Hay makes cheese holier…?

As if to prove that every story has a botanical link – if you look hard/close enough – how about this cheese-based revelation? For many years the formation of the holes that are found within certain Swiss cheeses – such as Emmental and Appenzeller – has been attributed solely to the CO₂-producing activities of bacteria (now known to be Propionibacterium freudenreichii).

However, recognising that those trademark holes became much smaller when the milk used in cheese’s manufacture was extracted using ‘modern’ methods, and no doubt concerned about the cheeses losing some of their distinctiveness (and USPs?), producers and retailers were understandably perplexed. What is it about modern milk extraction that affects the holes so markedly?

Apparently, it’s down to the fact that there’s no contact with the atmosphere when milk is removed directly from the cow’s teats into a collecting vessel in modern-day machine-milking *. Which contrasts markedly with the traditional hand-milking of cows wherein the milk is accumulated in an open-topped bucket. This allows for particles of hay to settle in the milk, and it’s these that provide the nucleation sites for the CO₂ bubbles that subsequently give rise to the holes.

And what is hay?

Hay is ‘grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing livestock such as cattle, horses, goats, and sheep’. So now it seems that the ‘holey of holies’ of cheese mysteries has been solved. Blessed indeed are the cheese-makers. What other cheese myths (botanically based ones, please!) are there to be busted?

* This study was undertaken by members of the Agroscope Institute for Food Sciences and the Swiss Federal Laboratories for Materials Science and Technology.