If you’ve ever tapped a maple tree, surely you’ve tasted the fresh sap – unprocessed and unboiled – straight from the tree.
If you have never tapped a maple tree, perhaps you’ve got one of those nice neighbors who generously shares his or her bounty of maple sap. Or perhaps you’ve even purchased and consumed any of the various “maple waters” on the market today.
And if you have no idea what I’m talking about (…tree sap? What the heck is that?), allow me to put this into context.
In late winter/early spring, sap rises in certain trees (i.e. maples and walnuts) due to temperature fluctuations – notably, the freeze/thaw cycle. In other species (i.e. birches), sap flow is governed by root pressure that forms once soil temperatures reach approximately 50° Fahrenheit. This sap contains water and dissolved nutrients (i.e. sugars) that travel up towards the branches, feeding the developing leaves.
If you’re interested in learning which trees produce sap during this season, check out this recent video I filmed. In it, I discuss key identifying characteristics regarding 4 tappable trees, including 2 maples and 2 birches.
Let’s continue the story.
Whenever these trees are wounded during this particular season, sap will flow from inside the trees (sapwood) out through their wounds. Such is the case whenever we tap a tree by placing a hole into its bark. This sap, after collection and prolonged exposure to heat, can be eventually reduced into syrup.
But wait! Before we boil down our precious sap, transforming it into one of nature’s finest sweeteners, we can appreciate this subtly-sweet liquid for all that it is.
In other words, we can drink it. Call me old school, but I like to drink sap unprocessed, consuming whatever I can at the source and storing the rest in containers.
Now, I am familiar with the warning that one ought to boil the sap first, as there’s a possibility that it may harbor pathogenic organisms. If we’re managing a clean operation, however, I believe this fear isn’t always warranted. Still, use your best judgement.
Maple sap, depending on the species, contains varying levels of sugars – notably sucrose. Sap from the sugar maple (Acer saccharum), for example, is approximately 2% sugar.
For this reason, maple sap imparts a delicate, sweet taste to the palate, one that becomes extremely concentrated during the sap’s conversion into syrup. While I certainly enjoy maple sap for its delectable late-winter sweetness, I also appreciate its content of vitamins, minerals, enzymes, amino acids, polyphenols, and other health-promoting compounds.
You see, many people are aware that maple syrup confers numerous health benefits, typically dependent to some degree on color. In this article, I’d like to explore the health benefits associated with its often overlooked forebear, a mystifying substance that surely deserves more attention.
The benefits of maple sap
But first, a little history…
While maple syrup is certainly beloved by its largest producer, North America, perhaps no other country utilizes and appreciates maple sap more so than South Korea. It is here where villagers climb the hills every year to collect sap from a maple tree known as “Gorosoe” (Acer mono). This tradition spans almost an entire millennium. Traditionally, villagers would create V-shaped incisions into the trees and channel the sap away with bamboo leaves. Today, the operation is much more modernized, incorporating plastic spouts, tubing, and large holding tanks. Unlike in North America where most sap is turned into maple syrup, Koreans drink the sap with no further processing, or instead use it as cooking water.
Okay, now onto the benefits…
Maple sap improves osteoporosis-like symptoms
“Gorosoe” translates to “the tree that is good for the bones.” Sure, the name sounds promising, but is there any truth to it?
For starters, sap from Acer mono has been shown to contain an impressive mineral analysis, including 16 times the potassium, 37 times the calcium, and 3.9 times the magnesium contents of spring water. All 3 of these minerals are essential for optimal bone health.
To test the bone-supporting effects of maple sap on biological systems, researchers carried out experiments where they put mice on low-calcium diets and supplemented them with various concentrations of A. mono sap (1). Mice who were supplemented with both 50% and 100% maple sap concentrations retained normal serum calcium levels, compared to the lower serum calcium levels of mice fed spring water only and 25% maple sap.
Additionally, in the spring water-fed and 25% maple sap-fed groups, thigh bone density and length were significantly reduced, compared to the mice fed higher concentrations of maple sap. The researchers concluded that 50% sap solution could mitigate osteoporosis-like symptoms induced by a low-calcium diet, and they attributed its mechanism to calcium ion absorption.
