A Little Science behind Maple Sugaring Weather

Hands down, the number one question that comes up this time of year is “When should I tap?”

Due to the warmest December on record, I have heard a few Ohioans even asking “Should I have tapped in December?”.  When you look back over the years, the trend has been toward earlier tapping dates, but hoping that you can keep taps open for 3+ months is a bit of a stretch.  There is no way that will happen on a gravity system, and you will need more than a little luck even on high vacuum.

The scientific approach to planning involves studying climatological data and developing a plan based on that data. The maps below are long range weather predictions for the next three months. You can clearly see that all indications point to above normal temperatures for the next three months. For sugar makers what does this mean?

To quote a good friend and fellow maple researcher, “when you look at forecasts you need to look at it from the big producer / small producer perspective.”  Because most small producers tap everything at one time, they need to consider the value of a good short-term, 30-day forecast.  In most cases, especially if you are on a gravity system, you need to find the best 30-day window that will allow you to make the most syrup.  Once you tap, you are on the clock and that clock runs out shortly after 30 days.  On the other hand, if you are a large producer or even a medium producer on vacuum, you need to study yearly trends.  Trends will disclose what has happened over the last 3 to 5 years.  What we have seen is a trend to earlier tapping just about every year.  In most cases, early tapping has paid off in Ohio.  A major reason is that newer technology lends itself to pushing the envelope when it comes to tapping.  You have the advantage of running a semi-closed vacuum system utilizing 24/7 operation.  This lengthens your season considerably.

One of the most valuable pieces of data you can use are temperature history graphs for your location.  Weather Underground has some of the best.  They plot the maximum, minimum, and average temperatures.  Plotting the maximum and minimum will give you a good idea on the number of freeze-thaw days to anticipate for a month.  As we all know, freeze-thaw cycles are very important and drive daily sap runs.  You can look at these cycles over a five or even ten year period.  Over time you begin to see how various weather patterns play out.

Keeping in mind these are zip code specific but we are talking at the broad scale of an entire state, here are three February graphs. You can clearly see we started February leaving a warm end to January on two out of the three graphs.  In all the graphs, conditions continued to warm up as February wore on.  In two out of the three, the temps dropped going into March.  This may be a hint for what could happen this year.  2020 and 2022 were almost normal.  In both cases, our records show average to above average production.  2021 was the outlier and production was down for that year as temperatures stayed warm through most of March.  The other two years highlight the fact that starting out February warm does not mean you will march into March warm.

Too much science?  Here is a more common sense approach that prioritizes the size of your operation.  If you are tapping thousands of taps, you must start early to get the job done.  For a moment, think about a huge 50,000-tap operation.  Should they consider tapping right after the first of the year?  Definitely!  One of their strategies is to tap 5,000 taps super early.  This results in the Facebook posts you may have seen bragging about syrup being made over Christmas.  Several big producers in the East did this in December.  Does that mean they tapped everything?  Most likely not.  A large commercial producer hedges their season by tapping some early and the rest over the month of January with everything in the tree and ready by February 1.  Small producers who are setup to boil early can also do this, the only difference is they may start tapping their early running trees shortly after New Year’s but plan to finish out in February.  This keeps fresh taps in the system and prevents you from putting all your eggs in one basket.  The best way to accomplish this is to keep very good records.

That brings us back to our initial question.  When should I tap this year?  All indications are that we are going to have a warmer than normal winter.  If you are in Southern Ohio, you might be tapped already.  North of I-70, you should probably hold back until the end of January.  This is where analyzing the 30-day forecast is critical.  Studying several long-range forecasts a little closer, I noticed that we may have some of the coldest weather of the winter on the last week of January and the first week of February.  While the forecast is showing a warming trend coming off several weeks of genuine cold weather, depending on your situation you may even want to hold off until the first week of February.

Of course, the joker in the deck is the El Nino weather event we are experiencing.  El Nino’s are known for extremes and all it takes is a bend in the jet stream and you could be looking at 10 more days of below average weather.  Once this happens, you usually go right back to the warmer than normal pattern.  In this case, cold weather is your friend.  What we do not want is 10 days straight above normal!

