Pre and Post Season

Another Topsy Turvy 2023 Maple Season

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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.

Tips for Working Volunteers into Your Maple Woods

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Whether you have children eager to help or new volunteers wanting to participate in your woods, you are undoubtedly familiar with the tug-of-war.  On one side, you want to get new hands engaged and interested.  On the other hand, if you want something to be done right the first time, do it yourself!  At the Ohio State Mansfield sugarbush, I am constantly balancing the need to get volunteers into the woods while still maintaining standards of quality and efficiency.  Here are a few tips that we use to make sure our volunteers are a help and not a hinderance.  Hopefully you can use one or more of these ideas to streamline your own efforts to reach this delicate balance.

Precision tappers are expensive, but precision tappers are also efficient and effective at controlling the single most important activity in your woods – tapping!  Precision tappers allow you to set the exact tapping depth and reliably expect that the grip points on the end of the device will result in a steady straight taphole each and every time.  While they are costly, our taphole consistently went through the roof when we employed these this sap season for the first time ever.  Precision tappers are probably not for the average producer, but if education and outreach is a central part of your mission, they may well be worth the cost.

An extra step for ensuring excellent tapping is to clearly mark your tapholes at season’s end with a dot of forestry paint.  If you are employing geometric tapping (e.g, over 3 inches-up 6 inches, over 3 inches-down 6 inches, …), then next year’s instructions simply become “find the [insert color of your choice] dot, space over, and tap.”

While we are on the subject of tapping, choose a sacrificial tree to train your tapping crew.  This double-trunked specimen is below our sap shed, has half its crown busted out, and has been tapped no fewer than 100 times in the past 5 years.  Our sacrificial tree is a classic “take one for the team” scenario.  Drilling a good taphole is only part of proper tapping.  How to properly set the spout is just as important, and in my experience, more apt for abuse and mistakes.  Repetition with back-and-forth feedback are minutes worth their weight in gold if volunteers or new help tap a significant portion of your woods.  Make your mistakes here – not on your production trees.

Lead by example in the sanitation department.  If your sap tank is filthy and scummed over, it’s hard to expect your help to take you seriously about sanitation in the rest of the woods.  If your tapping gear is mud-caked and filthy, it’s probably a bit hypocritical to expect your volunteer crew to keep your gear spotless and spit-shined.  Be diligent about sanitation, speak often about sanitation, and your help will take sanitation seriously as well.

Keep a volunteer’s job simple but always give them a roll of flagging tape to pinpoint potential issues they may run across.  If they see something suspect, have them tie up some flagging tape so you can check it out later.  Better yet, and particularly useful for keeping track of progress and directions in the woods, if you incorporate some numbering system into your main lines and laterals.  Below you’ll see an aluminum write-on tag that we tie on each lateral loop starting with main line number and ending with lateral line number.  So in this case, you’re looking at the 3rd lateral line on main line #1.  Navigation and giving directions becomes exponentially easier with this numbering system in place.

While we are talking about lateral loops, show your volunteers the rapid visual checks a producer has to ensure their woods are working properly.  As volunteers walk the woods, it’s easy to visually confirm that sap is traveling around the loops signaling a functioning system.  The same goes for sap flow through the drops into the laterals.  If the loops or drops are empty but the rest of the woods is running good, a strip of flagging tape might be warranted.

And lastly, do not realistically expect perfection.  I found this double spout tree untapped just last week.  It’s too bad we didn’t get this one tapped earlier, but if 1 big tree’s production is the price I pay to get someone excited about maple – that’s a price I suppose I’m willing to pay.

Getting Ready for Season

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These are exciting and anticipatory times in the sugarbush as last-minute items are checked off the list.  As that list gets shorter by the day, we are turning our attention increasingly to the weather forecast and the all-important decision of “When to tap?”

Smart sensors are installed and grabbing what precious little sunlight has shone this January.  Charge batteries, CHARGE!

Lateral lines are all patched and tight with new spouts on the end of each drop.  These little side pulls, constructed from old, chewed laterals, have been a big help to us in tightening up our system.  First a before photo, second an after photo, and third a zoomed in photo of the side pull rigged with double end line hooks.