Maple sap prevents gastric ulcer formation
Injury to the mucosal lining of the stomach can lead to stomach ulcers. Common causes include infection by the bacteria Helicobacter pylori, long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen, and excessive consumption of alcohol. If stomach ulcers are left untreated, they can eventually lead to gastric cancer.
Can something as simple (and tasty) as maple sap prevent these conditions from occurring? Researchers think so.
To test their hypothesis, researchers subjected mice to a procedure intended to cause stress-induced gastric lesions (2). Before the researchers carried out their experiments, however, the mice were pretreated with various supplements:
- One group received L-arginine, an amino acid known to prevent stress-induced gastric mucosal lesions.
- A second group received omeprazole, a prescription drug used to treat stomach ulcers.
- A third group received a freeze-dried powder of Acer mono sap.
- A fourth group (the placebo group) received a single saline administration.
Results were … well … quite impressive!
After being subjected to the stress experiments for 6 hours, the mice in the placebo group displayed abundant lesions, on average 1-2 mm in size. The mice who received L-arginine and omeprazole developed very few lesions. Remarkably, the mice who received maple sap prior to the stress experiments did not present any small or large sized corrosions.
In other words, not only was maple sap effective, it was more effective than L-arginine and omeprazole in protecting against gastric mucosal lesions. The mechanism behind maple sap’s protective effects seems to be related to its ability to significantly lower the mRNA expression of iNOS and nNOS, two enzymes that have been shown to play key roles in the formation of gastric lesions.
Researchers concluded that A. mono sap can be used as an ulcer remedy or for other preventive and nutraceutical purposes.
Maple sap lowers blood pressure
Like Acer mono, Acer okamotoanum is another species of maple found in Korea. Sap concentrations of calcium, potassium, and magnesium are 37, 20, and 3.9 times higher than the levels found in spring water. Just as calcium and potassium are two minerals that function in supporting optimal bone health, they also play a role in regulating blood pressure.
To test the blood pressure-lowering effects of A. okamotoanum sap, researchers fed hypertensive rats spring water supplemented with 25%, 50%, or 100% maple sap (3). Compared to the rats fed only commercial spring water, the rats supplemented with all concentrations of maple sap experienced reductions in blood pressure.
Researchers attributed the blood pressure-lowering effect of A. okamotoanum sap to its concentration of potassium ions. As an added benefit, body weight also decreased in the rats fed 50% and 100% maple sap concentrations.
Maple sap prevents hangovers
Originally, the title of this section was “Maple sap facilitates alcohol metabolism,” which is probably the more accurate phrasing of what I’m about to describe. But hey, sometimes you just gotta use sensationalism to capture your audience’s attention! Anyway…
As previously stated, A. okamotoanum sap contains various electrolytes (the dissolved mineral ions of calcium, magnesium, and potassium). Because alcohol consumption has a physiological effect on the absorption, elimination, and serum concentrations of electrolytes and minerals, researchers wanted to see what effect, if any, A. okamotoanum sap had on alcohol metabolism in rats.
Researchers administered concentrations of 25%, 50%, and 100% maple sap to rats, 30 minutes prior to receiving alcohol (4). Compared with the rats fed alcohol without any maple sap, the rats who were pretreated with maple sap demonstrated significant reductions 5 hours later in the blood concentrations of both alcohol and acetaldehyde – a toxic byproduct of alcohol metabolism.
Additionally, mRNA expression of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), two liver enzymes necessary for alcohol metabolism, was significantly increased in the rats pretreated with maple sap (increased is a good thing in this case). The results suggest that, at least in rats, consuming maple sap prior to ingesting alcohol can increase the rate at which alcohol is metabolized in the body. The researchers also concluded that maple sap may reduce oxidative stress associated with alcohol consumption.
Maple sap supports a healthy immune response
Whenever our bodies are exposed to pathogenic microbes, our immune systems heed the call to action. In particular, white blood cells known as neutrophils congregate at the site of infection and engulf (think swallow) the offending microbes. Once the pathogens are engulfed, enzymes within our bodies generate substances known as reactive oxygen species (ROS) that, through oxidation, eliminate the bad guys.