As for my prediction!  I will tell you what kind of season we had in 2024 on the first week in April.  May your sugar season be long and sweet.

Change Over a Century: Monthly Maple REVIEW

Here is May’s edition of our feature Monthly Maple Review.  Once a month, we review a research article to spotlight key findings, investigate curiosities, and uncover important implications for Ohio’s maple producers.  Please comment below if you have thoughts, ideas, insights, or questions.  If you stumble on to a new maple article and want to see it highlighted in a Monthly Maple Review, please reach out to me via email – karns.36@osu.edu.

Phenology, put simply, is the study of nature’s timing.  A couple years back, we did a special article series on the use of growing degree days (GDDs) to monitor and predict the progression of trees and shrubs in Ohio.  Typically, sugarmakers are most keyed in and interested in whether maple trees are early, right on time, or late to produce the sap runs we convert into maple syrup.  But phenology gets at much more than just the time of year we make syrup.  Leaf out, dormancy, seed development, emergence of different insect pests, fall color change, and leaf drop are all elements of the annual cycle of plant phenology.  Phenology is a topic we keep coming back to you, but it’s interesting, it’s important, and it’s complicated – so we are back again!

This month’s article, published in March of this very year, is titled “A Century of Climate Warming Results in Growing Season Extension: Delayed Autumn Leaf Phenology in North Central North America.”  Authors Kellen Calinger and Peter Curtis (both Ohio State University researchers in the Department of Evolution, Ecology, and Organismal Biology) published their study in an open-access journal called PLoS ONE.  Open-access meaning, if you want to read the full paper, you can access the article here.

The methodological approach for this research paper is particularly interesting and clever.  A farmer named Thomas Mikesell from Fulton County, OH, collected data from the years of 1883-1912, meticulously recording phenological and meteorological information that was preserved in a massive 700+ page publication that is still accessible today.  Kellen and Peter, the modern day researchers from Ohio State, used Mikesell’s observations as a baseline to compare data from 2010-2014, a full century later.

Among the tree species selected in their study (they chose 7 in all), no Acer maple species were chosen unfortunately.  However, the beauty in this study’s approach is the real focus on this month’s review.  It is both elegant and simple to think that someone’s observations over 100 years ago could serve as such a significant monument in time to understand how conditions shift and change through the decades, even centuries.  Sometimes science gets complicated, complex, to the point of absurdity it seems.  This is a pleasant reminder that there is profundity in the simple as well.  Write down your observations, allow time to pass, make more observations, and compare.  Simple.  Done.

I believe there is a lesson here for us all – take notes, jot down curiosities, record all the important dates from every sugaring season.  And most importantly – save those scribbles and notes in a place where not only you, but the next generation too, can find them and propel your own personal learning journey.  Just in case you don’t recognize the common name “white maple” – that’s silver maple.

If you’re from northwest Ohio, or even just from the upper quarter latitude of Ohio, I strongly suggest you peek at this table to see how your observations jive (or don’t jive!) with Mikesell’s observations back in the late 1800s.   What conclusions do you draw?  Are there big differences for each observational category – first fully formed leaf, in full leaf, in blossom, fruit ripe, and complete change of foliage?  Or are some categories different, but some phenomenon right on schedule and unchanged?  It is important to remember that phenology is driven by a host of factors (as we noted in our March Monthly Maple REVIEW) – shifting climate is one factor, but precipitation plays a role, active and recent weather events/trends, photoperiod (fancy name for day length), and more.  Observations that have not changed much on the calendar are likely responding to more static and unchanging factors such as photoperiod.  Observations that do differ, those are more likely triggered changing climate and other more dynamic factors.

