Curing Royal Fern Shoots: Boiling, Drying and Rehydrating Step by Step

Why the shoots are processed, and why it is not optional

Freshly picked royal fern shoots are not food. They are harshly bitter and astringent, and the raw and lightly cooked shoots carry compounds that make them unsuitable to eat in that state. The full sequence, a hard boil followed by thorough drying and then rehydration, is what converts them into something edible. It is a processing requirement, not a matter of preference, and it applies to every shoot regardless of how young, small or tender it looks.

Understand what each stage does, because that is what stops people cutting corners. The boil draws out the bitter and astringent compounds into the water, which is then thrown away. The drying stage is not merely storage: the shoots are worked repeatedly while they dry, and that combination of dehydration and handling continues to break down the fiber and finishes what the boil started. The rehydration returns water to a shoot that is by then a completely different material from the one you cut.

A blanch alone is not the cure. A quick saute is not the cure. Freezing raw shoots is not the cure. If the shoots have not been boiled and then dried and then rehydrated, they are not ready, and there is no version of the process that skips a stage.

Never eat royal fern shoots raw, and never serve them after only a brief blanch or a light frying. If you are not going to complete the boil, dry and rehydrate sequence, do not pick them at all.

Stage one: boiling

Do this the same day you pick. The shoots should already be clean, with the woolly brown covering rubbed off and the cut ends trimmed. Work in batches small enough that the water stays at a rolling boil when the shoots go in.

1. Bring a large volume of water to a hard boil Use far more water than looks necessary, at least four times the volume of the shoots. A big volume keeps the temperature up when the cold shoots go in and gives the bitter compounds somewhere to go. A small pan of water saturates quickly and the cure is poorer.
2. Add the shoots and boil until they go limp and dark Drop the shoots in and keep the water boiling. They will turn from bright green to a duller olive and go completely limp. Depending on shoot thickness this takes three to eight minutes. A shoot that still has any spring left in the stem has not boiled long enough.
3. Drain and discard the water Pour the whole lot off. The water carries what you have just removed from the shoots, so it goes down the drain. Never reduce it, never reuse it for a second batch, and never keep it for anything else.
4. Rinse under cold running water Cool the shoots quickly and rinse them thoroughly. This stops the cooking and washes off the last of what the boil brought out of the tissue.
5. Squeeze out as much water as you can Take a handful at a time and press firmly. The drier the shoots go onto the drying rack, the faster the next stage runs and the less risk there is of mold setting in during a humid spell.

Stage two: drying, with repeated working

This is the stage people get wrong, because it is not passive. The shoots are not simply left out to dehydrate; they are rubbed and rolled between the hands at intervals while they dry. That working is what softens the fiber and gives you a shoot that rehydrates into something tender rather than a piece of string.

1. Spread the shoots in a single layer Lay them on a mesh rack, a woven tray, or anything with airflow underneath, in a warm, dry, breezy place out of heavy rain. Direct sun speeds it up considerably. A dehydrator on a low setting, around 120F (50C), works well if the weather is against you.
2. Rub and roll them by hand every hour or two Take handfuls and roll them briskly between your palms, then spread them out again. Do this repeatedly through the first day. The shoots will gradually go from limp to leathery, and each working session makes the next one easier.
3. Keep going over two or three days Bring them under cover overnight so they do not take up dew, then put them out and resume the rubbing in the morning. Expect two to three days of this in warm dry weather, longer in humid conditions.
4. Finish when they are dark, wiry and completely dry Properly cured shoots are dark brown to almost black, thin, wiry and hard, with no give at all when bent. They should snap or bend stiffly, never feel soft or cool in the middle. Any softness means residual moisture and that batch will mold in storage.
5. Store airtight, dark and dry Put the finished shoots into a sealed jar or a well-sealed bag once they are fully cold, and keep them somewhere dark and dry. Cured this way they keep for a year or more. Check the jar after a fortnight for any sign of condensation; if you find it, dry the batch again.

Stage three: rehydrating before use

Cured shoots are rock hard and have to be brought back with water and gentle heat before they are used. Do not attempt to shortcut this with a short soak in boiling water; the outside softens while the core stays hard and the result is unpleasant.

The standard method is a long soak followed by a gentle simmer and a further soak. Allow the best part of a day, and plan for it the day before you want to use them. Dried shoots swell to roughly four to five times their dry weight, so a small handful goes a long way.

Judge the result by feel rather than by the clock. A properly rehydrated shoot is soft and pliable all the way through, with no hard core when you cut across it, and it holds its shape rather than falling apart.

Judging the cure, and keeping records

Two failures are worth recognizing. An under-dried batch stays soft and springy, does not go properly dark, and grows mold in the jar within a few weeks. An over-boiled batch goes mushy in the pan and breaks up into fragments during the drying, which is unpleasant to work with and gives a poor result. Between them, err towards a longer dry and a shorter boil, and put the effort into the hand-working rather than into extra time in the water.

Record the picked weight, the weight after boiling and squeezing, and the final dry weight for each batch. Once you have those three numbers for a couple of seasons you can predict from a morning's picking exactly how much finished product you are going to end up with, which is what tells you whether the bed is actually large enough to be worth the work.

Note the drying conditions too, particularly how many days it took and whether the weather was humid. Batches that took an extra day are the ones to check first for storage problems, and after a few years the notes will tell you which part of your season reliably gives good drying weather.