Join our own Les Ober and Mike Rechlin to learn about maple syrup quality standards along with the ins and outs of syrup grading Thursday evening 7 PM on April 15th. Register HERE!
Watch this time lapse video of maple research taking place at the Ohio State Sugarbush located on the OSU Mansfield Campus.
Across 13 racks with 5, 6, or 7 canisters each, the OSU maple team emptied sap to monitor individual tree yield and sap sugar content…daily! The 75 research canisters will help us answer questions about how red x silver hybrid trees (Acer freemanii or “rilver” for short) compare to sugar maple production standards. The PVC canisters are a new design engineered by the team, and vacuum consistently achieved levels in the 22-25 pounds range. A drill pump mounted on a standard cordless drill boosted our sampling efficiency, and a digital Misco refractometer handled sugar readings.
While the data won’t be formally analyzed for a bit, we were surprised just how variable individual trees performed based on sap volume as well as sap sweetness. A couple trees achieved sugar content readings over 3 even at the end of the season. While other trees struggled to break 1.2 or 1.3% all season. For yield, 2-3 gallons a day was average for some trees. Normal for others amounted to just 1 or 2 quarts. The team is pulling down the research equipment now for off-season storage.
Stay tuned for updates.
Just like snowflakes no two maple seasons are exactly alike. No question about it, this season fooled me. After about 5 years of early tapping, along comes 2021. During December and January, we experienced above normal temperatures leading to what many believed would be one more in a string of early tapping seasons. Tapping in January has become almost routine across Ohio. However, just like a deck of playing cards, every deck has 2 jokers. This winter season we had two meteorological jokers.
The first was the presence of a strong La Nina with its trademark warmer and wetter weather conditions. Hidden in the background far to the North was the second joker – the always volatile and never popular polar vortex. A polar vortex is always a possibility during the winter months. You never know when the jet streams will line up just right and push Artic air southward into our region. This year we did not experience the full brunt of the vortex like we did in 2014. The coldest air stayed well to the west of Ohio. However, we did experience a cold spell that dominated 20+ days of February.
As result of the persistent polar vortex, the start of the 2021 maple season was pushed back until the last week of February and first couple days of March. Even southern Ohio producers were forced to tap two to three weeks later than normal. The first of March is not historically an abnormally late starting time for maple season in Ohio. The one dominant factor that makes this season different is that our weather is still being somewhat controlled by a strong La Nina weather pattern. The threat of an early warm-up and above normal temperatures are real. And the first indication of that was the stretch of 60-70 degree temperatures experienced during the middle of the second week of March. This was enough to trigger budding in red maples and silver maples of southern Ohio.
At the same time, many sugar camps in northeast Ohio set one day records for syrup production. Sap flows were exceptional after the long cold spell of February. As of March 12th, the same camps are reporting a half crop entering the third week of March. The above normal temperatures experienced at the end of the second week, pushed the season close to the brink. Conditions also caused a dramatic change in syrup grade, and Dark Robust and even Dark Strong profiles have mostly displaced the Golden grade of early season.
The next two weeks will determine the outcome of the maple season in Ohio. OSU Climatologist Aaron Wilson is predicting a mixed bag of weather conditions for the rest of the month. There will be some below freezing temperatures but nothing extreme. For southern Ohio, the trend is for slightly above normal and for northern Ohio – normal temperatures. Again, we may or may not see those colder low temperatures needed to reset the trees and delay budding. What is also troubling is the lack of moisture. 2021’s recent precipitation trend is not typical for a La Nina year, and drier than normal conditions are slowly creeping into Ohio. We need precipitation, snow preferred, to keep the sap flowing, but that key factor is largely missing in the forecast for northern Ohio. At this stage, we need a hybrid of the two jokers to keep this season productive.
I will keep my prediction for the rest of March to myself, goodness knows the first two months of 2021 fooled me. That said, I will be able to confidently predict the outcome the 2021 maple season in Ohio on the 15th of April. What is it they say about hindsight?