Additionally, a small pocket-sized carpenter’s level is worth its weight in gold for ensuring you have continuous drop from spout through lateral to main line to the pumphouse.

After an exceptionally windy and raucous 2022, we revamped and strengthened our sap tank cover.

An old broken valve has been replaced by new hardware (valve with the white handle is the new replacement), and I even took a little hacksaw to knock the end of one handle off to get a bit more clearance.

The next big to-do list item is to get our research canisters sledded out into position.  A fresh 3-5 inches of snow will make that task bunches easier.

Hopefully you are whittling down your checklist, or if you are a producer from southern Ohio or neighboring southerly state, you may already be making some syrup!  Heck, even as far north as Vermont, early tappers are getting a sap run already.  Hopefully this early warm spell is not indicative of yet another roller coaster season, but regardless – Wishing You a GREAT Season!

Fall Maple Assessment – Get Ready for Next Season, Part II

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Read the first installment of our autumn mini-series “Get Ready for the Season” here.  The first article focuses mainly on the woods, and Part II sticks to the sugarhouse.

It is perfectly natural after a long hard season to put off sugarhouse cleanup and maintenance. This can be a major mistake. Getting the sugarhouse ready for the next season starts immediately after last season has concluded.  Dirty unmaintained equipment sitting around in warm weather can promote the worst of unsanitary conditions that will surely haunt you into the upcoming season.

Let’s start with storage tanks. Not everyone can afford bright shiny stainless-steel tanks that are easy to clean. Many producers substitute more affordable plastic tanks. Unfortunately, plastic tanks have earned the reputation of lowering syrup grades due to rapid microbial growth. All of the elements for rapid growth are present. The sap supplies the food and the tanks warm quickly. Where do the microbes come from? They are hiding in the porous interior of the tank. That porosity is what makes it almost impossible to thoroughly clean a plastic tank. You may get by for two or three years but sooner or later the tanks will have to be scrapped. The cost of three or four plastic tanks over a ten-year period can add up quickly. Consider the economic value of a stainless tank that should last forever if handled and maintained properly.

Reverse osmosis (RO) has revolutionized the dynamics of the maple syrup industry. For the commercial producer, the RO has drastically slashed labor and fuel expenses. When it comes to maintenance, the most critical element is maintaining the primary filter or membrane. Membranes that are not maintained properly can be severely damaged. Damage can lead to the passing of sugar into the permeate tank. This results in a hidden loss of profits going down the drain. Always check your permeate for abnormally high sugar content. Washes of both soap and acid are used in the cleaning process followed by an extensive permeate rinse. A properly maintained membrane should last for many years. Another critical but oft overlooked issue are increased levels of chemicals being discharged from the sugarhouse. When you are using an RO, you are discharging thousands of gallons of liquid through your sugarhouse drains. You are also discharging acids and soaps through the same drain. If possible, neutralize the chemicals by bringing both acids and soaps back to a neutral 7.0 pH before you flush them down the drain. Neutralizing agents are readily available from your maple dealer.

Producers tend to overlook where and how they store there concentrate before boiling. When you concentrate sap, you are creating the perfect storm for a microbial outbreak. You are doubling, and in some cases tripling, the amount of sugar in the tank. When you run the sap through an RO you also boost the concentrated sap’s temperature by at least 20 degrees Fahrenheit. Assuming the concentrated sap is housed in a relatively warm sugarhouse, it makes no difference if you are using a stainless or plastic tank, microbial populations always explode in concentrated sap. The first line of defense is to boil the concentrate as soon as you can to prevent grade deterioration. If you only have enough money to purchase one stainless steel tank, make the purchase for your evaporator feed tank. This is doubly true if you are concentrating with reverse osmosis.

