climate

Freeman’s Maple Research Podcast

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Just a quick reminder that the Ohio Maple Days registration is live – we hope to see you in December!

A couple months ago, I had the opportunity to sit down virtually with Aaron Wightman from Cornell and talk about the 3 year’s worth of data we collected to investigate Freeman’s maple production potential in comparison to sugar maples.  The research was conducted at OSU-Mansfield in the University research sugarbush, and Aaron did a great job leading the Sweet Talk Maple Podcast and keeping the conversation on track.  Please enjoy!  The episode can be downloaded and heard anywhere you get your podcasts.

Glad to See It Come, Glad to See It Go

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Thanks for Les’ contribution last Monday in his post – Is February the New March?  This is a more Mansfield-centric take on the 2024 season with a more in-depth analysis of statewide Growing Degree Days to compliment last week’s content.

What a season!  That sums it up in all the best and worst ways.  I stand by the words I typed in my 2/19 post – I believe we nailed our tapping date just about perfect.  The first run to follow was a marathon of 7 or 8 straight days, and the second run of the year culminated in our making syrup off the new OSU teaching evaporator for the first time ever.  Though many producers’ woods performed below average in terms of sap sugar, our Brix registered consistently at 2.0.  Talk about some highs.

We knew better.  The weather folks are not infallible, but there was no denying the forecast that lurked.  Warm, warm, and more warm.  But unexpectedly, February 21st was the death blow for our season.  While we were over at Malabar Farms helping out with an NRCS workshop on maple, our pump decided to quit working.  Without vacuum, the productive days of our season were over.  With a full season, we would likely have stayed tapped in until March 4th and posted one of our better season totals.  As it turned out in reality, the 2024 season ended on a low.

Looking more broadly around the state, the progression of Growing Degree Days (GDDs) was alarmingly early yet again.  If there any producers still resistant to the idea of tapping earlier than more traditional dates, then I don’t know what it will take to change minds.

Observe – Click Play for an animation of GDDs from 2021 (below).  Pay attention to 2 data points in particular.  First, the GDDs accumulated through March.  Second, the scale of GDDs on the legend.

Now, you don’t even need to see a similar video of 2024’s GDDs to know we covered lots more ground in fewer days than the previous year’s example.  Long story short, earlier AND hotter.  Hello sap season double whammy, goodbye sanitation!  I don’t believe many producers will be heard pining – “Boy! What I wouldn’t give for another season like 2024!”  And if you did hear such a remark today, then you probably also heard them quip – April Fool’s!!

Is February the New March?

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Remember when Les said he would come back at the season’s conclusion to tell you in 20/20 hindsight exactly what you may already suspect, he’s back to make some sense of the 2024 sugaring season!  Enjoy.

The Ohio maple syrup season ended on the first weekend in March.  This comes less than a week after President’s Day, the traditional starting date for the season in Ohio.  Of course, not this year as many Ohio producers started the 2024 season in January.  If you are a maple producer, you must wonder if the climatologist and everything we have been hearing about our climate is right.  Is February becoming the new March?  

Let’s analyze what we have seen and experienced in 2024.  OSU Climatologist Dr. Aaron Wilson has been telling us that the winters will get milder, and Spring will come earlier.  Once again, I refer to historical weather data to make a point using Weather Underground weather history maps.  Dating back to 2021, here is what I consider a relatively normal March (below).

Here is February of this year, 2024 (below).

It has been reported over the last several months that we ended 2023 with almost record-breaking high temperatures for November and December.  In fact, the climatological winter (December, January, and February) was the third warmest on record.  The 2nd warmest occurred in 1931.  The warm weather sent a warning to many maple producers, alerting them that something unusual was about to happen.  In Ohio, those that tapped in mid-January got it right.  Those tapping right after the first of the year were rewarded with 6 to 8 weeks of maple producing weather.  Many recorded over 14 boils before the first of March.  This year undoubtedly sets a new benchmark for early tapping.  Why did this happen and what can we learn from the experience.

The winter of 2023/24 followed the long-range forecast’s prediction.  With the exception of the invasion of a cold air mass in mid-January, the mild temperatures came back and continued throughout February.  This set up some extraordinarily good runs throughout the state.  However, a troubling and confounding factor was the overall lack of moisture.  I would say that many parts of Ohio were below average on moisture during this period.  Dryness in the woods is not good for maple production.  It is much preferred to have 4 to 8 inches of slowly melting snow, at the very least, lots of rainy days interspersed through the season.  I have seen woods that face north where the snowpack will last almost to the end of March.  These woods have produced good runs all the way to the end of March and even into April.  Not this year.

