimPerkins]

Isn't the tree it self giving a higher % of fructose and glucose and less % of sucrose?....the light syrup is mostly sucrose and the darker syrups have alot more fructose and glucose.

The vast majority (99.5%+) of the sugar coming out of the tree is sucrose. Microbes cleave a fraction of the 12-C sucrose molecule into the 6-C sugars, glucose and fructose (invert sugars). Even heavily contaminated sap will produce syrup with a fairly low quantity of invert sugars....less than 5%, and quite frequently less than 1-2%. It really doesn't take a lot of invert sugar to cause the syrup to darken (and develop strong flavor).

[GeneralStark]

I have been using a glucometer this past season for testing sap invert sugar levels. I also use it for testing syrup prior to making confections as I blend syrups to optimize their resale value.

I share equipment (ro and evaporation) with two other friends. Their tubing system is old and mine is new. Our sap mixes in a day tank inside the sugarhouse that we use for pumping to the second floor storage tanks. I have observed low invert reading in the sap coming from my system, with higher readings coming from their system on the same day. This greatly depends on temperature and other factors however. The more substantial the sap run, the more similar the invert reading will be from the two systems. The other challenge with our system that often leads to darker syrup is the day tank that is in the heated sugarhouse. If the sap stops running overnight, the sap will sit and begin to ferment, then when it starts running again in the morning, the fermented sap (high invert) gets pumped upstairs and essentially contaminates the fresh sap. Regardless of how much sap we get that day, when we process we end up making dark amber or even darker. We really only make medium or fancy when we get substantial sap flows that don't allow the sap to sit in the day tank for long.

As Dr. Tim said, it does not take much invert to lead to dark syrup. The key to minimizing this is not letting your sap sit for long, especially as the weather gets warmer, and to closely consider your sap collection system. Older mainlines hold more microbes and can begin the fermentation process as sap is flowing. Storing sap(even small quantities) in heated spaces can quickly lead to high invert levels, especially if the sap came through high microbe tubing and mainlines. The difference in readings between the older tubing system and the new on certain days is quite impressive.

Dr. Tim: My understanding is that invert sugar is the primary factor related to syrup darkness and flavor. Is this all there is to it? Can you direct us to some resources to better understand this relationship. My partners seem to think that invert sugar is possibly related but that syrup darkness has more to do with certain mythical factors like soils, tree chemicals, and other undetermined factors. I think this is an easy thing for a sugarmaker to understand and control, but it seems that many still feel that this is more voodoo that rational thinking.

[Diesel Pro]

I had my April 13 batch graded and it was just getting to the darker end of medium amber. April 20 batch was noticeably darker, but stil not bad.

What I have seen in the stores is very dark almost black. I think I would be embarassed to put that in a glass bottle. Selling price $12.95/qt and it's locally made.

We've done batch processing on weekends so far. I keep the sap out of the sunlight as much as possible and try to keep it cool, but it seems to hit 50°f in the cabin even with the heat off.

Another question: Is it better to store at 2.5% or semi concentrated to say 8% or does it even matter?

[DrTimPerkins]

My understanding is that invert sugar is the primary factor related to syrup darkness and flavor. Is this all there is to it?

Invert sugar levels from microbial contamination is not the only factor involved, but is certainly the predominant factor. Prolonged heating or reheating can also cause syrup darkening.

[GeneralStark]

How about the condition of the pans? ie cleanliness and/or niter buildup.

[DrTimPerkins]

How about the condition of the pans? ie cleanliness and/or niter buildup.

Yes, there are a host of other minor factors. They typically affect the syrup color/flavor through caramelization. Both pan cleanliness and niter would affect this process.

Some of you have experienced caramelization of sucrose (if you scorched your pans). You know that it turned dark (black) and got very aromatic (burnt smell and taste....smoke may have been involved). That is an extreme (and undesirable) example of caramelization. The primary reason that invert sugar causes darkening is that fructose caramelizes at a considerably lower temperature than sucrose (or glucose). Keep the invert level (especially fructose) low, and there will be relatively little darkening or flavor development. There are several ways to keep invert levels low, but the main (and legal) way is to filter the sap (to remove microbes), keep it cold (to slow microbial growth), and process it quickly (to keep the critters from multiplying too much).