One of the best maintained pieces of equipment in any maple operation must be the evaporator. After all it is the center piece of most sugarhouses. Producers tend to take pride in how their evaporator looks inside and out. Here are a few things to consider before you start the season. Make sure all of the fittings and gaskets are functioning properly. It is good idea to do a test boil before using. You do not want to waste sap or concentrate if there is a malfunction. During the season, always start each day with clean niter-free syrup pans. Do not let niter build up. Excessive niter can cause a pan to overheat and even burn. Make sure you are using defoamer properly and in the proper place. If you are going to be shut down for a long time due to a warm spell, plan on draining your pans to prevent microbial buildup. Attempting to keep the liquid on the evaporator will only lead to contamination of fresh sap when it arrives and the production of poor-quality syrup. In a freezeout situation, make sure to inspect your pans to make sure they are not freezing solid. If they are, light a fire and thaw out your pans so they do not break. Again, emptying the pans is not a bad idea. Along with your evaporator make sure your filter press and auto-draw off are functioning properly. Improper maintenance of your evaporating and filtering equipment can result in the production of poor-quality syrup that will cost you money in the long run.

After the season, make sure everything is cleaned and stored properly. There are many ways to clean an evaporator and it comes down what works for you. Avoid using any kind of detergent in the cleaning process. Hot water and elbow grease wins out every time. At the end of the season, make sure your syrup is stored properly. There is nothing worse than opening a barrel of your top grade, only to find out it has spoiled. Syrup is best stored in a location where it stays below 70-degree Fahrenheit. Even though you hot pack your syrup it is wise to roll the drums, if possible, several times during the offseason. This agitation helps eliminate moisture condensation from collecting at the top of the drums due to temperature fluctuations.

If you are planning to upgrade your sugarhouse, keep in mind that this is the best time to make sure your facility can pass a state or federal inspection. All of the rules and regulations are available online through OSU Extension.

You have now done a comprehensive evaluation of your sugaring operation. What are your most cost-effective “low hanging fruit” items? Act now – season will be here before you know it.

Fall Maple Assessment – Get Ready for Next Season

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The leaves have changed and have mostly fallen from the trees.  In some corners of Ohio, the first snow has already fallen.  For maple syrup producers, that means the push to get ready for a new season is upon us.  This is the best time of year to walk through your entire operation and systematically appraise your operation.  Now is the time to walk your sugarbush with a notebook in hand.  This assessment process allows you to locate the little things that make a big difference when the sap starts flowing.

Begin by looking at the most logical place first – your trees!  What condition are the trees in?  Are they healthy?  Did the June storms cause wind damage to the crowns?  The health of the trees will determine the number of taps per tree, and to some extent, the depth of your taphole.  If trees appear stressed, consider tapping a bit shallower (1.5 inches) rather than the full 1.75” or 2” depth.  It is not unusual to rest a tree for a season, allowing it to overcome obvious stressors.

Now reflect on your tubing system’s performance the very first year it was installed.   Compare that year to the way your system performed last year.  Have you noticed a drop-off in performance? It is easy to blame a poor season on the weather; in reality, the cause could be the age of your system and some neglected repairs.  For many producers, the first inclination is run out into the woods looking for squirrel chews and start repairing lines.  Do not get me wrong, that is important, but it is just one stage of a more holistic leak detection process.  The first order of business should be to inspect the lines for more systemic degradation and disrepair.  I hope that everyone is starting every season with all new spouts?!  However, your assessment should look deeper still.

When was the last time you changed the drops?  How long are the drops?  Are they long enough to allow you to reach around the tree?  Thirty-two inches is a good starting point for drop length in established systems.  What condition are your tees in?  Bad tees lead to micro leaks that sometimes are worse than squirrel chews because they are harder to locate and might be ignored an entire season.  What condition are your laterals?  Do they need to be replaced?  Are you noticing a mold buildup in the lines?  Are your lines patched together because of multiple repairs and damage?  When you replace laterals, it is a good time to look at the overall layout of the lateral system?  Count your taps on each lateral to determine if one is overloaded.  Remember, any given lateral should only be carrying 5 to 7 taps.  Also look at the slope of each lateral.  Is it running straight and tight and downhill for best performance?  What about your saddles, are they leaking?  Old saddles, just like old tees, need to be replaced on a regular basis – at least every 5 years.  Old saddles are often one of the major causes of leakage in maple tubing systems.

The next area of concern is the mainlines.  Ultraviolet light and wind damage are major causes of stress on mainlines.  Mainlines are good for 10 to 15 years, but eventually they must be replaced.  Yes, that is an expensive project!  However, the benefits outweigh the cost.  Installing new lines also allows you to remove damaged and unwanted trees during the repair.  Sugarbush stand improvement is important as it will improve the overall health and productivity of your sugarbush in the long-term.  Hazard trees, such as standing dead ash, should also be dealt with during a mainline replacement project.

