Carl Linnaeus, The Lapland Journey, translated by Peter Graves (Edinburgh: Lockharton Press, 1995), p. 193.
Northern Husbandry, 24/09/1732, ¶1125:
Unskimmed milk is often kept in casks for the winter as a sort of watery porridge. It becomes so sour that it cannot be eaten alone and it is therefore mixed together with fresh milk. If no milk is available, they add a 1/2 part of water and eat it with porridge. As a drink they prefer it to small beer.