COOPERATIVE EXTENSION SERVICE • UNIVERSITY OF KENTUCKY COLLEGE OF AGRICULTURE, LEXINGTON, KY, 40546

FOR-118

Agroforestry Forest Farming: Have Maples, Will Sugar…

Deborah B. Hill, Department of Forestry

All over Kentucky, but probably especially in the eastern part of the state, woodland owners may find that they have many maple trees in their woodlots. If these trees are larger than 10 inches in diameter, and if there are 25 to 40 maple trees per acre, wood- land owners might want to think about making maple syrup as a possibility for increased income from their woodlots.

aple syrup has been produced One of the greatest annual maple How does one identify Min the United States since be- syrup productions on record was a tree that will produce fore Europeans arrived on this just over 4 million gallons in 1860! a lot of sap? continent, so much information This production was exceeded only has been printed in many different during World Wars I and II, when The things you are looking for in forms. New England, New York, Ohio, wartime activities made it difficult a good sap-producing tree are not Pennsylvania and Canada have been to get cane sugar. However, once necessarily the same kinds of things making syrup for market for many cane sugar became easily available you would be looking for in a good decades. Kentucky is not likely to and cheap, the demand for maple timber tree (although maples often become a major syrup producer, syrup declined, and it has become do make good timber). In a “sugar- but producers can find good op- more of a high value specialty or bush” (the term for a woodlot where portunities for producing Kentucky gourmet item since the mid-1940s. syrup production is the major use), or southern maple syrup on a small the trees are widely spaced so that scale, especially as a cooperative or What kinds of maple they will grow in diameter and make what is called a “cottage industry,” trees make the best syrup? large crowns, which is where the meaning small-scale production. food factories (leaves) grow. Trees All kinds of maples (Acer spp.) can with crowns greater than 30 feet in produce maple syrup. The difference What is maple syrup? diameter can produce as much as lies in how sweet the sap is to begin 100 percent more syrup from their Maple syrup is a natural, organic with. (Maple syrup is made from box sap (which can also be as much as sweetener, famous for its use on pan- elder [A. negundo] in Saskatchewan, 30 percent sweeter) than trees with cakes and waffles. It has been used Canada!). The higher the sugar con- narrower crowns. Crowns that are on this continent since people first tent of the sap, the fewer gallons it both broad and deep are the best lived here. It is made by concentrat- takes to make one gallon of syrup. for good sap production. If wood- ing the naturally sweet sap of maple Sugar maple (A. saccharum) and land owners want to manage their trees. Native Americans froze the black maple (A. nigrum) are thought woodlots for sap production, it is sap to concentrate it, but today the to be both the best producers (vol- probably a good idea to work with a sap is boiled down until it thickens ume of sap) and to have the highest professional forester, especially one into a sugary, sweet syrup. It takes sugar content in their saps. Seventy- who knows something about maple many gallons of sap to make one five percent of all commercial maple sap production. gallon of syrup; 40 gallons to one is syrup is tapped from sugar maples. the industry standard, which is why the real maple syrup is so expensive.