[Bucket Head]

Tim,

What percentage of the "critters" does a 5 micron filter catch? Is that the best filter for sap? I know pool sand filters are used for sap- how do they compare to the cartridge style filters? Do you filter the sap at Proctor, and if so what do you use?

Steve

[DrTimPerkins]

What percentage of the "critters" does a 5 micron filter catch? Is that the best filter for sap? I know pool sand filters are used for sap- how do they compare to the cartridge style filters? Do you filter the sap at Proctor, and if so what do you use?

It depends on a lot of things, but 5 micron will catch a lot of what is in sap. What is "best" will vary quite a lot with the size and style of operation. I have no experience with pool sand filters, so can't comment on them. We use the Lapierre pressure filters with a 10 micron cloth, followed by UV treatment. Those filters work reasonably well until the end of the season, at which time you can't change the filters fast enough to keep up with it. We will be looking at different sap filtering methods more in depth this summer and fall.

[Diesel Pro]

Well I learned a lot my first year mapling, but I never did manage to get darker than probably the lighter level of dark amber. We made "batches" each weekend using 100-300 gallons of sap depending on the run and nothing left the pans until the batch was done. Next year I'll start to experiment with drawing off.

The biggest mistake I made was running the RO then holding this concentrate a couple of days for boiling. It definitely was starting to ferment, but came out just fine.

In the end none of my syrup came out as dark as what I've been seeing on the shelves. What I understand is that darkness is primarily a factor of cleanliness. So why would one desire to make dark?

Here is a quote from a web site of a semi local producer:

"All of the pure maple syrup sold on our web site is U.S. Grade A dark amber, unless otherwise specified. We find that most people enjoy dark amber because of its pleasant flavor. It is not too strong and not too weak, just the right amount of that pure maple flavor."



Now I've been getting compliments that mine is much lighter color and people are preferring this to the dark. I suppose it's all a matter of personal preference, but are the guys that are touting dark as "consumer preferred" just creating a marketing tool for a lesser quality product?

[happy thoughts]

What I understand is that darkness is primarily a factor of cleanliness. So why would one desire to make dark?

.....<snip>.....

Now I've been getting compliments that mine is much lighter color and people are preferring this to the dark. I suppose it's all a matter of personal preference, but are the guys that are touting dark as "consumer preferred" just creating a marketing tool for a lesser quality product?

I don't think it's a marketing tool. In general I prefer darker syrup but also enjoy the light syrups I've made which have always had a more delicate taste, more vanilla in nature than maple. Many people prefer dark because of it's more "maple" flavor and from what I've read, certain bacterial strains are known to enhance/improve that taste along with darkening the color through carmelizatioin. Bacterial action on sucrose can create more invert sugars that more readily carmelize during boiling. Depending on your taste preferences, the presence of bacteria can be a good thing much like certain microbes give specific cheeses, bread, and wine their flavor. That's not to say that all dark syrups will taste the same or taste better than light or that cleanliness should be avoided :).

[Diesel Pro]

Basically, if I understand correctly the way that they would "get it dark" would be a controlled or semi controlled fermentation process? In crude terms they "piss it up" with bacteria that convert the sugars then cook them off and kill them using as part of the finished product?

[happy thoughts]

Basically, if I understand correctly the way that they would "get it dark" would be a controlled or semi controlled fermentation process? In crude terms they "piss it up" with bacteria that convert the sugars then cook them off and kill them using as part of the finished product?

I'm not sure I'd call it controlled. Syrup generally tends to get darker as the season progresses with the darkest syrups usually produced at the end of the season. Some things are out of one's control like the age of taps and weather conditions which contribute to microbial growth. And microbial contaminants can just as easily be bad ones such as those that cause ropy syrup. Also by law, nothing can be added to syrup other than defoamer, salt and water so to control the process by adding bacteria would be illegal. But that doesn't mean you can't let nature take it's course sometimes if darker syrup is what you're after.