Personal point of pride to share this photo of my 9 year old daughter Raelyn holding her first ever recorded datasheet. She persevered for 4 hours of research last Sunday afternoon and evening to help me empty 75 sap chambers during a small sap run. It has been a true team effort to pull off the ACER research project! It seems uncertain right now just long the 2021 season will or will not last, but regardless, the 3 years of this project will allow us to answer some interesting and important questions for Ohio maple.
Despite being virtual due to COVID-19, 2021 Ohio Maple Days – or more accurately Ohio Maple Day sans the “s” – was a success. The audience, two hundred or so strong, heard presentations on tapping and updates from our ACER grants in addition to how production might be increased with red maple. A big thanks to this year’s speakers and an extra round of applause for the committee who worked hard on an event that looked quite a bit different than in years past. One silver lining to having a virtual event is that the sessions are easily recorded.
Visit the Ohio Woodland Stewards Maple page and scroll to the bottom of that webpage to access the different presentations. Let us know what you think and send us any questions, comments, concerns, or suggestions to talk topics for next year!
Join OSU’s Les Ober, Geauga Co. Extension, and SENR’s Gabe Karns and Kathy Smith, for this session on how to make your own syrup or explore turning your woods into a sugarbush as an income opportunity. We will talk some history, tree species to tap, how to tap and how to boil and bottle maple sap. Have a few trees in the yard or a woods that has potential? We will try to answer all your questions.
Old Man Winter finally loosened its grip and maple sap is flowing! For comparison using growing degree days (GDD) on February 28th, we were at 16 GDDs and 22 GDDs in 2019 and 2020 at our sugarbush on the Ohio State Mansfield campus. 2021 GDDs will likely tick up for the very first time on this – the final day of February; however, the extended forecast looks iffy whether we will get many of the needed recharge cycles with nighttime temperatures in the high 20s or lower. Whatever the season may bring, our research is progressing nicely and the first data of the 3-year project is being collected.
Students have worked hard to get PVC research canisters built to collect sap off individual maple trees. COVID-19 reared its ugly head by disrupting the shipping supply chain and a University-wide switch to a new fiscal operating system caused further delays for all the components to arrive. Though we had working prototypes built by early January, we used up every bit of time that Old Man Winter’s stranglehold gave us to finish the entire research system. What a relief when the final pallet arrived, the last canister was assembled, and pressure testing confirmed our DIY canisters were a success!
With warmer temperatures on the forecast and piles of snow melting away, last week was an all-out scramble to get our upgraded vacuum pump cranking, production taps running (a smidge over 1,100 for the 2021 season), single tree canisters situated in their collection racks, research trees hooked into the research system, and an additional fleet of buckets/lids installed across campus in the crop tree release demonstration area.
Student help has been and will continue to be integral to our success. And Anthony Tambini – a recent graduate from the School of Environment and Natural Resources – has been full-time on the project since January 1. Without the students and his help, none of this would be possible.
Moving forward, daily sap measurements (volume and sugar content) will be taken from each individual research tree’s canister through the end of the season. Buckets will be emptied daily in the crop tree management zone as well. 2021’s data will be the first of 3 years to examine potential differences between maple species and between crop tree treatment groups (much more on that in a later post!).
We all wonder what March and April will bring to the maple woods in the Buckeye State, but this year’s cold grip of winter and late start highlights one important principle of research. Because of variation, multiple years of data are necessary to make reasonable research conclusions – so we are in it for the long haul! Happy sugaring!!
When it comes to selecting a fuel source for your evaporator, operators should choose based on efficiency, not convenience. To convert 2% sap into 66 brix syrup, 400,000 BTU are required – this is constant for all fuel sources. The two most popular fuel sources, in today’s maple world, are wood and fuel oil. Additional choices include natural gas, liquefied petroleum (LP) gas, and various wood products such as pellets have been adapted to fuel maple evaporators.
