It was the strangest tasting I've ever attended. On at least two occasions, as the liquid hit the tongue, faces screwed up in horror, and exclamations of “@#%&!” escaped from assaulted mouths.

Yet no simple wine tasting would have thrown up flavour descriptions as disparate as "cardamom and orange peel", "dusty earthy", "dry mint lolly" and "clove cigarette."

What we were tasting was a range of that class of alcoholic drinks known collectively as "digestives".

And, in the absence of any satisfactory definition – Larousse offers only "a liqueur or spirit that may be taken after a meal more for the pleasure of drinking it than any digestive action" – it was decided that it would include any drink other than wine that included in its ingredients herbs, or (in one instance) resin, or some sort of vegetable additive.

And it had to be bitter. Now of the four major tastes (the others being salt, sweet and sour), bitter is perhaps the least enjoyed, sought after or cultivated by either cooks or beverage makers. Yet bitter is a flavour that I have always sought and enjoyed.

Lots of foods have it. There's a bitter edge in the best olives; radicchio gives an agreeably bitter note to a salad and jousts well with the sweeter more peppery rocket; it's one of the components in the flavour spectrum of good coffee; paprika at its freshest and sweetest also has a bitter note; the Chinese bitter melon and the Italian rape both counterpoint perfectly the sweetness of pork; and so curiously bitter is the artichoke that it is almost impossible to match wine with it (although I'm told that Pinot Grigio can do the trick).

I first tasted Fernet Branca in my twenties when my drinking habits were somewhat less temperate. It was recommended – indeed advertised in those politically incorrect days – as a hangover cure. "If you can keep this down, son, you can keep anything down." The older experienced bloke who told me this handed me a small glass of a viscous liquid the colour of Vegemite. I tossed it back, gagged, went “@#%&!”, almost gagged – some things never change – and immediately felt better.

Then, in Rome, a friend introduced me to Averna Amaro (“amaro” means bitter in Italian), which, she told me, was the fashionable drink that year. I loved it, on ice with a twist of lemon rind, before, rather than after, a meal when it seemed to stimulate the appetite. The next year, Cynar, the artichoke digestive, was all the rage. Although a pleasant drink, it didn't grab me as much.

The other thing that unites this eclectic bunch of bevvies is their colourful histories, most of which you can read about on their websites. Averna being fairly typical, with the story of Salvatore Averna who was born in the city of Caltanissetta in Sicily in 1802. Salvatore became a benefactor to the convent attached to the Abbey of S. Spirito (good name!), where friars produced a herbal elixir to an ancient secret, this recipe never ever leaving the walls of the abbey, until, in 1854, they handed it over to good old Salvatore.

Fernet Branca is made from over forty herbs, some of which are chamomile, cinchona (the source of quinine), gentian, peppermint, saffron, rue and wormwood (also found in absinthe). As the recipe is still closely guarded by the family, you'll have to be content with that lot.

But to return to the tasting – details of which follow – the other extraordinary thing about this lot was the way in which, once the initial shock of the new (flavours and assault of the bitter) had passed, how the eyes brightened and interest was pricked. I'd thoroughly recommend a safari into the largely uncharted (at least in this country) land of the digestives for anyone with an open mind – and a receptive palate.

The tasting

An informal but informed tasting, taking in 10 digestives all available with a little hunting (the % figure after the name is alcohol by volume).

1. Campari: Italian, 25%
Light, herbaceous “pink” nose and colour, with orange notes, nice quinine balance, and orange sweetness on the palate.

2. Jagermeister: German, 35%
Chocolaty brown colour, minty toothpasty aroma, more acid than bitter on the palate, mild liquorice flavours.

3. Gammel Dansk: Danish, 38%
Brown colour, orange peel and cardamom on nose, hints of clove, distinctly bitter medicinal flavours, lower sugar content highlighting the bitter/spicy character. A good system cleaner, much favoured by the Danes for breakfast.

4. Amaro Lucano: Italian, 30%
Reddy brown colour (similar to Gammel Dansk), cardamom spice aroma but not as pronounced, a whisper of lemon rind, and a bitter cherry-like character. Thick mouthfeel from high sugar levels. Pretty label.

5. Averna Amaro Siciliano: Italian, 32%
Dark coffee-like colour, cough syrup nose with orange/spice overtones, hotter than the Lucano, big, rich coffee flavours and high sugar level mask the bitterness.

6. Fernet Branca: Italian, 40%
Regulation dark brown with Pine O Cleen-like antiseptic aromas and mint lifted by the high alcohol. Huge bitter bite in the mouth (low sugar), liquorice at the end. A lasting numbness in the mouth, from the eugenol from the cloves.

7. Underberg: Swiss, 44%
Dark, complex, dry and dusty spicy aromas, cardamom, five spice. Flavour distinctly clove, even clove cigarette, mouth numbingly bitter, much less sugar, but not the heat associated with high alcohol lift. Much liked.

8. Mastika: Greek (Chios), 30%
Not strictly a digestive, but bitter, vegetal and delicious, so we bunged it in. Clear liquid, distinctly damp earth mushroomy nose, quite thick and sweet but sugar content trails off to a fine, dusty, earthy, almost tannic finish. Pleasing and intriguing, with good complex length. Hit of the day.

9. Centerba 72: Italian (Abruzzo), 70%
Lurid GI lime cordial/nail polish remover colour. Crass, coarse alcohol assault on the mouth, incredibly hot and peppery. After the slap, some sugar comes through but you're too busy trying to regain some feeling in the gums. Horrid.

10. Branca Menta: Italian, 40%
Cheap green mouthwash/toothpaste aromas. High sugar content therefore less bitter finish, but unpleasant green mouthwash lingering on the palate.