[michiganphil]

Basically, if I understand correctly the way that they would "get it dark" would be a controlled or semi controlled fermentation process? In crude terms they "piss it up" with bacteria that convert the sugars then cook them off and kill them using as part of the finished product?

First off...dark syrup is not necessarily inferior, it just has a slightly different flavor. If you say it's inferior, then you would be saying those that use red maples instead of sugars or wood fired evaporator instead of gas are making inferior product. It's just different.

These commercial producers don't "get it dark". Dark syrup comes naturally as the season progresses, and tends to outweigh the light. Producers will blend their light and medium syrups with some dark to make their preferred grade. A lot of them are not even producers, but bulk packagers that buy it by the barrel, blend to their specifications, bottle and re-sell.

I think there are a few reasons:
1. from a quality standpoint, it is easier for the producer to keep a uniform product from bottle to bottle and season to season.
2. how confusing would it be for the consumer to see variations of color in the bottles on the shelf(there can still be color variation within a specific grade), or see "more mapley" "less mapley" or "kinda mapley" on different labels. The producer would have to spend more on different labels and marketing to educate the consumer. The grocery stores would have to keep inventory of more products as opposed to just 1.
3. most consumers seem to have a predetermined idea of what maple syrup should look like (that perception being driven by the fake products like Aunt Jemima's), so grade A dark seems to outsell lighter grades in the grocery store.

This all makes sense if you market for wholesale to retail outlets. Now if you're selling from the shack or at farm markets, I say educate all the people you can. Let them decide what they like. You will probably end up with more repeat customers.

[RileySugarbush]

Occasionally when we are making very light syrup it has such a mild flavor that we pour it slowly back into the float box and run it through the evaporator again. That darkens it up and makes for a stronger maple flavor. No additional time to produce syrup since we aren't adding any water back in. Not a controlled experiment but it seems to work for this dark syrup lover!

[GeneralStark]

First off...dark syrup is not necessarily inferior, it just has a slightly different flavor. If you say it's inferior, then you would be saying those that use red maples instead of sugars or wood fired evaporator instead of gas are making inferior product. It's just different.

These commercial producers don't "get it dark". Dark syrup comes naturally as the season progresses, and tends to outweigh the light. Producers will blend their light and medium syrups with some dark to make their preferred grade. A lot of them are not even producers, but bulk packagers that buy it by the barrel, blend to their specifications, bottle and re-sell.

I think there are a few reasons:
1. from a quality standpoint, it is easier for the producer to keep a uniform product from bottle to bottle and season to season.
2. how confusing would it be for the consumer to see variations of color in the bottles on the shelf(there can still be color variation within a specific grade), or see "more mapley" "less mapley" or "kinda mapley" on different labels. The producer would have to spend more on different labels and marketing to educate the consumer. The grocery stores would have to keep inventory of more products as opposed to just 1.
3. most consumers seem to have a predetermined idea of what maple syrup should look like (that perception being driven by the fake products like Aunt Jemima's), so grade A dark seems to outsell lighter grades in the grocery store.

This all makes sense if you market for wholesale to retail outlets. Now if you're selling from the shack or at farm markets, I say educate all the people you can. Let them decide what they like. You will probably end up with more repeat customers.

Dark syrup certainly is not inferior, and I find many customers prefer darker syrup. That said, light syrup is more "valuable" on the wholesale market so there is certainly an incentive to produce more light syrup if you will be selling your syrup bulk. This factor has certainly lead to the development of technologies that allow producers to process sap very quickly from tree to syrup, and produce very light syrup. Many have reported a trend in the industry towards more light "flavorless", "technosyrup" or "sucrosyrup".

The reality is that a producer has a great deal of control over the grades and quality of syrup they will produce in a given season. Saying that syrup just gets darker towards the end of the season suggests that it is out of a producer's control and maybe even some kind of mystical phenomenon that can't be controlled. Sure, you are more likely to produce lighter syrup early in the season and darker syrup towards the end, but there are some producers that only produce light syrup and some that only produce dark.