If you’re not from that part of Ohio, dig up those old records that your dad’s dad kept back when he ran the sugarshack in years bygone.  Rifle through the old drawers of dusty old spiral-bound notebooks.  Flip over the back of black-and-white photographs to see if there is an inscription that reads “first boil, 1952.”  All those memories are also records, and we learn about the present when we look to the past.  So I guess this review is less of a review and more of an admonishment – bear witness to the power of data collection and long-term record keeping.  Participate in keeping notes.  If nothing else, those notes will be curiosities to be pondered years down the road.  At best, meticulous notes and records can help you make sense of the dynamic, cluttered, and information-dense world that we live!

 

What Triggers Bud Break? Monthly Maple REVIEW

A brief introduction to this new feature – Monthly Maple Review – we review a research article once each month to spotlight key findings, investigate curiosities, and uncover important implications for Ohio’s maple producers.  Please comment below if you have thoughts, ideas, insights, or questions.  And if you stumble on to a new maple article and want to see it highlighted in a Monthly Maple Review, please reach out to me via email – karns.36@osu.edu.

Bud Break in Sugar Maple Submitted to Changing Conditions Simulating a Northward Migration” by Ping Ren and colleagues.  This article was published in 2021 in the journal Canadian Journal of Forest Research.

In our first Monthly Maple Review, we looked at producer attitudes and behaviors regarding climate change and its projected impact on maple.  For this our second installment, we focus on how a simulation experiment predicts climate change will effect bud break in sugar maples.

As climate shifts and range-restricting thresholds follow, plants and animals must adapt and keep up with changes or risk being left behind.  Many organisms are well-suited, at least from a mobility standpoint, for keeping up – take birds and their gift of flight for instance.  Other species likely face serious challenges; the American pika is commonly pointed to as an example.  Pika are small, marmot- or groundhog-like creatures that live in treeless alpine habitat in the Rocky Mountains.  It is easy to imagine pika being literally stranded on mountain peaks above timberline unable to migrate and keep up with shifts in suitable range.  Many plants are also considered less adaptive to shifting conditions and may not be able to move into higher latitudes or elevations necessary to keep up with suitable growing conditions; sugar maples are no exception.

In emergency scenarios, assisted migration is a solution whereby humans literally help other organisms keep up with shifting climate conditions.  Already, experiments have been conducted with many plant species, including some trees such as the whitebark pine, to verify suitability of growing conditions beyond the current limits of the species distribution.  Will sugar maple or other maple species need a special assist from us?  No one knows for sure, but studying what factors drive bud break is a small step to understanding if they are likely to need our help in the future.

The essence of Ping Ren and team’s experiment was to examine bud break under controlled conditions while varying temperature and photoperiod (also known as day length).  The experiment’s most basic hypothesis was that “photoperiod outweights temperature in initiating bud break when the chilling requirement in unfulfilled.”

To understand the study’s results, we first need to wrap our minds around 3 main environmental factors, or signals – the variables we believe most plants are responding to when they wake from winter dormancy and start to stir towards bud break.  First, winter chilling – more intense and longer periods of cold during the heart of winter contribute to chilling.  This deep freeze is what resets the annual clock of trees and influences the trigger of growth reactivation.  Perhaps it is worthwhile to think of chilling as similar to a human experiencing a prolonged session of deep sleep.  Second, spring temperature – this is just what it sounds like.  In a simple system, cooler spring temperatures may wake plants from deep sleep more slowly than a rapidly warming and sudden onset of spring (check out a series we did in winter 2022 on growing degree days to better under the role of spring temperature).  And finally, photoperiod – more commonly known as day length.  The most important thing to note on this final factor is that while any given year might vary in terms of winter chilling or spring temperature, length of day is fixed and will always be fixed regardless of where climate change takes us.

While each factor in isolation is relatively easy to understand, it is the complicated interactions between winter chilling, spring temperature, and photoperiod that likely determine the actual timing of bud break in a species.  This study ran 2 experiments that essentially confirmed the hypothesis that sugar maple bud break is more determined by photoperiod than by spring temperature when the requirement for chilling is not met.  Let’s put that another way – during winters that do not put sugar maples into a deep sleep for long enough (winter chilling), day length has more of an effect on bud break timing than how cool or warm spring temperatures are.  In other words, the experiments confirmed the authors’ central hypothesis.

