- Boil water for 1 hour to annihilate any potential pathogens present in river water. Extra half liter for tea absorption, splash and spillage and evaporation during boil.
- Allow temperature to drop to 92 Celsius.
- add Tea and Achillea millefolium - I used a large hop filter from a brew kettle, if added loose you will need a large stainless steel strainer to filter.
- Steep for 12 minutes
- Remove tea and yarrow.
- Drop temperature to ~30C using a stainless steel coil immersion chiller.
- Add citric acid or lemon juice.
- Transfer to a sanitised 18L Cornelius keg
- Drop temperature as low as possible (immerse and leave keg in river?)
- Connect to a CO2 cylinder, purge air and force carbonate at 40 PSI / 3 Bar for 24 hours agitating regularly to assist CO2 absorption. If working on a smaller scale you could use a SodaStream machine to carbonate.
- Connect to chiller / dispensing tap and serve chilled.