There are many tools a producer has available to produce the best quality product and meet the demands of their consumers. It is my belief that a producer's choice of equipment and how it is set up, their practices, and their goals are what determine the grade and quality of syrup they produce.

[michiganphil]

The reality is that a producer has a great deal of control over the grades and quality of syrup they will produce in a given season. Saying that syrup just gets darker towards the end of the season suggests that it is out of a producer's control and maybe even some kind of mystical phenomenon that can't be controlled. Sure, you are more likely to produce lighter syrup early in the season and darker syrup towards the end, but there are some producers that only produce light syrup and some that only produce dark.

There are many tools a producer has available to produce the best quality product and meet the demands of their consumers. It is my belief that a producer's choice of equipment and how it is set up, their practices, and their goals are what determine the grade and quality of syrup they produce.

Every bush is different, and every year is different(this year I made almost exclusively medium grade), but the trend is definitely that darker syrup comes later. Some people using bubblers in their pans are only making light syrup. Some people slowly simmering it on a flat pan over open fire only ever make grade B.

The most retarded thing about this whole grading dilemma, is that the color doesn't necessarily tell the flavor. Some people make "valuable" light syrup that may not have the "delicate maple flavor", it's just crappy. Some people make some wonderful dark syrup that is also not overpowering like the grade indications may suggest.

I agree 100% that you need to figure out your own goals, if you want to sell wholesale or retail, what your customers like, and what is feasible for your operation. The markets are very different, and each has its own specific demands. I say figure out what works for you, and don't worry so much about all the other stuff.

[Jeff E]

Every bush is different, and every year is different. This year all I made was light and medium amber. I think that is the case for most of the bigger producers in the area.
Last year, all I made was dark amber, B and commercial. It was warm and only with vac did I get sap for 6 days.
This year it was cold when all the big runs hit. Sap was always below 40 deg, and I had to process daily to keep up. Bacteria did not have much chance to get going.

It convinced me that the warmth (thus bacteria) was what is the biggest factor in my operation.

[markcasper]

Jeff, I agree with you about the bacteria being the biggest factor. Another thing is not to recirculate sap and concentrate and vice versa. That was a big no-no I had did in the past and now I still recirculate, but run it through only once and into its own tank and then from there run it again and right to the head tank. I hesitated this year of trying the new method, but after doing it the syrup got even lighter and this will become the new norm from here on out.

I had 80% LA, and of that , half was way lighter than LA. But we were blessed with good snow, little sun, some new pipe, new pans, a few new tanks, etc...and I think it all helped. The biggest of all was the cool conditions conducive to light syrup. I never had so much sap going through the RO with a temp of 2-3 C ever!

[wiam]

Jeff, I agree with you about the bacteria being the biggest factor. Another thing is not to recirculate sap and concentrate and vice versa. That was a big no-no I had did in the past and now I still recirculate, but run it through only once and into its own tank and then from there run it again and right to the head tank. I hesitated this year of trying the new method, but after doing it the syrup got even lighter and this will become the new norm from here on out.

I had 80% LA, and of that , half was way lighter than LA. But we were blessed with good snow, little sun, some new pipe, new pans, a few new tanks, etc...and I think it all helped. The biggest of all was the cool conditions conducive to light syrup. I never had so much sap going through the RO with a temp of 2-3 C ever!

I recirculated back into the same tank for the first time this year. I made more Fancy and Medium than ever and no commercial

[PARKER MAPLE]

I chatted with a fellow sugarmaker this season, he taps alot of soft maples and makes alot of dark syrup as well. Is this because there isnt as much sweet in a soft maple tree, compared to a sugar maple? I would believe that the less sugar been more boiling/cooking time in the pans wich would make a darker grade of syrup..

[markcasper]

I recirculated back into the same tank for the first time this year. I made more Fancy and Medium than ever and no commercial

I was just telling what I have did in the past and it ended up making a darker grade. The experts that I have listened to have said to run through once into a seperate tank at 50/50 (you get rid of the most water the fastest) and then run that week concentrate back through a second time to the head tank. I did this and was quite pleased.

It should be noted that at least where I live, we had ideal conditions for making light grades this year.