Let’s unpack that a bit more and talk about some take home messages.

Resetting a sugar maple’s internal clock is accomplished primarily by meeting the chilling requirement – being cold enough for long enough.  When that chilling requirement is not met, it takes additional and louder signals to wake up a tree from dormancy to initiate bud break.  While this might sound a bit counterintuitive, the fact is that waking up a tree from a deep sleep is easier and more predictable than trying to wake up a tree that has been tossing and turning in its winter bed.  Under changing climatic conditions, warmer winters may result in unmet chilling requirements that ultimately result in delayed bud break thereby shortening growing seasons.  But remember, winter chilling is just the first consideration.  What about spring temperatures?

At face value, most sugarmakers understand the effect of a warm spring – trees break bud faster.  In a cool spring, buds stay closed longer and the sap season might last a bit longer too.  In a worst case scenario, climate change wreaks complete havoc on winter weather not allowing sugar maples to adequately chill and temperatures jump back to springtime highs so quickly that any sap season is effectively crowded right off the calendar.  That’s where day length seems to play a crucial and important role.

Think of day length/photoperiod as a speed governor on a go-cart.  I hate so-called governors growing up.  I wanted to ride my go-cart at top and dangerous speeds, but my parents set the speed governor so that I could only drive certain speed limits.  When spring temperatures warm abruptly and it seems that the sugar maples might break bud extraordinarily early, length of day pumps the brakes and slows down that process regulating it closer to normal.  Essentially, photoperiod may be a crucial regulating factor to keep sugar maple bud phenology more on track than would be expected otherwise.  In the authors’ own words – “Because day length will not change under climate warming, photoperiod becomes ultimately limiting when bud break in sugar maple occurs too early.”

So where does that leave us?  Will sugar maple need our help in assisted migration as conditions change faster and faster into this and coming centuries?  Time will tell, but if this study teaches you nothing else – you can certainly walk away with 2 big takeaways.  First, trees are remarkably complex organisms.  And second, trees have a few tricks up their sleeves!

Another Topsy Turvy 2023 Maple Season

Our 2023 maple season was yet another sub-par year subjected to early and frequent warm spells.  2023 marks the 3rd consecutive year that our first run of the season ended not because temperatures took a prolonged dive below freezing but because temperatures spiked into the upper 50’s or low 60’s.  Three years in a row!  Crappie fishing weather to end the first run of the season!  Starting off a season with a warm temperature spike sets the table for sanitation issues, and those challenges were forefront to yet another Ohio maple season.  For all practical purposes, our production season at the Ohio State Maple woods was over by March 1st.

Early tappers were rewarded this year making the most out of a tough season.  A few producers up north are holding out for a final run or two before also switching to post-season tear down and cleaning duties.  How the entire state fares is yet to be determined, but the individual producers I have spoken with are not ecstatic over the year’s production totals.  The bottom line is that Ohio appears poised to enter, heck we might already be in, a new normal.  Though spring is temporarily stalled with the current slight cool down, spring invaded winter like a unexpected marauding army.  To get an idea of just how early 2023’s spring has been, check out the time-lapse map from the National Phenology Network.

Regardless of whether you are a producer up north with a few more days of boiling on your horizon or if the season is a memory at this point, be sure to check out Future Generations University’s webinar next Thursday evening.  On March 16th at 7 PM, the Out of the Woods semianr series will focus on post-season sanitation.  Mike Rechlin and Kate Fotos are going to share best practice guidelines on keeping your sugarhouse and your sugarbush spic and span headed into the off-season.  You can watch the webinar on Youtube or get your own registration link through Zoom here.

Climate Change & Maple: Who Cares?! Monthly Maple REVIEW

A brief introduction to this new feature – Monthly Maple Review – we review a research article once each month to spotlight key findings, investigate curiosities, and uncover important implications for Ohio’s maple producers.  Please comment below if you have thoughts, ideas, insights, or questions.  And if you stumble on to a new maple article and want to see it highlighted in a Monthly Maple Review, please reach out to me via email – karns.36@osu.edu.

