Rot around the clock

January 7, 2012

Just before midnight on New Year’s Eve, celebrating with friends at The French Table, I found myself tipsily comparing flavours and fragrances of some wonderfully delicious sweet wines. And in particular I was looking out for the distinctive concentration and complexity characteristic of noble rot, the benevolent form of botrytis cinerea.Staring into the wine

The recorded history of deliberate use of the botrytis fungus in winemaking dates back to 16th century Hungary, but I think it’s highly likely that the technique has been known much longer, especially as sweetness in wine has historically been valued much more highly than it generally is today. I’m sure the Romans would have loved the idea but I haven’t found any evidence they discovered it – probably just because the Mediterranean climate is unsuitable.

The rot spread from Hungary to Germany and France, and for centuries has been an established part of winemaking in all three countries, producing highly prized intensely sweet wines – Tokaji Aszú; the sweet wines of Bordeaux, notably Sauternes, and the Beerenauslese and Trockenbeerenauslese rieslings of Germany. It’s now also made in several other countries including Australia, the USA and South Africa, I believe using introduced spores.Sweet wine collection

As an aside, I strongly advocate trying some of these wines if you haven’t already!

Botrytis cinerea is a fungus that affects many plant species. I don’t believe its effects are considered beneficial in any of the others – but has this been tested? Strawberry Sauternes anyone? Rhubarb Aszú? –  and it can be disastrous for grapes just as easily as delicious, if the climate isn’t just right in a particular year.

It requires a very particular damp temperate climate with a pattern of misty mornings and sunny afternoons that can arise around certain fortunate river valleys. If the weather stays wet too long into the autumn, the malevolent form of botrytis – grey rot – can form and destroy the whole crop. As with so many things, perfection is close to disaster.Botrytis strawberry

There are of course alternative techniques for making intensely sweet wines, with freezing on the vine (ice wine) being another approach that is also highly prized, risky and laborious.

This set me thinking more generally about what types of food and drink tend to become established as delicacies, and why. In many cases it’s simply rarity – including difficulty of extraction – caviar, saffron and truffles are examples. Some favourites may originate with a fleeting fashion such as a monarch’s preference.

Sensory preferences can rarely be explained in rational terms, and structuralists would have plenty to say about the need for a hierarchy of qualities to give meaning within a value system. We have a social need for some things to be declared exceptionally fine and exceptionally base. It helps make sense of everything between. And psychologically it makes sense to me that we are drawn to declare things supreme in some rather irrational, but potent, ways – proximity to danger (e.g. fugu), powerful physically challenging sensations (e.g. durian), and proximity to putrefaction, whether caused by fungus, bacteria or other natural processes, such as botrytis in wine.Choosing durian in Bali

I strongly suspect that in cultures all around the world there are examples of this botrytic knife-edge between the exquisite and rank, mostly originating in historical accident, but now elevated to the state of expensive delicacy. I’ve listed a few here, and I’d love to hear about any more!


Slimy, pungent, intensely flavoured fermented soy beans usually eaten with rice. Natto

Shiokara Japan

Salty fermented seafood viscera made into a thick lumpy paste.

Hundred-year eggsChina

Eggs preserved in an alkaline mix of clay, ash, salt and lime for several months, developing deep green and brown colouration and a cocktail of new flavours and odours.

Blue cheese is another obvious European example, and it divides opinion in my household every Christmas. Veining with penecillium mould is for me a visual, taste and aromatic treat, though it does require care in matching with other foods and drinks. Both fungus and bacterial growth contribute to the complexity of cheeses like Stilton and Roquefort. In general dairy products seem prone to natural processes that can invite differences of interpretation. For example, I’ve always considered that an old yoghurt simply morphs into a different type of yoghurt (experiments were carried out in undergraduate days), but not all agree.

I’m reasonably adventurous with cheeses, but there are a few notable specialities that I haven’t yet tried:

Casu MarzuSardinia

A traditional sheep’s milk cheese carefully decomposed using fly larvae.


A zesty aged quark with a rind fermented by small tyrophagus casei mites.Cheese mite

Garum, the classic flavour of the Mediterranean world in ancient times, is an interesting example. A nutritious salty sauce made from intestines and other parts of fish, it was widely produced in many varieties from a basic table condiment to elevated gourmet forms for Roman haute cuisine, and also used in cosmetics.

Like several of the foods mentioned here, fermentation is the key, with processing by salt and enzymes preventing other forms of spoliation that would be harmful. It was essential for the raw ingredients to be extremely fresh, hence facilities being located very near the sea. We know perfectly well how to make garum because ancient writers explained it, and quite a few people have tried. See links here, here and here.

Finally a few more mostly fishy things to finish:


King salmon and other fish heads allowed to decompose to a carefully controlled degree – similar processes are applied to many foods in the far north.


A form of fermented herring made with subtle bacterial processes to maintain nutritional value, developed as an alternative to salting. There is said to be a Surströmming museum at Skeppsmalen on the Gulf of Bothnia (no website).


Greenland shark hung for many months to allow bacteria to remove dangerous toxins, but leaving a strong ammonia odour. I did wonder if this might appear in the lyrics of any Sigur Rós songs but it seems to inhabit the wrong aesthetic universe. There is however a fun track from Simian Mobile Disco on their intriguing album Delicacies.

I’m conscious that this topic leads neatly onto thinking about foods and drinks believed to have spiritual qualities, including perhaps aphrodisiacs. But that calls for at least one more blogpost.