It is easy to see how performing a pre-season assessment of your tubing system can be beneficial.  And that is just the tubing system!  After you walk your sugarbush – clipboard in hand – go back to the sugarhouse and develop an improvement plan. What must you buy?  In what quantity?  When will it arrive?  Are their supply chain delays?  Rank everything you have found in order of importance and start chipping away at your list – sap season will be here before you know it!

Sugarbush Storm Damage

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There’s a mainline hiding under there somewhere!

Many Ohio producers experienced damage – some slight and others major – during the derecho that sliced through our state overnight on June 13th.  At the Ohio State Mansfield sugarbush, we thankfully escaped what I would call major damage, but the storm did knock down 30 or 40 trees throughout our woods.

As temperatures start to cool in another month, I hope to get most of the clean-up work done before the crunch of late fall turns into New Year’s panic with the 2023 season breathing down our neck.  For woods like ours, 2 or 3 days of cutting should clear most of the damage.  For others however, hard decisions are being made as the devastation was on a tragic scale.  I recently spent a couple hours in the historic Malabar Farms sugar woods and could not believe my eyes.  Unfortunately, their scenario is not an isolated one.

Whatever your circumstance, be safe out there as you tackle storm damage.  Downed and twisted trees are unpredictable.  If in doubt, don’t.  Don’t be afraid to hire an expert.  Always work with a partner.  Always wear your PPE.  Work with sharp saws.  Document your losses, you may find that damages can be leveraged as a tax reduction claim.

And most of all – BE SAFE!!

Participate in the USDA NASS Census

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Thanks to Gary Graham of Ohio State University Extension for writing this article.  We have broken it in two parts, but both installments end the same way – with an urge to sign-up, participate, and be accounted for in the USDA NASS Census.  Last week’s first installment focused on what the USDA NASS Census accomplishes and why it is so crucial to participate.  This week, Gary emphasizes why your participation is so important and addresses common misconceptions that hold producers back from contributing.

 

Why should you report?

Would you like to make more money for your production efforts?  Do you like to obtain the latest information and research to help your production process be more efficient?  Would you like to receive assistance making you more economically competitive?  Are you interested in increasing the likelihood that your kids or the next generation will be able to continue to farm?  These and many other direct and personal questions could be asked, and they are all answered by each producer taking their responsibility seriously by reporting production volumes to NASS.  Besides being a civic duty, a federal law requires you to respond to the Census.

My neighbors do not participate because of their cultural beliefs.

We live in the greatest country on earth where we have so many freedoms and choices.  Religious freedoms are a pillar of the foundation our country is built on.  Replying to NASS’s request for information does not infringe upon one’s religious or cultural beliefs.  Participating in the Census merely gives a true accounting of the volumes and values of each commodity in our great country.  Just because you chose to not take advantage of the financial benefits or programs resulting from the Census, you are still bound by law to participate and hurting yourself by not being counted.

My operation won’t make a difference.

Actually, it does.  “Since 1975 a farm is defined as any establishment from which $1,000 or more of agricultural products were produced during a year.”  A little harsh to say but here it goes: “If you’re not a big enough commodity to be counted then you are not important enough to receive help.”  Hundreds of billions of dollars are annually distributed to states based on the information collected from the Census.  These dollars go to improve markets where your products are sold.  Promoting your commodity to consumers.  Providing research and education dollars to help bring the latest knowledge in operation efficiency assisting you in making a better living. It gives you a competitive edge over cooperate farms.  It gives the next generation help to keep agriculture growing.  So YES, it does matter when you don’t report your production.  It hurts you, it hurts other producers, and it hurts the next generation of producers.

I do not know what to do.

It’s easy.  First you need to get signed up so you can be surveyed.  NASS cannot directly visit every person producing an agricultural commodity and ask them to participate.  NASS relies on the honesty and cooperation of producers to voluntarily sign up.  Again, I can’t stress enough this will never open you up to other surveys or government agencies.

 

Before June 30, 2022, sign up for the USDA NASS Census here.  Once signed up, you will receive a Census through the mail in November 2022.  Your completed census needs returned before February 2023.  The data will be analyzed and the results reported in early 2024.

