In the saucepan heat the skimmed milk to 90C/195F and gently simmer keeping to this temperature for 10 minutes.
Remove from the heat and cool down to 39C/102F.
In the small bowl mix together the sour cream and milk and pour into the warmed skimmed milk. Stir thoroughly.
Add the rennet and stir in.
Cover with a clean tea cloth and allow the milk to cool down to room temperature. This needs to be done slowly so it will need to be in a fairly warm room.
Leave for 1 hour or until it reaches a consistency that when you use a knife to cut through the mixture it leaves an open split. This will depend on the temperature of your kitchen.
Place the colander over a large bowl and line with a double layer of muslin. Pour the skyr through the muslin to separate the curds from the whey.
Leave to drip through for a few hours, then gather up the muslin and squeeze any excess liquid remaining.
Place the skyr in a large bowl and keep the whey in a container in the fridge (it can be used for other recipes such as for scones).
Beat the skyr with the electric hand whisk to eradicate any lumps.
The skyr can be served with fruit and honey for breakfast or flavoured with garlic, salt and herbs for a savoury dip.