This latter process – of generating reactive oxygen species – is necessary in order to remove pathogens, but it can also inflict damage inside our bodies. Oxidation is an on-going process, but too much of it can be a bad thing. Regulation, therefore, is necessary in order to balance this delicate dance between eliminating pathogens while minimally damaging host tissue. Maple sap (A. okamotoanum) may indeed help.
To test this hypothesis, researchers treated mice, rats, and canines with a compound known to impair the immune system, then administered increasing concentrations of A. okamotoanum sap (5). Results showed that treatment with maple sap stimulated the activity of neutrophils (immune cells) in mice, rat and canines. Additionally, the sap enhanced the last step in this process – the elimination of microbes using ROS.
While this study was performed on animals, the researchers concluded that A. okamotoanum sap may have potential antimicrobial effects for patients with infection.
Maple sap contains antioxidants
As mentioned previously, oxidation is a natural process in the human body that, if left unchecked, can result in conditions such as atherosclerosis, diabetes, and Alzheimer’s disease (just to name a few). Antioxidants combat the process of oxidation, and can be produced internally as well as provided externally through the consumption of antioxidant-rich foods – for example, the sugar maple.
The sugar maple (Acer saccharum), a species native to North America, yields the highest volume and concentration of sap, making it a superior candidate for tapping. Its sugar content is approximately 2.0%.
Antioxidants within the sap of A. saccharum have the ability to scavenge the superoxide radical (6) – a potentially destructive molecule that has been implicated in numerous diseases, including diabetes and cardiovascular disease (7, 8).
Out of 10 compounds analyzed in sugar maple sap for their antioxidant effects, only 3 of these are found in maple syrup from the sugar maple. What this means is that several antioxidant compounds are seemingly lost in the transformation from sap into syrup. Perhaps this is one of many benefits to consuming maple sap in its fresh form.
Summary of health benefits: Sap from various maple trees has been shown to provide support for osteoporosis, prevent gastric ulcer formation, lower blood pressure, mitigate alcoholic hangovers, support a healthy immune system, and offer dietary antioxidants.
Now, I understand that most of the research cited in this article involved animals as test subjects. We – Homo sapiens – are animals, sure, though clearly not of the mouse, rat, nor dog type. Therefore, the academic in me will say that “though certainly promising, we cannot entirely extrapolate these findings to humans.” Very dry, I know. But really, researchers will claim that just because maple sap lowers blood pressure in rats doesn’t mean that it’ll do the same to you and me.
Also, I understand that most of the research on maple sap pertains to species of maple that aren’t native to the continent that produces the most maple syrup. Out of the 6 primary research articles I reviewed, only one used the species of maple nearest and dearest to most American tapping enthusiasts – the sugar maple, Acer saccharum. Therefore, we cannot definitively say that the sap from all species of maple will produce the exact same effects on biological systems.
However, the benefits outlined in this article should not be dismissed solely because animals were the test subjects, or because geographically-irrelevant tree species were used. That’s nonsense. There is no doubt that all maple sap, regardless of species, possesses an array of physiologically-active compounds including vitamins, minerals, polyphenols, and antioxidants that all confer important health benefits.
For example, sap from both the sugar and red maple (A. rubrum) has been shown to contain compounds that demonstrate anti-cancer effects (9). Sap from the sugar maple has also been shown to inhibit nitric oxide formation, a process implicated in numerous diseases (10).
If you ask me, I’d say that all maple sap possesses therapeutic potential, and I certainly wouldn’t limit the benefits to only a handful of species.
Additionally, I feel that not only can one acquire substantial benefits by consuming pure maple sap – straight from the tree, no further processing necessary – but I feel there’s another level of therapy to be gained through the actual process of harvesting the sap oneself. No middle man or woman… just you and the maple tree, joined together in communion by the elixir that imbues life to both it and you.
What do you think? Maple sap for the win? If you’ve never imbibed, I highly encourage you to try it. One sip could change your whole life (sorry, no research to back that up). 🙂
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Awesome, it’s getting close to that time of year isn’t it! I wonder if I could can it to preserve it and enjoy through the seasons?