 

Commodity Producers: Your Census Participation is CRITICAL

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Thanks to Gary Graham of Ohio State University Extension for writing this article.  We have broken it in two parts, but both installments end the same way – with an urge to sign-up, participate, and be accounted for in the USDA NASS Census.  This first installment will focus on what the USDA NASS Census accomplishes and why it is so crucial to participate.  Next week, Gary emphasizes why your participation is so important and addresses common misconceptions that hold producers back from contributing.

NASS Graphic Color (JPG)

“The Census of Agriculture provides the only source of uniform, comprehensive, and impartial agriculture data for every county in the nation. Through the Census of Agriculture, producers can show the nation the value and importance of agriculture and can influence decisions that will shape the future of U.S. agriculture.  Response to the Census of Agriculture is required by federal law.”

In 1790, President George Washington ordered a Census, counting 4 million Americans on farms.  In 1791 he surveyed famers within roughly a 100 to 250 mile range from the then Capital.  Those farmers surveyed were asked about crops, yields, livestock prices and taxes.  Washington proposed the National Board of Agriculture, but congress rejected it.  The 1840 population Census requested the first detailed agriculture production numbers.  Not until 1862, President Abraham Lincoln established “The People’s Department” which is todays United States Department of Agriculture (USDA).  In 1863 the Division of Statistics was established, and this would evolve into today’s National Agricultural Statistic Service (NASS).  If you did the math that is 232 years for population Census’s and 182 years that an agriculture Census has been taken, yet many people do not know about it, nor participate and fail to see the value of this important process. This year (2022) is a Census year and producers need to understand the importance of their participation in the Census of Agriculture.

Let me start with the largest myth and misconception about Census participation.  The Internal Revenue Service (IRS) will come after me and raise my taxes.  Nothing is further from the truth.  Due to the delicate nature of the data NASS collects, they have one of the strictest protocols for data protection.  NASS in bound by law (Title7, US Code, and the Confidential Information Protection and Statistical Act) to protect private information.  Meaning NASS can never release personal information to any person, organization, nor government agency.  NASS only publishes aggregated data (summarized) and never individual or farm-specific data.

Many producers attitude is that their production information is “for their eyes only” or “nothing in it for me” to participate in the Census.  Again, nothing could be further from the truth.  Not being counted and reporting production hurts every producer.  Rumors and conspiracy theories hurt as they spread lies and false accusations about big brother watching you.  Many misconceptions have been heard over the years and none are valid nor true.  What is true is not everyone participates, and it is hurting agriculture across Ohio and the whole country.

Before June 30, 2022, you need to sign up at the USDA NASS website.  Once signed up, you will receive a Census through the mail in November 2022.  Your completed census needs returned before February 2023.  The data will be analyzed and the results reported in early 2024.

2022 Maple Season Forecast from a Climate Expert

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Please join us at 7:00 PM, Thursday January 13th to learn from OSU Extension’s Aaron Wilson about how weather, climate, and maples interrelate.  His talk has immediate implications for this current year’s sap run and a long ways into the future.  Those of you that have heard Aaron speak before know that it is a real treat to learn from his expertise.  Register here at the Woodland Stewards website.

Dr. Aaron Wilson is an Atmospheric Research Scientist with the Byrd Polar and Climate Research Center and Climate Specialist with a joint appointment in OSU Extension.  He will shed some light on how the coming maple season may turn out.  Dr. Wilson’s presentation will include the 2022 short-term forecast as well as how our changing climate may alter maple production in the future.  Future climate projections pose significant challenges to the future of maple production across southern maple producing zones.  Planning for the future and considering how best to meet those challenges is crucial for sustained maple production in the long-term.

Synopsis:  From increasing winter and spring temperatures to extreme weather events, climate change poses a risk to the maple syrup production community. These changes alter short-term conditions like quality and quantity of sap, while long-term changes in climate are having impacts on the health of trees, roots, and shifting areas where production is viable. Projections of future climate pose significant challenges to the future of maple production across southern zones. How might the community plan for and mitigate these impacts? Join us as we explore the influence of weather and climate change on the maple industry and discuss the implications for the future.

Register TODAY!

