The Simple Things
Tapping a birch tree to harvest the sap isn’t difficult, it just requires some basic kit and a few ground rules. Firstly, you need to know what sort of tree you’re looking for: native birch or betula is common in the UK – there are many varieties, just take a good tree ID book if you’re not sure. The tree should have a trunk that’s at least 30cm round and make sure you ask permission from the landowner (check with your local council if you don’t know).
There are many different ways to collect the sap; you can use a simple wooden spout to go in the trunk, or a plastic bottle and some string. You’ll also need a hand drill and a wooden ‘bung’ (shop-bought or hand-crafted) to block the hole. You can also buy kits online, try touch-wood.co.uk.
A guide is to collect no more than 4 ltr per tree. If you want more, use several trees rather than draining one. Most importantly, stop the flow of sap once you’ve finished. This will keep your tree in tiptop health.
The best time to forage for birch sap depends on where you live, but a good yard stick is just before the birch leaf buds burst, usually in early spring.
Once the sap is rising, you only have 2–3 weeks to collect, so you need to be ready.
Birch sap needs to be kept in a cool place and will only last for around 2–3 days. If you’re short on time, simply freeze the sap in ice cube trays.