Experiments | Washing¶
Expected Output: Documentation of the process, including step-by-step instructions and any open-source tools used to allow experimentation in similar settings.
This experiment focuses on using only the natural grease (lanolin) and potassium salts (suint) present in raw wool to create a mild alkaline washing bath through controlled fermentation—no external soap or chemicals are added.
The process allows recovery of valuable by-products, including up to 95% of wool grease (lanolin) and almost 100% of dust (soil and organic matter), which can be reused for fertilisers and other applications.
Compared to conventional wet scouring, suint fermentation achieves a 75% reduction in water use, effluent volume and chemical consumption.
Process details¶
| STEP | Details |
|---|---|
| Bath preparation | Submerge wool in water*. Temperature: 10°- 40°C (as warm as possible in winter) |
| Fermentation Phase | Monitor temperature and pH (pH target: 8–9, every 6-8h). Keep wool submerged for 1 week |
| Rinsing & Drying | Rinse gently with warm water and air-dry in a ventilated area. Lanolin remains in the wool as a soft protective wax and the dry fibers keep only their natural sheep scent**. |
| Final rinsing | (Recommended) Final wash post-dry. |
| (Extra) Lanolin Recovery | If the water is not reused for a second bath, let it sit overnight so the lanolin can float to the surface and collect it for future use. |
*Rainwater is the best to use or in the absence of rain, you could always use distilled water.
**The bacteria involved in this process are anaerobic, which means that once the fleece is out of the water and in an oxygen rich environment, they die and therefore the smell goes away.
| LIMITATION | Details |
|---|---|
| Seasonal Constraints | The process works best in spring and summer, when the temperature is warmer. |
| Wool Characteristics | Freshly shorn wool is most effective. This project uses wool shorn in October, which may affect fermentation. |
| Odor & Indoor Space | Microbial activity and lanolin may produce strong odors. Experiments are planned indoors due to winter conditions. |
| Regulatory & Hygiene Considerations | No official regulations exists.The substances are not hazardous but protective measures are used. |
Experiment in progress¶
Small batch test¶
Material: unwashed wool, water, stainless steel bain-marie, thermometer, pH strips, gloves (optional).
Quantity: 50 g of raw wool and 500 ml of water per batch, for three rustic wool colours: beige, dark, and mélange. Each batch was placed directly into stainless steel bain-marie containers.
Water-bath machine: Used on the first day to raise the water temperature. Heating was then gradually reduced and switched off, leaving the wool submerged.
Key observations
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Temperature: process started at 40°C. Containers were insulated with a wool blanket to limit heat loss and placed near a running air conditioner for 5 hours/day, allowing temperature to stabilize around 20°C.
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pH: initial pH 7 gradually increased to 8, within the target range.
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Odour: the characteristic wool odour progressively intensified, indicating ongoing biochemical activity.
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Monitoring is still in progress and wool will be removed and checked on Jan 27.
Experiment planned¶
Scale up to one fleece¶
Building on Experiment 1 (50 g batches), this experiment scales up suint fermentation to a full fleece, demonstrating feasibility for medium-scale lab-level batches, even during winter season.
One full fleece refers to the wool shorn from a single sheep in one shearing session, before any cleaning, sorting, or processing. Kg of one Thônes et Marthod fleece tbc in the lab.
Process key points
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Water: Prefer rainwater when available (collected locally in Lyon). Rease the bath from previous fermentation will speed up the process. It's not realistic to be able to save all of the water so it's fine to re-fill it with additional rain water as needed.
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Fleece preparation: Fully submerge the fleece to ensure complete coverage.
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Bath reuse: The fermentation bath from Experiment 1 can be reused up to three times, reducing treatment time from a week to a few days. Remaining water can be repurposed as fertiliser.
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Readiness: When the wool settles at the bottom, the fleece is ready.
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Temperature control: Passive insulation leverages wool’s thermal properties and stable indoor conditions; process remains viable down to 10 °C.
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Insulation inspiration: Norwegian haybox (Marmite norvégienne), a low-tech system using wool to trap air and retain heat. This serves as a reference for a potential open-source insulating system for winter fermentation.
The insulation system will be designed on Jan 29 during a dedicated session with Capucine. Experiment 2 will begin once the system is complete.
DIY Suint Machine ideas:
1. A tank (either HDPE or stainless steel with a LID)
2. a Cheesecloth around so that you can pull up that wool from the tank when its done
3. a thermostat, like the ones they use in fish tanks to control the temperature, so you need to buy one that is according to the litres your tank with be. This should also show what is the temperature continuously for monitoring.
4. An aquarium pump and a small recirculation pump.
Anastasia suggestion: "you would also find an old washing machine and take the perforated drum from inside."
Reference and Inspiration¶
- The Science behind the Suint Fermentation¶
Images: Martina Muroni unless otherwise stated.