Optimizing the Performance of My Vacuum Tubing System: Part I

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The goal of these next 3 articles is for you to realize that there are many factors that go into installing and running a maple vacuum tubing system. All the factors are interrelated and each one needs to be careful considered on the part of the operator.  The below information is contained in the Cornell New York State Tubing and Vacuum System Notebook (NSTVN) written by Cornell University’s Maple Specialist Steve Childs.  Much of the information is this and the next two posts is a synthesis of past content with some more recent best practice guidance.

When we talk about tubing systems, we have two roads to travel. One is a gravity system and the other is a vacuum system. A conventional 5/16” gravity system is not much different from running sap into a bucket. The yield is much the same as collecting sap in a bucket. When we add vacuum to a tubing system, we increase the sap yield 5% for every inch of vacuum we generate in our system. For example, if we produce 15 inches of vacuum in a line, we should be able to almost double our sap yield.  The first year after installation is always the best. As time on a system accumulates, wear-and-tear hampers performance.

Caption: Year 1 Production with a Brand-New System Should Provide Your Best Vacuum Levels

The definition of vacuum is the absence of air. The maximum level of vacuum achievable on any given day is determined by the barometric pressure. This means that our vacuum level can never exceed the barometric pressure in the location of our sugar bush. There are two way to measure vacuum pump performance, Inches of Mercury (hg) and Cubic Feet per Minute (CFM). Inches of mercury measures the negative pressure produced when air leaves the line. For example, if 50% of the air is removed then the inches of mercury should be somewhere between 14 and 15. At 25 inches of mercury, approximately 85% of the air has been removed from the lines. CFM on the other hand measures the amount of air being evacuated from the lines in units of cubic feet per minute. This is the amount of air that a vacuum pump is pulling out of the system in one minute’s time. Where is the air coming from? The answer is gas that is forming inside the tree and being expelled through the tap hole. As a rule of thumb, there is a 1 CFM requirement for every 100 taps on the line.  However, the biggest contributors are leaks allowing air to enter the system through damaged or aging tubing. This statement emphasizes the importance of managing leaks in a vacuum tubing system.

Caption: Vacuum Gauge Measuring Vacuum in Inches of Mercury (hg)

Speaking of leaks, the most important part of operating any maple syrup system is the time you spend in the woods making sure your vacuum tubing system is leak-free. Much of the rest of the article is spent discussing different technologies and equipment, but the simple fact of the matter is this – the best equipment with poor care in the woods won’t do you a lick of good when it comes to putting more maple syrup on tables of your customers. You must always account for leaks that introduce air into lines. You might be able to maintain peak vacuum on average days, but your system will show its weak points when sap flows are running fast and you need to move as much as air as fast as possible to maintain vacuum levels. Being able to spot and repair leaks quickly is essential. To accomplish this, you should design your system so you can isolate lines to pinpoint problems. This can be done by compartmentalizing your system with valves and vacuum gauges placed at the starting point of each line. The installation of a tubing monitoring system can be a wise investment as well, and the time saved and extra sap produced will pay for the cost of the upgrades in short order.

Back to our lesson on vacuum and barometric pressure. There are factors that have a direct effect on barometric pressure. One is altitude. As the altitude increases the maximum barometric pressure declines (rule of thumb: for every 1000 feet of elevation you lose 1 inch of vacuum). For example, at sea level, or 0 altitude, the average barometric press can be 29 inches; at 2000 feet, the average maximum barometric pressure obtainable is only around 28 inches. In addition, barometric pressure changes under different environmental conditions, and variations in barometric pressure caused by atmospheric changes can occur multiple times in a day. If we are running a vacuum pump under a low barometer at 2000 feet elevation, we might struggle to maintain 28 or even 27 inches of vacuum on a very tight well-maintained tubing system.

Sap moves down the line by gravity on a system of tubes suspended with wire. The basic components are spouts, tees, and drops moving sap from the tree into lateral lines. A lateral line should have no more than 5 to 10 taps per line and should be no longer than 100 feet in length. The lateral lines flow into main lines. In large systems, secondary mains flow into Wet-Dry lines and or trunk lines (large diameter lines) that move the sap to a central collection point.   To properly function, sap lines should be straight, pulled tight, and sloped downhill. To this point gravity systems and vacuum systems are similar, with the gravity system relying on slope and Newton’s law of gravity to move the sap.