Agriculture and Natural Resources • Family and Consumer Sciences • 4-H Youth Development • Community and Economic Development EXTENSION When do you tap maple What tree management numbers would be fairly typical for trees for their sap, and does the owner need maple sap—which is one reason it what weather conditions to do to improve sap takes so many gallons of raw sap to produce one gallon of finished maple are best for sap production? production? syrup). Outside temperature can af- For the northern part of Kentucky, A commercially profitable sugaring fect the Brix measurement, so it is it’s easy to remember to tap between business should have 70 to 90 taps important to adjust (subtract) the Valentine’s Day (February 14) and St. per acre and probably 20 or more “reading” according to the current Patrick’s Day (March 17). Further acres of woodland to tap. If the temperature when taking the sap south, it may be important to start syrup is intended only as a contrib- sample: earlier. It all depends on that cold uting part of the total farm/woodlot night/mild day combination. Howev- income, this process can be done Outside Brix er, it is wise to have all the necessary on only a few acres. Taking care of temperature (°F) adjustment (°) equipment ready any time after the the trees—paying attention to the 32-50 -0.4 New Year. One advantage of tapping guidelines, clearing competition 51-59 -0.3 for syrup is that it is a small “window” from around the sap trees, prun- 60-68 -0.2 of time—usually 4 to 6 weeks—in ing dead branches, etc. —is a good the late winter when other farm- or management practice. If sugaring Re-measure the degree of Brix in the woodland-related jobs may not be starts with most of the usable trees trees that are big enough to tap every demanding too much time. in the 10-inch size class, it will be year. Those whose sap measures less important to thin other trees from than 1 degree Brix probably should How many taps could you around the sap trees so that they not be used. The boiling process uses have in your woodlot? can grow larger diameters in a lots of firewood, so these trees could shorter period of time. Twenty-five Start by getting an estimate of how be cut for that purpose or allowed to thirty productive trees per acre is many maple trees you have per acre. to grow big enough for timber at a good goal to aim for. Ground cover Run a simple transect (straight line a later date. Boiling down the sap (herbs, grasses, etc.) is a good thing, on a compass bearing) and count takes plenty of time, energy and as it is important to protect the for- the number of trees within ten feet resources when the sap has a high est soil from erosion. The park-like of the line on either side for 100 Brix; it doesn’t make practical sense woods that may result from this feet. This will give some idea of how to use more of them all to produce management might look attractive dense the maples are in the woodlot. less syrup! as a place to graze livestock, but the Then measure a sample of the trees animals’ feet compact the soil, and For example, if you boil down 15 gal- at breast height (about 4½ feet from some—horses and goats in particu- lons of 1 degree Brix sap, it contains the ground). To protect the general lar—might also rub the bark off the the equivalent of 1.3 pounds of sugar health of the trees, do not put taps 1 trees. Thinning competing trees and will yield less than ⁄5 gallon of in any tree smaller than 10 inches in from around the sap trees should syrup. Fifteen gallons of 2 degree diameter. The guidelines are: result in trees whose crowns do not Brix sap contains the equivalent of touch, and which should be at least about 2.5 pounds of sugar and will Tree diameter Number 1 yield closer to ⁄3 gallon of syrup. (inches) of taps six feet apart. 10-15 1 How does one measure How does one make 16-20 2 the sweetness of the sap? the sap into syrup? 21-25 3 Sap sweetness is measured by taking The process of making maple syrup 25+ no more than 4 a small sample of sap from each tree from sap has three major steps be- and floating an instrument called fore bottling: It is important to follow these a hydrometer in it. A hydrometer • Withdrawing the sap from the guidelines. Overtapping harms the measures something called Brix, in trees through buckets, plastic trees; undertapping reduces the degrees. The degree measured shows bags, or plastic tubing yield of sap without doing anything that the solution (sap) has the same • Boiling the sap down to a Brix of positive for the trees. density as a solution containing a 55-60 degrees sugar percentage equal to the Brix • Boiling the sap further (in what is measurement (e.g., sap that measures called a “finishing pan”) to a Brix 2 or 3 degrees Brix has a 2 percent of about 66 deg rees (t he minimum or 3 percent sugar content—those Br i x mea surement for market able

2 maple syrup is 65.46 degrees at time, because before heating, the 68 degrees F; the best thickness treated sap is much more dense than [viscosity] and taste is at a Brix untreated sap. of 66-66.5 degrees at the same Look at the trade-offs with any new temperature.) product. Make sure that both costs Tapping the trees is done the same and benefits are carefully calcu- way, regardless of what is used for lated. Once the sap is running, the collecting the sap. The spile is the sugaring operation will demand metal spout that is driven into a hole a lot of attention. Even if the busi- drilled 2.5 to 3 inches deep with a ness chosen is just to collect sap for 7 ⁄16-inch drill bit into the tree. Holes someone else to boil down to syrup, Some basic information on how are drilled at a slightly upward angle the trees must be checked frequently maple trees grow and produce to have gravity aid with the drip- and as the days get warmer it may be new leaves in the spring: The necessary to collect sap from buck- tree leaves are food factories ets, bags, or the large containers that that make sugars as food for the tubing empties into more than once a continued growth of the tree day. Sap allowed to “sit” in collection containers is in danger of fermenting during the growing season. In or becoming contaminated. the fall, when we see the change in the color of the leaves, the If the business is going to continue trees are shutting down their on to the syrup-making process, it is ping of the sap. If trees have been food-producing activities and tapped before, new tap holes need best to have the boiling/evaporating preparing to store food for the to be at least 6” around the tree and equipment in its own structure, usu- winter. Starches and sugars are 4” higher or lower than the previous ally called a “sugar house.” If there tap. The spiles are specialized equip- are no lids on the evaporators, the stored in tree roots for the win- ment for maple sugaring and need to steam is very sticky and needs to be ter, and the trees go dormant. be bought from maple syrup supply in a structure that is well ventilated As daylight begins to increase vendors. Tap the spiles into the drill at the top. If, as usual, the heat source again after December 21 (win- holes gently with a hammer or mal- is a wood fire, good ventilation is ter solstice), the trees begin to a must. Once the process of boil- let and hang buckets or plastic bags prepare for the warm days of ing down is started, it needs to be (also specialized equipment for this spring and the production of purpose) on them, or attach tubing watched carefully. Maple syrup can new leaves. Sap containing the if a gravity-feed or vacuum system be done in batches, but if there is a stored sugars from the roots is being used. lot of sap running, it may be neces- sary to keep sap boiling down to begins to move in the trees. The classic galvanized buckets syrup around the clock. The building Temperatures affect this sap should have covers on them; the can be very simple and should have fl ow; usually a combination of plastic bags used for this purpose a minimum of 4 feet of clearance cold nights (20°-35° F.) and warm usually have a flap to cover where from all sides of the equipment. The days (45°- 55° F.) bring on the the sap is dripping out. Covers keep firebox will need both an air intake greatest activity. the sap free of impurities and con- and exhaust piping. Remember taminants. A vacuum system with that maple syrup is a food product, tubing is the “high-tech” way to so keep the building as clean as go and costs more than the other possible, and keep that necessity sap pan has baffles or flues parallel methods, but it also can change sap in mind when selecting materials to the long sides of the pan in order production from only 5 to 20 gallons to build the sugar house—choose to maximize heat transfer to the of sap per tree per season to 25 gal- materials that clean easily! Storage sap. The sap pan sits over a firebox, lons of sap per tree per season, so it tanks should be located near the where a wood fire is kept burning— may pay for itself in a short period evaporator and must be insulated at as even a temperature as possible. of time. Reverse osmosis is another against severe cold. high-tech method that can be used in (Gas can be used but is more expen- the process—this method removes Boiling down maple sap to maple sive, and if the sugar bush has been 75 percent of the water from the sap syrup is similar to making molas- thinned to improve the crowns of the and therefore reduces the boiling ses from sorghum. The rectangular maple trees, there should be plenty