I created the above figure based on estimates generated from the Southern Maine Renewable Fuels Institute. Based on the statistic above – 400,000 BTU are required to produce a gallon of syrup – I derived production cost estimates for each fuel source and compared burner efficiency. Fossil fuels have a slight edge when it comes to fuel efficiency. The reason they are so efficient is based on the type of burners used and the ability to extract a higher percentage of heating units from each fuel source.
How do you choose the right fuel source for your maple operation?
The ambiance of making syrup on a roaring wood fire has never been challenged. Wood is by far the most popular fuel source for evaporators. It is readily available. And most producers look at dead wood scattered about the sugarbush as something that needs to be disposed of anyway. For that reason, the true value of wood is seldom considered. As we will see later, the value of wood is very close to the value of fuel oil when it comes to making syrup. The true value of wood is based on the dollar value of cordwood. There is an old saying “cordwood has no value until it cut and stacked.” Its value is representative of your time and labor.
A standard evaporator will produce 22 gallons of syrup from a cord of dry wood. Without the major advances in wood burning technology, most open evaporators are rated at 40-60% efficiency. Heat units are lost at multiple locations across the evaporator. You can quickly see why many producers made the shift to more efficient oil evaporators even though they now had to pay for fuel. The efficiency of a wood-fired evaporator is in the design. No matter what the design, the basic principle of operation remains the same. A wood-fired evaporator draws heat from the flame produced in the firebox. The heat consisting of flame and burning gases is drawn by air movement under the pans and out the stack. The arch is designed to pull and lift the flame up a moderate incline eventually compressing the heat into the flues of the rear pan. The heat exits the evaporator through the stack at temperatures of 600-800 degrees F. Stack dimensions must be designed correctly for proper draft. Wood needs to be placed in the evaporator to facilitate maximum heat without choking the air and dampening the flame. This usually means the firebox should not be filled to the top. You need to allow space for air to enhance the flame. The wood should be fired at regular intervals. A general recommendation is every 5 minutes.
There have been many changes in modern wood arch design that increase the overall efficiency of the evaporator. Forced air injection along with highly insulated arches and firing doors make the modern wood-fired evaporator as efficient as their oil-fired counterparts. Some are rated 85-90% percent efficient. Such high-performance levels are the result of being able to totally burn the wood that is loaded and the ability to re-burn gasses given off during the combustion process (gassification).
Fuel oil is another popular choice among maple producers, and there are several reasons for this. Fuel oil burns clean and hot and is an ideal choice for larger operations that require high volumes of fuel. This logic has been tempered in recent years with the increasing use of reverse osmosis to produce high Brix concentrate and reduce fuel demands. Efficiency is relatively high nearing 80%, and 1 gallon of syrup can be produced for under 4 gallons of fuel oil.
Unlike wood-fired arches, oil-fired evaporators require a minimal draft. Oil-fired arches are designed to develop radiant heat. The burner flame creates a ball of radiant heat and that heat then hovers beneath the pans. Temperatures in an oil arch can reach 1000 degrees F. The movement and intensity of the heat is controlled by a barometric damper that restricts the movement of air through the stack. The damper maintains a uniform temperature by controlling the airflow thru the evaporator. If this control device is not present, the heat can quickly be lost up the stack and the performance of the machine will be impaired. The burner nozzle size and fire rate determine the intensity of the heat. If everything is working correctly, the flame will burn cleanly and the flame ball of burning fuel oil will be suspended in the middle of the fire box never touching the sides of the arch.
Natural gas is very similar to fuel oil. In fact, the burners today are very similar in operation. Natural gas is convenient and is probably a cleaner source of fuel than oil; additionally, efficiency mirrors fuel oil. Though the original natural gas burners were often inconsistent resulting in hot and cold spots across the pans, there is now little difference in performance as compared to oil-fired evaporators. The biggest drawback is the availability of natural gas. Unlike oil that can be hauled to a remote location, gas needs to be piped in and is not readily available everywhere. If you are fortunate enough to have natural gas available, it is an excellent fuel option.
