It is named after Pál Kocsis, who bred the variety in Kecskemét in 1930 by crossing Pozsony Fehér and Csabagyöngye. There are many legends associated with the choice of name; however, it was probably named after the son of Pál Kócsis's friend József Irsai, Olivér, who was born in the same year as the variety.
It yields light, summery wines, while its soft acidity and aromatic nature mean that it is best characterised by its Muscat, grape blossom and grape aromatics. Dr Károly Bakonyi bred Cserszegi Fűszeres from the variety.
Literature also mentions the variety internationally, for example in Russia and in neighbouring countries. It is even cultivated by one producer in Switzerland, in Lucerne near Aargau, where it is quite simply called Muscat Oliver. It can be made as a monovarietal wine, in blends and even as a late-harvested wine.
It is found in many Hungarian wine regions and is cultivated on almost 2,000 hectares, with the highest percentages being found in the Balatonboglár and Pannonhalma wine districts. Quantitatively, the variety features the most prominently in the Mátra wine district with around 500 hectares. It thrives here on the volcanic, tuff soils, although it also feels at home on clay. Thanks to the cool climatic conditions, it also retains acidity well, yielding fresh, crisp, aromatic wines.
Wines made from Irsai should be consumed young to best preserve its crisp, fresh fruitiness and perfume. Dry wines best represent its aromatic character with its grape, grape blossom, Muscat and perfumed notes. It is characterised by light body and alcohol as well as fresh acidity complemented by elderflower and gooseberry. The perfumed notes already mentioned are generally the key characteristic of its wines. The variety yields attractive, fresh, youthful, approachable wines.