A Changing Climate in the Maple Syrup Industry: Variation in Canadian and U.S.A. Producers’ Climate Risk Perceptions and Willingness to Adapt Across Scales of Production” by Anna Caughron and colleagues.  This article was published in 2021 in the journal Small-scale Forestry.

The maple syrup industry is on an undeniable collision course with changing climatic regimes – shifting tree composition, more unpredictable and earlier sap seasons, and potential reductions in yield are all staring back when we look into the future.  This list represents just the tip of the looming iceberg, and more southerly producers anticipate an even rockier path forward as evidenced by some impacts that we can already talk about in the present tense.

Anna and her co-authors are not the first team to survey climate-related issues amongst producers, and perhaps we will review other similar papers down the road.  But one interesting angle, beyond the normal suite of factors like age or education or political affiliation, that this study examined was producer scale.  Does producer scale impact willingness and ability to adopt climate-adaptation practices in maple production?  Let’s first clarify what a climate-adaptation practice is.  Consider the effects of shifting tree composition in Ohio.  That shift will likely lead to increased dominance by red maples.  Adapting to that effect would be to tap a diversity of maple species, not just sugar maples.  Failing to adapt to shifting tree composition could lead to reduced tap quantity because of unwillingness to tap anything except a sugar maple.

With that point clarified, two over-arching findings stuck out to me.  First, nearly 90% of all surveyed producers agreed that maple syrup production is closely linked to climate, and only 15% of small producers (<2,000 taps) believed climate-induced impacts would be a net positive to their operation.  How often does that lop-sided a percentage of folks agree on something?  Not often.  Second, larger producers are more willing to adopt more climate-smart adaptation practices than medium or small producers.  And guess what, political affiliation had nothing to do with any of the above.  Yes, you read that correct – climate and maple is apolitical.

Before we dive into the specifics, know that it took 10,000+ taps to be categorized as a large-scale producer in this study.  Quite frankly, most US producers in this study were small or medium, and most Ohio producers would certainly be “small.”  A final caveat, before we dive into a few specifics, is that among the 354 survey respondents in the study, only 12 hailed from the Buckeye State.

Canadian producers, which are also more likely to be the “large” producers, are more apt to fertilize their sugarbushes and practice intensive silviculture, but significantly less likely to increase the number of trees they are tapping.  I can see the practice of fertilization.  Personally, I believe all maple producers – regardless of scale, should practice active silviculture in their maple woods.  The goal of active silviculture after all should be healthy maples!  The last point about tap quantity is a hard one to understand…until you discover that rules enforced by the Federation of Quebec Maple Syrup Producers prohibits most producers from increasing their tap count.  Given that most large producers are also Canadian, the pattern of stubbornly maintaining tap count then makes some sense.  I certainly learned something new with that fact pointed out to me.

“Medium” producers were more likely to tap earlier, implement rigorous sanitation practices, and stay up to date on latest research finding than “small” producers.  Multiple factors could be play as “large” and “medium” producers increasingly differentiate from “small” producers.  I’ll quickly highlight just one factor as I grapple with the study’s findings.  Some “small” producers are undoubtedly hobby producers.  Making syrup is fun and as soon as it seems like work, well…where’s the fun?  I can easily see why an individual producer with 100 or 2 taps would decide not to invest in high vacuum efficiencies.

Putting aside scale of producer and applying the lens of producer age, we learn that tapping red maples and using high vacuum systems are less likely among older producers.  Only focusing on the practice of tapping red maples, this fits within the pattern of a traditional no-no generationally passed down.  Not until more recently has University research been dedicated to documenting production potential in alternative maple species.  What’s that saying about “old dogs?”

