In Finland's early years of independence, milk production had risen, and this had led to an increase in butter exports. However, the quality of the butter was often so poor when it reached its destination that it could no longer be used as a foodstuff. Virtanen therefore set to work energetically on the problem of butter quality. He noticed that Finnish butter, with its fair degree of acidity, readily acquired taste defects. When the pH of the butter was raised to 6.5-7 by using a salt buffer, these defects disappeared. AIV butter salt was patented in Finland, and its constituents remained unknown to competitors for a long time. There was thus a brisk demand for Finnish export butter on the British market. It was not, for example, until some ten years after Virtanen's discovery that Swedish specialists unravelled the secret of AIV butter. - http://www.kansallisbiografia.fi/english/?id=4753