Place the coriander seeds in a dry frying pan and heat, stirring constantly until they become light brown. Remove them to a coffee grinder or pestle and mortar and crush the coriander seeds. Pass the crushed seeds through a sieve to remove the husks. 
Cut the meat into 50 mm cubes, and mix together with all ingredients except the vinegar and casings. Mince the meat using a grinder with a coarse blade. Sprinkle the vinegar over the minced meat mixture and mix lightly (If you work too much with the meat, it will lose the coarse consistency)
Prepare the casings and stuff the mixture loosely into them. 
Dip the sausages in a mixture of 4.5 litres boiling water and 350 ml vinegar, then hang them over wooden rods that are thick enough in diameter to prevent the inner surfaces of the sausage from touching. 
Dry the sausage in a cook draughty place for 24 hours, then remove the sausage and flatten by rolling across a cutting board, so that any pockets of air in the sausage or between the sausage and the casing are removed. (These air pockets can cause mould to set in when the sausage is drying). Put the sausage back over the wooden rods and continue to dry to your taste. This will normally take about 2 weeks.