Why retting is the first real test of your flax

Retting is controlled decomposition. You are encouraging bacteria and fungi to break down the pectin that glues the valuable bast fibres to the woody core inside the stem. Get it right, and the fibres slip free with a satisfying crack. Get it wrong, and you either fight a stem that refuses to separate or watch your fibres rot into weakness. For home growers, there are two practical routes: water retting and dew retting. Both work in the UK climate, but they suit different spaces, schedules and tolerances for smell.

Water retting: faster, cleaner fibres, stronger aromas

Water retting involves submerging bundles of flax stems in soft water. Rainwater, a clean stream, or a trough filled from a water butt are ideal. Avoid chlorinated tap water if you can; the chemicals slow the microbes you actually want. Tie stems into loose bundles about the thickness of your wrist and stand them upright or lay them flat in the water. Weigh them down with clean bricks or stones so they stay submerged.

Temperature matters. At 15–20°C, expect three to seven days. Warmer water speeds things up but raises the risk of over-retting and a stench that will make you unpopular at home. Check daily after the third day. You will see bubbles rising and the water turning cloudy. The stems become slimy. Pull out a test stem and bend it. When the woody core breaks with a snap and the fibres slide away from it, you are close. If the fibres feel mushy or break easily, you have gone too far. Drain the water, rinse the bundles, and dry them immediately.

Dew retting: slow, subtle, and kind to your water supply

Dew retting relies on nighttime moisture, morning dew, and airborne fungi. Spread your flax stems in a thin layer on grass or a clean tarpaulin. In the UK, late summer and early autumn are ideal: warm days, cool nights, and regular dew. Turn the stems every few days so they ret evenly. Rain is fine, but standing water is not.

Expect two to six weeks. The stems will turn from green to grey or silver. The fibres begin to separate naturally. Dew retting produces darker, slightly coarser fibres than water retting, but it uses almost no water and avoids the smell. It is also more forgiving if you cannot check daily. The main risk is uneven retting: patches may dry out too much or stay too wet. Keep the layer thin and turn it regularly.

Judging when stems are ready

The snap test is your best friend. Take a stem from the middle of a bundle and bend it sharply. If the woody core breaks cleanly and the fibres pull away in a ribbon, it is ready. If the stem just bends like a green stick, it needs more time. If the fibres tear or feel weak, it is over-retted. You can also rub a few stems between your palms: the core should shatter into small pieces (shives) while the fibres stay intact.

• Ready: core snaps, fibres slide free.
• Not ready: stem bends like a green stick.
• Over-retted: fibres feel weak and tear easily.

Check several stems from different parts of the bundle. Retting is rarely perfectly even. When most stems pass the snap test, stop. Do not wait for every single one. Over-retting weakens fibres permanently. Keep notes: date, method, water temperature or weather, and how many days it took. Your records will make next year easier.

Drying and storing your bundles

Once retted, dry the stems quickly. Hang bundles upside down in a sunny, airy place: a shed, a covered porch, or a drying rack. Turn them daily. They must be bone dry before storage, or mould will ruin your work. In damp UK weather, a fan or a dry room helps.

Store dried bundles in a dry, dark place. Paper sacks, cotton pillowcases, or breathable woven bags work well. Avoid plastic, which traps moisture. Label each bundle with the date, method, and any notes. Properly dried flax can keep for months, so you can break and scutch when you have time.

Preparing for breaking and scutching

When you are ready to process, take a bundle and break the woody core. A simple hand brake or a rolling pin on a board works for small quantities. You want to shatter the shives without damaging the fibres. Then scutch: scrape the broken shives away with a wooden knife or a dull blade. Finally, hackle the fibres through a comb to align them and remove short bits.

Work in dry conditions. Damp stems will not break cleanly. If your stems feel brittle, a light mist of water and a few hours in a sealed bag can help, but do not soak them. Take your time. Retting is the foundation; breaking and scutching reveal the quality you have grown.