The biggest drawback for oil and gas is the variability in cost as the oil market fluctuates. In 2020, we are living in a down cycle for oil and gas and prices are more appealing entering the 2021 syrup season. Within a few years, that could be a completely different story. Time will tell.
I would be remiss if I stopped the article there.
Regardless of what fuel source you choose for making maple syrup, the best single investment a producer can make is to add reverse osmosis to their operation. Despite the high initial cost of reverse osmosis, the cost of processing syrup is reduced significantly and the pay-off is long-term. Reverse osmosis not only allows a producer to process sap quicker, but it also opens the door to expand one’s operation. The savings on fuel are obvious. Before ROs, as reverse osmosis is commonly called, became popular the size of the operation was limited to the amount of sap that could be boiled on an evaporator. The only way to add capacity was to add evaporators, and some of the larger operations were running four, five, and even six to handle peak sap flow. Today, those same operations now employ modern RO systems with multiple membranes that can handle sap coming from thousands of taps. And using less time and space to do so. Reverse osmosis revolutionized the North America Maple Industry.
In this final post of the evaporator series, we will examine a few remaining factors to account for when considering the boiling process for maple syrup. As you will see, a few instruments enable the necessary precision to ensure a high-quality batch of syrup every time.
Barometric Pressure Matters
One of the biggest factors influencing the boil in an evaporator is barometric pressure. Barometric pressure and weather fronts are frequently responsible for the day-to-day erratic behavior in the way sap boils. The boiling rate is directly associated with the barometric pressure on any given day. If you experience a high barometric pressure, sap boils faster; with low barometric pressure, the boil slows. Meteorological shifts can happen several times per day, and whenever pressure fluctuates the boiling point of water (212 F) will vary. Producers must adjust their thermometer to accurately produce syrup consistently at 219 F. Make sure you calibrate your thermometer in boiling water before the start of each boil and throughout the day as needed. A thermometer will give you a ballpark reading, but to get ultra-precise and guarantee 66 Brix syrup of the highest quality, additional instruments should be utilized.
Having the Right Instruments
You will choose one of three instruments to determine your syrup density coming off the evaporator. Only one is the best and most accurate for reading syrup straight off the evaporator. As previously stated, syrup’s finishing point is 219 Fahrenheit, 7 degrees above the boiling point of water. Because barometric pressure influences boiling point, using only a thermometer can result in inconsistent finished syrup density. One better option is to use a refractometer, but the syrup sample has to be temperature-stable and filtered to get an accurate reading. For this reason, we do not recommend using a refractometer on syrup coming directly off the evaporator for obvious and practical reasons. (Refractometers are, however, the instrument of choice for measuring the density of cooled and filtered syrup during canning).
The most recommended instrument to determine the density of hot finished syrup is the hydrometer. A hydrometer should be floated in a sample of finished syrup that is at least 211 degrees F. Hydrometers have two lines, one for cold and one for hot. You will use the hot line for your syrup density determination straight off the evaporator. Bring the instrument up to eye level or set it on a stable object close to eye level for the most accurate reading. The hydrometers red line should float even with syrup level in the container. Most hydrometers also have two scales, one for Brix and one for Baume (Baume measures specific gravity of a solution). The Brix scale is the most popular and frequently used today. Avoid letting scale build up on the outside of the glass as it will impact the density reading, and producers should regularly validate their hydrometers for accuracy. Once you confirm finished syrup of the proper density, you will filter your syrup for clarity and to remove niter. You can then use a color comparator to determine the grade of your syrup.
The evaporator has become the center piece of many maple operations. It is the first thing visitors see in your sugarhouse no matter what time of year they visit. It is also one of the most essential pieces of equipment in your operation. After all the process of making syrup requires that we must heat maple sap to 7 degrees above the boiling point of water to produce pure maple syrup. This results in the caramelization of maple sap into maple syrup. The addition of heat to maple sap results in the amber color we desire and the maple flavor we love.