Birch Sap

Two weeks in March. That’s all that’s promised for the birch sap harvesting time frame. It’s been on the to-do list for some time, and with the persistent warm temperatures and lack of frosts there could be only a few viable days left in which to gather it. Foraging a wild delicacy with such a short season is both exciting and frustrating, as there’s little time to perfect the technique, and the chances of failure are pretty great. More as a record of practice than anything, this is a detailed account of the process.

The first point of discussion when deciding which approach to take when tapping a birch is whether to pierce or to drill. Video-making bushcraft enthusiasts abroad on the internet talk about feeling the need to enjoy the ancient springtime ritual of tasting the lifeblood of the birch, regurgitating the traditional methods, only to whip out a cordless drill and get straight to work, jerry-cans and plastic tubing supplied. Those with no sense of their own ridiculousness will at this point be telling us that our ancestors could have done the same with specialized stone tools, in the same breath ratcheting the Black n Decker into high-gear.

It will no doubt be clear that I am pursuing the simple method.  I can’t see the point of hypothesizing stone-age birch tapping techniques without attempting them yourself, which neither the bushcraft people nor I have intention of doing. Instead I have chosen to collect sap with the most regular, most apparent and simple tools – a knife and a bottle of some kind. Pretensions of mesolithic authenticity can go and hang on their peg, so long as the bushcrafters are busy with power tools. If I knew someone with a hand drill, I might have used that. To be honest I doubt it.

The second point of discussion leads immediately from the first, that being, volume. To do anything on a grand scale with birch sap, the method I’m using is of course useless. This is exactly why it should be done in this way, working on the principle that if a little is precious, take precious little. This may be turning logic on its head, but turning your local bit of birch grove into the sap equivalent of a Saudi oil field doesn’t feel in keeping with the spirit of the venture. In this case, a ‘significant amount’ should have emphasis on the adjective, not the noun. If not, there’s no essence to the ‘ritual’ itself whatsoever; it’s just a novel resource.

What I want to experience is the sensation of the sap rising, lying in bed at night half-dreaming of its slow drip; while it is viable I want to be aware of it throughout the day, collecting in the bottle at a rate of about one droplet every few seconds. A cupful of this gained in situ would require many a man to stretch the limits of his patience, though I wonder what freedom of thought it would give him to do nothing other than sit quietly by his tree and wait.

So, enough of the philosophical aspect for now. The third point is that location will determine much about the method of practice you choose. Landed gentry can feel free to rig up demi-johns and elegantly carved and painted taps for their trees, but those tapping trees on public land will have to do things a little more clandestinely. Conspicuous set-ups will be at the mercy of any other people sharing the space, and a curious nudge with a wellington boot or more intentional sabotage is likely to lead to disappointment when checking on your nectar. Unlike the landed gentry, there’s little you can do about it, except spreading the risk over multiple spots.

Tapping the sap.

The method of knife-and-bottle sap vampirism runs as follows (for use in a semi-urban environment).

  • Go for a walk with a bottle (glass if you have it, plastic if not) and a sharp pen-knife with a locking blade, and if you can stretch to it, a thin skewer-like object (if not, a long sturdy thorn will do).
  • Find some sheltered birches which are budding, and whose bark is beginning to peel. Note the site, and go and find an ash tree, or even better saplings rising from the ground. Cut a centimetre-thick length and check for the spongy core. If you’re doing multiple set-ups, take a long piece.
  • Return to your sheltered birches, and find one with at least the diameter of your fingers making a circle (index finger to index finger, thumb to thumb). A kinked or sloping trunk over loamy soil is ideal.
  • Position your bottle at the base of the tree, as snug as possible against the trunk. Ideally, you want the tap resting on the lip of the bottle for stability, but get it as close as possible. In loamy soil, bury the base of the bottle and pack earth around it. On harder ground, box the bottle in with stones, bricks, or rubble. Staking around the bottle is also an option. Though securing the bottle to the branch would be ideal, location dictates tactics; city folk are just too curious in tampering with obvious set-ups. Camouflage the bottle with dead leaves and built-up soil (or, in other cases, litter). If you’re worried about flies getting in the sap, stuff or cover the neck with suitable material. Where I am, it’s too cold to worry much about them in March.
  • Remove the bark from your piece of ash-wood. Shave in half way along, and taper the end down flat like a woodwind reed. The other end is your bung end, and this you can hollow with wire or with a long thorn or spine. Taper down but don’t expose the channel where the core used to be. The whole piece should be less than a centimetrre in diameter. Keep it clean as to protect the tree (and the sap).
  • Measure with your eye the angle and length the tap will need to be, bearing in mind the little gravity needed to maintain the flow. Now you can adjust your tap if it’s a little too long. Find a smooth, non-gnarled point on the birch bark, and pierce it laterally with the tip of your knife about two centimetres deep. The tighter the better, as sap will leak down the sides of long cuts, and not gather in the tap’s channel. Make another fine cut slightly below this, and remove the sliver of cork. The sap should begin to flow almost immediately.
  • Slide in your tap gently (to avoid breaking it) making sure it is tight, and take care of any fine-tuning (angle, length, bottle’s stability) unhurried. Rushing it will mean you return to a failed set-up, the tap having fallen out, the bottle having shifted out of place, or both. Wait for ten drops or more, if you can afford to. Return to check on the set-up once more before leaving it overnight.
  • After taking the sap, tend to the tree. The small slits made by this method should heal in a few hours. If you’ve had to work a little bit harder to fit the tap, and have made a bigger incision, melt a little wax and apply to the wound. Chewing gum works just as well if there is a real indentation.

The ash-wood tap in action.

This is the method, in my opinion no better or no worse, than someone with practical and technical abilities approaching my own (i.e. as good as none) might manage. Drawbacks are several; the need to keep the bottle out of sight means less choice of good healthy trees, and therefore also less flow, the incision into the cork layer being minimal as it is. Another approach would be to set up ‘leeches’ – bottles fastened unobtrusively higher up on the trunk but perhaps on the tree’s far side if it can be said to have one (path edges, lining open spaces). The lack of tubing or other pipe material means that set-ups can be sent off-line very easily, potentially even in a strong wind, the branch moving, the bottle staying put. Also, the small, chip-like taps obviously don’t deliver the volume of a bung-like spout hammered tightly into the tree, but that’s been explained already.

The best working set-ups for me were those where I’d managed to get the ash-wood tap really clean and smooth inside. I get the feeling that when there’s still leftover bits of core and dust in the channel, the flow can easily get blocked. This sometimes doesn’t matter, as the sap should flow on the underside of the tap too, but it increases the chance of the sap running out down the bark from the wound where there’s less resistance. I’ve gotten two varieties of sap – a clear, slightly viscous type, and a cloudy, honey-coloured type from a different spot. They both taste the same pure, though the cloudy type is no good for what I’ll be writing about next, and that’s what to do with the sap.


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