What is Fernet?

By far the most famous type of fernet is Fernet-Branca, but there are other fernets on the market. So what is fernet, generally speaking? 

(Thanks to commenter Scott who wrote in on the "Shhh It's a Secret" seminar at Tales of the Cocktail write-up for asking the question that I never thought to ask.) 

I asked John Troia, co-founder of Tempus Fugit Spirits. They have a fernet coming out, Angelico Fernet. Here's what he says.

I’m sure there may be varying degrees of opinion, but we feel that the following is reasonably consistent with our research and that of others:

Although categorized under Italian Amari (Bitters), Fernet is its own bitter category and is most often listed underElixir/Elisir in Italian liquor manuals, when not simply called ‘Fernet’.The extremely bitter (amarissimo is an apt description) concoction has its origins most often attributed to Bernadino Branca, who commercialized it in 1845, but conflicting data conjectures its creator(s)as : a mythical doctor/collaborator of Branca from Sweden named Fernet (possibly as an off-shoot of the older and better tasting ‘Swedish Bitters’); Maria Scalia, the wife of Bernadino Branca who was a master herbalist and self-taught doctor; a monk named Frate Angelico Fernet  who may have been responsible as the origin of many herbaltonics and elixirs (Fernet being a historical French Burgundy  surname - pronounced Fair-Nay- and which underwent many spelling transformations); and a modern Italian liquorist text-book reference to it having originated somewhere in Hungary. 

Fernet was most likely created to counteract the effects of Cholera and Malaria, but went on to be used for everything from a laxative to hangover cure. Today, as in the past, there are many Fernet producers (with the largest making so much of the world’s production that some actually believe Fernet is a brand-name), but mostly made in tiny quantities for local rural Italian consumption. The various known recipes most typically share ingredients such as Aloe, Saffron, Quinquina, Gentian, Anise, Angelica, Mint and the odd Larch/White Agaric, a type of tree-bark loving mushroom (once also known as Spunk) rarely used or even found commercially outside of Italy. This latter ingredient (along with Saffron) seems to define and create the backbone of the best Fernets; Agarico mondo has an odd, bitter taste that becomes lightly mentholated on the mid-palate and was used to treat night-sweats.

According to Abruzzo’s local doctor, pharmacist, wine-maker, distiller and bitter-maker Marchese Dottore Egidio Niccolo Antonio d'Alesasndro di Trasmondi, the best Fernets have little or no sugar in them as it impairs digestion.

Thanks John - any questions?