Suint Fermentation method

Suint fermentation is a pre-industrial wool washing method based on the natural properties of raw fleece. It uses the suint (dried sheep sweat rich in potassium salts) together with naturally occurring microorganisms to create a mild alkaline washing bath without adding external detergents.
When raw wool is submerged in water, the suint dissolves and through fermentation, develops soap-like properties that help break down dirt and impurities. At the same time, anaerobic bacteria contribute to decomposing organic matter present in the fleece.
The result is a low-energy, water-efficient cleaning process, avoids the use of chemicals, and allows the bath to be reused multiple times and eventually repurposed as a natural fertilizer.

Minimum conditions for the process to work


- Water (full immersion): unwashed wool must remain fully submerged in water (rainwater preferred) to activate the process.

- Temperature: warm conditions are fundamental, ideally between 20°C and 40°C. For this reason, suint fermentation is typically run in spring–summer.

- Alkaline environment (pH 8–9): as fermentation progresses, the bath becomes slightly alkaline, enabling the detergent effect of suint.

- Strong odor: fermentation produces a noticeable, often unpleasant smell due to bacterial activity.

- Time: process typically requires ~7 days for the first bath activation. The same water can be reused for multiple cycles, reducing processing time to 3–4 days.

- Low oxygen conditions: anaerobic bacteria drive the process while the wool is submerged; their activity decreases when exposed to air.

- No agitation: keep the bath undisturbed to prevent felting, especially with coarse wool.