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AIV fodder – the cream of the crop of Finnish inventions


June 11, 2019

Artturi Ilmari Virtanen devised how to significantly improve the quantity and quality of Finnish milk production. The AIV fodder he developed virtually saved the competitiveness of Finnish agriculture and also gained a worldwide reputation.

Artturi Ilmari Virtanen
, who ran the research laboratory of the Valio cooperative, was granted the 1945 Nobel Prize in Chemistry for developing the preservation method of AIV fodder, or soilage. Even though the dairy cattle certainly welcomed the invention, Virtanen’s primary goal was not the good taste of livestock feed, but improving the quantity and quality of milk production.

A. I. Virtanen (1895–1973) did a lot during his life. The studies he piloted generated significant innovations for developing the preservation and taste of dairy and food products. He also created a food supplement innovation important for public health. Virtanen held 25 Finnish patents and was a candidate for a Nobel Prize no less than 12 times after 1933.

What is the background of developing the AIV fodder, Kolster’s Patents Director Tapio Äkräs?

“In Finnish climate, the time cows spent out on pasture is short, and in times past, cows were fed with stored dry hay in the winter. However, the nutritional properties of dry fodder are weaker than those of fresh grass, which weakened milk production during the winter. Virtanen wanted to find a way to ensure that cows would milk well also in the winter without expensive industrial concentrated feeds.”

When was AIV fodder patented?

“In 1929, Virtanen applied for a patent for his FI15527 method in which acids or acidic salts in a liquid form were added to fresh, newly harvested fodder during the preservation phase so that the pH of the fodder pulp was between 3 and 4. The added AIV liquid  prevented the silage from spoiling while the nutritional value and aroma of the feed remained almost unchanged. AIV fodder was preserved in purpose-built green fodder towers or pits in the ground with wood interiors.”

How did the patent affect Finnish agriculture?

“At farms, the quantity and quality of the winter milk produced by cows increased significantly while the feed costs decreased. Valio sold AIV liquid  to dairy farms and obtained the milk produced through its cooperative dairies. Valio also launched a massive information and marketing campaign whereby the method was quickly introduced into wide use in Finland.

Investments were also made in the production of the AIV liquid. In May 1929, half a million kilos of hydrochloric acid were imported to Finland, making it possible to prepare AIV liquid  for the preservation of 60 million kilos of grass. In 1934, Valio delivered more than 17,000 bottles of the liquid. One bottle was enough to prepare about 6,000 kilos of feed, so the amount of preserved feed was about 102 million kilos.”

Did the invention spread abroad?

“The AIV preservation method was also patented internationally, which was not customary for Finnish inventions at the time. Sales of the AIV liquid were also expanded internationally. Valio registered the trademark T194100003 in 1941. The trademark is still in force.

Transporting acids as liquid solutions was difficult, so Virtanen developed the preparation method of AIV liquid further in the late 1930s so that AIV liquid could be prepared on site by mixing solid salts with water. Patents were also sought for these methods. In the 1950s, Virtanen applied for the patent FI28937 for the use of ammonium bisulphate in the preparation of AIV liquid.”

How is the invention doing now? 

“Inorganic acids have subsequently been replaced with formic acid, which is naturally occurring, rapidly and completely biodegradable acid. Following cooperation between Valio and Kemira, the manufacture of AIV liquid was transferred entirely to Kemira in the late 1980s.

Kemira sold its formic acid business to Taminco Corporation in 2014. In 2015, the US-owned Eastman Chemical Company acquired that business in its entirety and AIV preservatives became an important part of its product range. The company’s Finnish subsidiary, Taminco Finland Oy, is responsible for the formic acid business in Finland.

Nowadays, AIV fodder is usually stored in airtight plastic-wrapped round bales, which are a common sight in fields in Finland.”

What else did Virtanen invent?

“High-quality Finnish butter would not exist without the butter salt developed by Virtanen, which was granted the patent FI12587 in 1929. Butter made of sour cream became rancid quickly during storage, hampering its export abroad. Virtanen discovered that when the pH of butter rises above 6, no flavour defects occur. Virtanen thought to raise the pH of acidic close to neutral with buffer salts, and the taste remained the same. Butter salt was introduced at Valio’s dairies as early as in 1926, but its method of production was kept a secret for years. The good shelf life of butter was a significant advantage for Finnish exports at the time.

Butyric fermentation was also the worst problem in cheese making. In  the patents FI15877 and FI16415 Virtanen proposed to prevent it by adding a reagent that destroys the butyric acid bacteria in milk into the cheese milk.  Virtanen discovered that sufficient amounts of the reagent can be added without disturbing the hole formation or flavour of the cheese if strong propionic acid bacteria are also added to the cheese milk as pure cultures.

Virtanen also developed and patented natural food preservation methods and herbicides. The extensive adding of iodine into table salt was also started largely thanks to Virtanen’s research and insistence in order to beat the common national disease of the time: an enlarged thyroid gland, or goitre.”

To celebrate Kolster’s 145th jubilee year, we feature each month an interesting Finnish invention or patent.

The sauna stove – Evolution from a pile of rocks to a designer product
The history of the sauna stove dates back to the early 20th century, when Fredrik Terho patented his method for manufacturing sauna stoves made of iron. Over the past century, the product has evolved and far from a traditional barrel stove, modern saunas can boast a designer stove in the shape of an elf, for example.

Heteka - an iron bed that became a bestseller of its day
Who remembers the heteka? Quite a few of Finns, because two million sold units of this piece of furniture that grew into a hit product were produced.

Kolster’s first patent served the paper industry
The use of wood fibre as the raw material of paper was boosted when the first patent application filed through Kolster was accepted in 1874.



Tapio Äkräs
+358 50 5242406