I’ll wrap this review up by pointing a finger back at myself – a maple educators.  This sentence from the study speaks for itself, “Only 20.9% of producers…thought that information on climate change impacts on the maple industry was easy to access.”  Yikes, that is a huge wake-up call and harsh criticism for the University community.  Hopefully this site can help address these knowledge gaps for Ohio maple producers, and this Monthly Maple Review series is part of the solution.

Borers, Feeders, and Galls Oh My!

Ohio Maple Days 2022 did not disappoint.  The food was fantastic, the vendor room crowded, and the presenters shared a wealth of knowledge of expertise across a wide range of subjects. Dr. Curtis Young, Entomologist, Extension Educator, and Associate Professor, expanded our knowledge regarding maple pests.  Many that most of us were already aware of, spotted lanternfly or Asian long-horned beetle for instance, and lots of lesser known pests.  Before we get into a few highlights, be sure to mark your calendars for next year’s conference December 8th and 9th!

Any attempt to summarize Dr. Young’s talk would fail due to the sheer amount of information that he is able to share in such a short amount of time.  And no notes!  Truly a wealth of knowledge.  Rather than attempt a synopsis, this is a great opportunity to share some general resources and up-to-date information for some of the more alarming maple pests we face here in Ohio.

University of Kentucky Extension has a great webpage that quickly catalogs a wide range of known pests across 4 general categories – leaf feeders, sap feeders, borers, and galls.  While most maple pests are just that – pests, similar to how most of us view the average mosquito, a few present a real and present danger.  That said, if your maple trees are stressed already, a relatively harmless pest can be the proverbial straw that breaks a camel’s back.  Moral of that last sentence, practice healthy silviculture and sugarbush management to ensure your trees are healthy and vigorous.

Asian long-horned beetle are always mentioned in these presentations.  Thankfully, in Ohio at least, control and eradication of Asian long-horned beetle is a success story that we seldom get to herald in the fight against invasive species.  While we keep our eyes out for future infestations, spotted lanternfly has rapidly expanded its range and our state records now show several counties with positive detections.

An excellent website to stay abreast of issues facing plant, shrub, and tree health is Buckeye Yard & Garden onLine where Dr. Curtis Young and many other experts from Ohio State University Extension provide “timely information about Ohio growing conditions, pest, disease, and cultural problems.”

Upcoming Webinars – Weather & Worms

Two webinars are coming quickly on the calendar.  And yes, you read the post’s title correctly…

First, a perennial favorite speaker is coming to Future Generations University “Out of the Woods” seminar series next Thursday, January 19th.  None other than Aaron Wilson from Ohio State’s Byrd Polar and Climate Research Center will be discussing the weather and how it impacts your sugarbush.  If this talk is anything like usual, he delivers excellent information about general effects and then dials it in to the prognostications that seem to be developing for the current and upcoming sap season.  Click here to register – next Thursday night at 7 PM. 

And second – Wednesday, January 25th at 3:00 PM, Penn State Extension will be offering a webinar called “Stressors of Maple: Dieback and Mortality.”  The webinar will be recorded and sent to everyone that is registered.  The webinar will host speakers from Michigan Technological University and will cover what maple decline is, what is driving maple decline, how earthworms impact maples and native forests, and how to respond if you have maple decline.  For more information and to register for this January 25th webinar, click here.

Upcoming Maple Events

There is a flurry of upcoming maple programming and events to consider.

Of course, the International Maple Conference just concluded up in Lacrosse, Wisconsin held over the latter part of last week and weekend.

Next weekend, the Ohio Maple Producers Association are convening for a great line-up of food, fellowship, tours, and syrup contests.  Dates are Nov 4-5 and additional details can be found here.

Just a few days after, Seldom Seen Farm will host a Woodland Wednesday program from 4:00-7:00 PM on November 9th.  In collaboration with Geauga Soil and Water Conservation District, Geauga County Farm Bureau, NRCS, and host Seldom Seen Farm, speakers will discuss the relationship between modern forestry and the maple industry.  Specific topics will include thinning, tree crown development, soil conditions, and maple tubing in the sugarbush.  All are welcome to this free outdoor event that will benefit the landowner and woodsman alike.  Please RSVP to Kevin Holy at 440-596-9717 or via email (kevin@seldomseenmaple.com).

