Yarrowia
Also known as Yarrowia lipolytica
The most vigorously fat- and protein-splitting of the cured-meat yeasts, a powerful builder of flavour, valued in measure and a nuisance in excess.
Yarrowia lipolytica takes its species name from exactly what it does: lipolytic, fat-splitting. The genus honours the British yeast taxonomist David Yarrow. It is a true yeast, salt- and cold-tolerant like the rest of the curing flora, and it stands out among them for the sheer strength of its enzymes.
Where Debaryomyces works gently, Yarrowia works hard. It is the most powerfully lipolytic and proteolytic of the common cured-meat yeasts, tearing into fats and proteins to liberate a flood of free fatty acids and amino acids, the raw material of aroma. In measure this builds a deep, complex, aged flavour; in excess, or in the wrong balance, that same vigour can tip a product towards soapy, rancid or overripe notes, so it is a yeast to harness rather than to let run.
Long present as part of the wild surface and interior flora, Yarrowia has drawn growing interest as a deliberate ripening culture, and beyond charcuterie it is a celebrated industrial workhorse, engineered to make everything from flavour compounds to fats and oils. In the curing house a curesmith may rely on its native presence or inoculate a selected strain for flavour, giving it the cool, salty conditions it shares with the other yeasts, and watching that its enzymatic power stays in balance with the gentler flora.