3 of firewood on hand!). The firebox For best results in maple syrup and half pints rather than quarts should be enclosed, with its own ex- production: or gallons. Know the weight of the haust system, to prevent the smoke • Know the initial Brix of the sap containers and fill by weight rather from the fire creating a smoky taste (use the hydrometer) than by volume, using the 11 lb/gal- in the syrup. • Collect the sap as often as needed lon as the standard. and make sure it is fresh and un- Usually, it takes about 90 minutes Summary for the sap to get thick enough and fermented dark enough to go on to the syrup • Collect and evaporate quickly Making maple syrup from the sap of maple trees in a woodlot is only one or finishing pan. It is best to keep a • Keep equipment clean steady flow of sap and keep it about way to use it profitably and manage an inch deep in the syrup pan, add- What are the rules and it for benefit. Check with a consult- ing it slowly at the sap pan end and regulations for making ing forester or a service forester from the Kentucky Division of For- drawing the syrup off slowly at the syrup for sale? other end. The higher the Brix value estry to develop a management plan The USDA standards for maple syrup of the sap, the shallower the level of for the woodlot. If a sugar bush is are: sap needed in the evaporator and the desired outcome, a management the shorter time it takes to make the US Grade AA (Fancy) plan will show which trees should be cut to benefit the maple trees, syrup from the sap. The boiling point • Color must be the same as or light- and some of the material removed (b.p.) of standard density syrup er than the light amber standard depends on the local boiling point can be used to fuel the firebox used • Clarity must be the same or clearer in syrup making. Good firewood of water, which can be different, es- than the light amber standard pecially at higher elevations. Syrup needs to be seasoned (left to dry) • Weight at 68 degrees F is 11 lb/ b.p. is usually 7 degrees higher than for 6 to 12 months, so it’s important gallon the local b.p. of water. You need to to plan ahead. It is true that for most measure the Brix value often while • Brix is 65.46 degrees agricultural commodities, profit or the sap is boiling and move it on • Flavor is characteristic maple benefit comes as the result of hard to the finishing pan when the Brix flavor work. Maple syrup production is no reaches 55-60 degrees. When the • Syrup is clean, free from fermen- exception, but the intensive work is Brix value of the sap in the finish- tation or other kinds of damage for a relatively short period of time (4 to 6 weeks) and is demanding ing pan reaches 66 degrees, bottle US Grade A it immediately. at a time of year when there are Standards are the same as for AA, fewer other demands on a farmer or If the syrup is produced in batches except color and clarity must be the woodlot owner. Making maple syrup rather than in continuous flow, same or lighter than medium amber. to sell is a good way to sweeten the be sure to clean the equipment income from a hardwood woodlot! completely between batches, since For US Grade B the bits left in the pan may darken Standards are the same as for AA, later batches of syrup. It may take as except color and clarity must be the many as 16 hours to make a syrup same or lighter than dark amber. “run” from the start—including col- lecting the sap. Sometimes weather Ungraded (unclassified) conditions make sap collection a No standards for color and clarity. “start and stop” process, so clean The other items (weight, brix, flavor, the boiling equipment between and damage) apply. batches—a chemical milkstone remover may be necessary to re- How is syrup packaged ally clean the pans—and rinse them for commercial sale? thoroughly. Collecting buckets, bags, Package the finished syrup in retail and tubing are usually disinfected containers when it is between 180° with a diluted bleach solution (1 part and 200° F. Use tin, hard plastic or commercial bleach to 9 parts water) glass for containers and use a vari- after they have been washed. ety of sizes—most people buy pints

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Issued 5-2010