Lake Erie Maple Expo, the following weekend of November 11 and 12, will host its usual showcase of vendors, talks, and all and everything else maple.

Completing the first half of November flurry, Penn State Extension Educator Brian Walsh will discuss what is known about the spotted lanternfly and observations about maple trees that provide insight as to the impact the insect could have on the industry.  Pennsylvania has endured a longer stint of spotted lanternfly infestation than Ohio, and we can learn more about what to potentially expect by seeing what has been learned by our neighbors to the east.  Register for the November 16 – 10:00 AM webinar here.

How to Combat Buddy & Sour Sap – The Path to QUALITY Syrup (Part 4)

Prevention of sour sap is all about sanitation. Here are a few things to consider when developing a sanitation plan for your maple operation. As soon as the previous season ends, producers using tubing need to clean and sanitize their lines. There are many ways to do this, but the most important thing is to make sure it gets done. As the new season approaches, inspect your lines for sanitation problems, consider replacing not only the spouts but the drops and tees if needed. As the new season begins, producers using high vacuum should consider running your vacuum 24/7 to keep your lines clean, clear, and cool.  During the season, make sure you wash your holding tanks often to prevent microbial scum buildup.

Where sap is held for a long period of time, avoid using plastic tanks for long term sap storage. Plastic is porous and retains bacterial inoculum that will quickly generate bacterial growth. These plastic tanks are often referred to as commercializers, named after the old commercial grade of syrup that nobody wanted. Once a plastic tank becomes contaminated, they are almost impossible to clean and should be replaced.

In the sugarhouse, making quality maple syrup starts with your reverse osmosis (RO) unit. Concentrate must be evaporated as soon as it comes off the RO. Bacteria multiply quickly in concentrated sap. This is the result of a higher percentage of sugar in the concentrate. There is also an increase in the sap temperature as it moves through the RO. It may enter the RO at 40 degrees F or less, but when it comes out, it will be closer to 50 degrees F. High Brix concentrate, elevated sap temperatures, and a warm sugarhouse are the perfect recipe for taking good sap and turning it into a microbial cesspool if not careful. This is one of the reasons many producers are now considering using refrigerated milk bulk tanks to store concentrate. This cools the concentrate and allows more time to manage the boiling process.

Producers often accept the fact that concentrate left on the evaporator overnight will produce a darker grade syrup, at least until fresh sap is introduced.  This does not have to happen if managed properly.  Small evaporators should be drained if possible. Larger evaporators can be equipped with a wash system that allow the entire evaporator to be cleaned and drained. Once the syrup leaves the evaporator, the process of sanitation continues. Syrup should be filtered and placed in a stainless-steel drum after being reheated to at least 180 degrees F. There is an inherent risk when you attempt to drum syrup at lower temperatures. Spoilage happens when barrels are packed at low temperatures. The hot syrup and cold barrel causes condensation (H2O) which combines with the remaining air in the barrel ultimately resulting in mold and fermentation.  It is best practice to place filled barrels in a cool place like a basement or a barn that does not heat up. Another practice worth looking into, is to build a cool room by equipping  a small insulated room with an air conditioner.

When you re-open a barrel of syrup, you should have syrup that is ready to bottle. When you bottle your syrup bring the syrup back up to 185 degrees for packing. Syrup packed below 185 F is subject to spoilage and reduced shelf life. Going above 190 also creates several problems. And if the syrup peaks above 200 F, the syrup will start to foam, and niter will start precipitate. The only solution for this scenario is to filter the syrup again. You will also overheat your jugs causing them to contract and suck in if they are not 100% filled. Plastic jugs should always be filled within a half inch of the top and laid on their side to kill any bacterial that may have found its way in the jug.  If you pack in glass bottles, make sure you put your bottles in the oven at 200 degrees for a few minutes. Hot glass will not condensate moisture and you can eliminate most problems with this simple step. It is always good to pack several times over the course of the year to maintain the highest quality in your syrup.