Caption: 65 CFM Bush R-5 Vacuum Pump

When vacuum is added to the system, sap flow is aided by the movement of air.  The components of a vacuum tubing system are the vacuum pump, which is connected to lines via a sap releaser. Even though it is called a vacuum pump, it is not a pump in the conventional sense of the word and that is a bit confusing. A conventional pump moves liquid creating pressure ahead of the liquid and suction on the backside of the liquid. There are other types of pumps used in maple production. For example, a diaphragm pump is a conventional pump and that creates enough suction (secondary vacuum) to draw sap from a tree. However, if liquid is not present in the lines that suction can be lost.  A true vacuum pump moves air, not liquid and it creates a higher level of vacuum (absence of air) as the air is removed from the lines. That level of vacuum can be maintained with or without sap in the lines and will only drop if a leak allows outside air to enter the line.  Because the pump is designed to move only air, the liquid must be separated from the pump. This separation process is performed by a sap releaser. If sap enters the vacuum pump severe damage to the pump can occur! To prevent this from happening, a moisture trap is placed between the pump and the releaser.

Caption: Sap house releaser (right) with Vacuum Piston Pump (left)

A properly sized vacuum pump with a proper CFM rating will be capable of removing air faster than it is introduced. However, there is one factor that can interrupt and slow that process – line size. Vacuum lines are designed to conduct air to the pump. If your line diameter is too small, the air movement will be restricted requiring more time for the pump to clear air from the lines. This phenomenon is referred to as line loss. The smaller the line the more the air flow is restricted resulting in higher line loss. As an example, a 60 CFM pump set at 15 inches of vacuum hooked to a 3“ line can maintain over 40 CFM out to 5000 feet. However, that same pump hooked to a ¾” inch line is incapable of delivering 15 inches of vacuum at 2500 feet from the pump. Line loss increases the time (recovery time) needed to evacuate air from the line and restore peak vacuum level.

What is missing from this equation? The capacity of the line to conduct liquid. Every diameter of pipe has a maximum liquid capacity. The size of the pipe that is needed is determined by the number of taps flowing into the pipe. Each tap during a peak flow might contribute upwards of 0.2 gallons of sap per hour. Once you calculate the amount of sap flowing in you can determine the size of the pipe that is needed. There is however one caveat, the steeper the slope the faster the sap moves through the line thereby effectively increasing the capacity of a given-sized line on steeper slopes. Slope can also influence sap flow in other ways. The portion of the line, 50 feet or longer with the least amount of slope, will strongly influence sap flow. Examining this critical portion of your line might dictate a necessary increase in line diameter to allow for adequate air and liquid flow. Remember, you need to move air as well as liquid through a maple pipeline. To do this you must maintain the proper ratio of air to liquid inside the line so as not to inhibit sap movement. If you look at a working cross section of tubing it should contain 60% air and 40% liquid. This is a primary consideration when determining what size of line to use in your sugarbush.  If the liquid level increases beyond that ratio or is uneven (wavy), the air movement will be restricted resulting in a drop in vacuum.

Caption: Whip Connection to a Wet-Dry Line.

There are two ways to solve this problem. The first would be to increase the size of your main lines but 1 ½” inch and 2” tubing is expensive, and it adds to the overall expense of the tubing system. Still, increasing tubing size may be justified if you have a large number of taps coming into a trunk line. The other alternative is to install a dual-line conductor commonly known as a Wet-Dry Line. Composed of two lines of equal size (or a dry line slightly larger than the wet line), a Wet-Dry system can excel at moving sap across flat areas or areas where multiple secondary mainlines merge. Secondary mains may enter the Wet-Dry line at a booster, or a line configuration called a whip. This allows sap to move down the wet line without impeding the airflow in the dry line. This set-up is particularly useful in flat areas where slope in minimal and sap flows slowly which may inhibit the necessary amount of air flow. Wet-Dry lines can be a cost-effective way to move sap through areas of minimal slope.

Stay tuned for Part II in a couple of days and be sure to leave questions or comments!

Author: Les Ober, Geauga County OSU Extension