It sure is getting close. Last year I began tapping the maples on March 9th, and it seems that I’ll be heading out around the same time this year, too. I’m not familiar with canning maple sap, but fermentation is definitely a good option. Kombuchas, home-made sodas, ales, and wines can all be bottled and preserved, and some commercial operations create these products. If you happen to successfully can your maple sap this year, please let me know how it turns out! Thanks for commenting.
I learned about drinking the sap from an old aboriginal couple..they told me that they freeze theirs, so that they can drink it all year round,,mostly in the winter tho..hope that helps!
I love making coffee and tea from the maple sap… no suger required!
I loved your article! I am new to drinking sap and am trying hard to find a way to store my sap to drink through out the year. have you heard of anyone pressure canning it?
Thank you for reading and commenting! Unfortunately, I don’t know of anyone pressure canning maple sap, though there does seem to be a lot of interest in doing that. If you enjoy the process of fermentation, look into kombucha, wine, ale, soda, etc. Fermentation seems like one of the best (and tastiest) ways to extend the sap’s shelf life. If you discover that pressure canning works, let me know… I’d love to hear about it! Thanks again for reaching out.
Just freezing maple sap in ice cube trays and transferring them into freezer containers.
water bath for ten minutes
I was just starting to boil my sap down when I stumbled upon this article. Now I pulled a few cups out just for sipping. Thanks!
Glad you enjoyed the sap as is! Until I acquire an evaporator, fresh sap – straight from the tree – is primarily how I consume it. Thanks for reading and commenting!
I recently did a workshop with my husband at Raccoon Creek Park near the ‘burgh and afterwards we thought (due to our inconsistent weather these past weeks) that our maple had quit for the season… but then yesterday it started dripping again and… it was true “tree friendship” I thought when taking a sip of the clear sap, straight from the maple! Everyone should experience this sap ceremony to welcome spring and to connect with the living tree world surrounding us. I later put some compost nearby as a thank you to our amazing maples… Thank you for sharing your wealth of knowledge and for drawing our attention to the more hidden side of nature that is untouched by human hands.
I find that drinking maple sap at room temperature is the best way to enjoy the subtle array of flavours that are present, leaving a most wonderful after taste that is somewhat akin to chocolate after taste. And what takes the cake it that it’s a healthy thing to drink.
I tripped over this and find the whole subject of tree tapping fascinating. I would like comments ( not rude please on tree listening) yes you saw it here first. It started with a joke to my Grandchildren, put your ear to certain trees on certain days, cool night bright morning and you can hear sap rising. Each tree has a different noise signature. I’m learning more about why but some sound like a train in the distance (Elm) some rumble and so on. Try it with you ear when nobody is looking or with the children with stethoscopes … Enjoy ! AJ
I would like to hear more of u
Just tapped my maple tree in my front yard for the first time today, I really enjoyed your article, thanks and God bless you
I just tapped a maple tree for the first time and boiled the sap 3 hours, strained it and drinking the lightly flavored “water” (sap) for the health benefits. How long will this last in the refrigerator, or should I plan to freeze some? Thanks!
Hi my name is abdallah I’m from chad northern Africa if anyone is interested I can export to them how much the want because I’m selling so if anyone who wants it u can contact me in my WhatsApp number +27670023991 thank u
How long do you have to Boil the maple water for it to be safe to drink and not make Syrup from it.
Please send all this information to me via an email so that I can share. I do tap a maple tree in my front yard and the sap is delicious. Jim. (firstname.lastname@example.org) Thanks.
Hello Adam, I just ran across this information while doing research on Maple bark. Do you know if maple bark has any medicinal value?
FILTERED MAPLE SAP: TASTE & NUTRITION
Maple syrup processing entails filtering at three or more stages between collecting maple sap and filling a container with maple sugar and sealing it.
If some of the minerals and other nutrients are not filtered out of the sap, the resulting maple sugar can appear more or less cloudy, which apparently does not fit the desired profile of Four Standard Colors (Golden, Amber, Dark, Very Dark), all of which are ideally clear and transparent when exposed to light.
Pure maple syrup is effectively denatured maple sap. The taste and nutritional value of minimally filtered, cloudy, pure maple sap can be a mark of expert artisan craft that is preferred by some individuals, just as artisan bread, beer, wine and cheese are preferred.
It would be interesting to know your opinion on “cloudy” pure maple syrup.