Here is the graph (above) showing the high, low, and average temperatures for the first two weeks in March.  The important thing to look at here is the minimum and maximum temperatures that clearly show we not only had daytime temperatures in the first two weeks March above 50 degrees F, but also had nighttime temperatures that approached and even hit 50 degrees.  This totally wiped out the freeze/thaw cycle, and we all know you cannot make syrup without a freeze/thaw cycle.  Sustained temperatures above freezing will undoubtedly be a recurring problem into the future.  Warm temperatures also accelerates the accumulation of Growing Degree Days, pushing the trees toward budding.  However, buddy sap did not end the season in much of Ohio.  It was the acceleration of microbial growth resulting from an abundance of unseasonably warm temperatures causing the sap to warm and foul systems.  It is almost impossible to make quality syrup under these conditions.  During the Ohio Maple Tour, I tasted multiple samples of syrup made in early March.  Just about all had that sharp taste of syrup made from sour sap.

Now comes the real challenge!  How do we prevent the possibility of this very marginal syrup from entering the market?  Especially in a year when many producers in states like Ohio had a poor year and now have syrup of questionable quality to sell.  Do you bottle the syrup and hope no one notices?  After all, it may have good color somewhere between Amber and Dark Robust.  The rationale in the past has been that most customers will not pick up on the off flavor; after all, they are used to high fructose corn syrup imitations.  The question now turns becomes, how much high-quality syrup will be made in the Northeast and in Canada this year?  Will the syrup they sell to the big box stores have better quality than what our customers can buy locally?  We already know it will most likely be less expensive.

In the end what have we learn? We added one more year to the string of abnormally warm maple seasons that we have experienced over the last 5 years.  For Ohio producers tapped in January, many experienced a near normal season.  Operations made some very good syrup that did not have quality issues.  Their markets are covered.  This also means that in 2025 when New Years Day rolls around, those producers who gambled right in 2024 will again be ready to tap trees at the first signal of good sugaring weather.  Unfortunately for many Ohio producers tapping later in the calendar, this year will be a hard lesson.  Those that tapped after mid-February found out that you cannot trust Mother Nature, because she does not read the Calendar.

A Little Science behind Maple Sugaring Weather

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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.

Anyone Tapping Yet?

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When to tap?  That is the question.  And when it comes to maple sugaring, that is THE question.  Currently, we are in the holding position at our Mansfield sugarbush and thankful for the cold temperatures that have descended on the region.  The longer the woods stay cold, the closer our trees will get to meeting their chilling requirement, and the more optimistic I will be when we do eventually start our season.  Put simply, if trees don’t sleep well, they can wake up cranky!

When we look to the south along the Ohio River, I see more good signs of zero accumulated growing degree days since the start of the year.  Note, this does not account for any warm spells we had around Christmas.

With that map in mind, a peek at online chat forums like the Maple Trader’s Ohio Forum reveals that several folks are already tapped in part or in full (January 2nd in Ross County, another early report out of Muskingum County).  Looking even further south to states like Kentucky and West Virginia, only early tappers were rewarded with last year’s ultra-warm and sporadic 2023 season.  That likely pushed some producers to move their tapping date earlier on the calendar.  Still, others are crossing their fingers that last year was an anomaly and going with a more traditional schedule again for 2024.

Taking the forecast up top at face value and speaking directly to our Mansfield site, there aren’t many (if any) quality freeze-thaw cycle days for a truly big run in the next 2 weeks.  If we do decide to tap in a week or so, we should at least get all our lines flushed and spot check the vacuum on the system while we wait for better conditions to kick things fully in gear.

Come back next week for a post from Les Ober where he discusses the question of tap timing and the effects of El Nino as we all wring our hands and stare into muddy crystal balls in search of the right answer to our question!

What Triggers Bud Break? Monthly Maple REVIEW

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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!

Mid (Late?) Season Update

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Chaos and unpredictability are apparently the new normal in the maple woods.  Fool me once, shame on me.  Fool me twice, well…you know the rest.  The past 2 sap seasons and current year’s production continues to highlight a new normal of early spikes in warm temperatures and the importance of being ready and willing to tap earlier than traditionally expected.  Producers wed to a historical norm will likely pay hefty cost this year.  Honestly, given the next few days of warm temperatures, we’re not sure our sap season will even make it to March 1st.

Our red x silver maples are starting to bloom and will likely be at or near full bloom by this weekend.  Though the buds on our sugar maples are still tight, the growing degree days (GDDs) are accumulating fast and tapholes are starting to dry up.  Hopefully those slowing tapholes are a combination effect of not just the warm temperatures but also the dry winter we have experienced.  I am not seeing much hope to erase the warm temperatures, but we are supposed to get drenched with a couple inches of rain tomorrow – that should help.

Here’s a photo I took this morning of the muddiest spot in our entire woods.  It is now bone dry and the used-to-be-mud is starting to crack and split.

The next week or two will tell the season’s tale – will we achieve an average season total, come up short again (maybe that’s the new normal?), or be surprised by a late spurt to make the year memorable in a positive way?  Only time will tell.

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

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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.

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

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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)

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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.