Many years ago, there was a use for commercial outlet for sub-standard syrup. The majority was sold to the tobacco industry. It was used to sweeten chewing tobacco. That outlet for the most part no longer exists. There are places where substandard syrup could be used but its objectionable flavor drastically lowers its value. For this reason, there is now a movement to prevent this type of syrup from getting into the market. Bulk buyers no longer want to handle sub-standard syrup and if they buy it they are not going to pay very much for the product. In addition, there is a currently an effort by the International Maple Syrup Institute and others to promote educational programing to raise producer awareness about ways to avoid producing this kind of syrup. The reality is that there is very little economic return from sub-standard syrup production. With rising costs of equipment and inputs the production of anything less than top quality saleable syrup in today’s high demand market is foolish.

There you have it – a 4-part series starting with a lesson on phenology and how to track growing degree days, relating growing degree days to tree bud development, appreciating the differences between buddy sap and sour sap, taking sanitation seriously at every single phase, and PRESTO! viola! alakazam (if only it were that easy!!) – you are making QUALITY maple syrup!

Off-Tasting Syrup: Understanding the Culprits (Part 3)

Now that we have talked about tree phenology and maple buds and growing degree days, let’s the talk more about the main prize of every sugarmaker’s dream – QUALITY syrup!  As we get ready to embark on a new maple season, let’s go over some of the things that will help you to improve the quality of your syrup in 2022. We all know that paying attention to detail in the woods will pay off with big rewards; however, the place where paying attention to detail is most important is when the sap or concentrate is on the evaporator. The finishing process can make or break your operation. Maple production is becoming a very competitive business, and the producers making the highest quality syrup will rise to the top.

Here is an oversimplification of what happens during the syrup-making process.  Once bacteria are introduced into the sap, a conversion of sugars takes place. A portion of the maple sap, which is almost 100 percent sucrose, is converted into glucose and fructose. This portion of the sugar content makes up the invert sugars present in syrup. When the sap is heated (The Maillard Reaction – something you can read more about here) the color of the syrup and the flavor of the syrup is formed, largely based on the amount of glucose and fructose sugars and other factors happening at the same time.  Thus, the level of microbial interaction plays a vital role in determining the color, grade, and corresponding flavor profile of the syrup produced. So, as you can see not all microbes are bad, in fact they are essential to everything we love about maple syrup!

Sap flowing from the maple tree is sterile, so where do the microbes come from?

Microbial activity begins as soon as sap is exposed to the outside environment. Early in the season microbial development is slow due to the normally cold temperatures, but once warm weather arrives (above 50 degrees F), more and other strains of microbes begin to multiply in the sap. As the microbes interact with the sap, the syrup produced darkens and develops an increasingly bold and pronounced maple flavor. Microbe colonies continue to expand eventually resulting in very dark and viscous syrup with an unpalatable strong flavor. Because this degradation of the sap is more likely to occur at the end of the season, low quality syrup is often associated with tree budding which happens at approximately the same time.

If you did a taste comparison, you would notice is a definite difference between buddy syrup and sour sap syrup. Buddy syrup has a chocolate flavor akin to what a Tootsie Roll tastes like while sour sap syrup has a bitter sometimes fermented taste that stays in your mouth. If you boil buddy sap, it will produce a pungent unforgettable smell. Sour Sap thickens to the point where it cannot be evaporated and will be difficult to draw off the evaporator. In extreme cases, you can pour a stream out and it will suspend in midair. This is referred to as “ropey syrup”. Sour sap is a result of intense microbial activity that builds anytime during the season when environmental conditions are right for bacterial growth. Buddy syrup comes from sap collected when the buds emerge naturally from the tree. This is a normal physiological growth stage that occurs every year.

Both processes require and progress with seasonal warming. In a normal season, the two tend to occur simultaneously and accelerate at the end of the season. Though the two are correlated, it is important for producers to understand the differences if you want to avoid the problems associated with each.