Date of the eruption, yet more proof!

Here is something that interests me a lot, not least because the debate has been raging for over 250 years: the date of the eruption. Just two years ago, Greta Stefani was arguing for a November date based on the discovery of a coin that couldn't have been minted before September AD 79. Now Anna Maria Ciarallo is arguing once more for an August date. This article appeared recently in The Times (Oct. 29, 2008):

Stinking fish confirms date of Pompeii's destruction
Analysis of the town’s last batch of garum, a pungent, fish-based seasoning

The remains of rotten fish entrails have helped to establish the precise date of Pompeii’s destruction, confirming the accounts of Roman authors, Italian archaeologists report. They have analysed the town’s last batch of garum, a pungent, fish-based seasoning, frozen in time by the catastrophic eruption that covered Pompeii and nearby towns with nine to twenty feet of hot ash and pumice.
The desiccated remains were found at the bottom of seven jars and revealed that the last Pompeian garum was made entirely with bogue, a Mediterranean fish species. The vessels were unearthed several years ago in the house of Aulus Umbricius Scaurus, Pompeii’s most famous garum producer.
“Analysis of their contents confirmed that Mount Vesuvius is likely to have erupted on August 24 in AD79, as reported by Pliny the Younger in his account on the eruption,” Annamaria Ciarallo, director of the Pompeii applied research laboratory, told journalists.
Garum was made by fermenting fish in saltwater and had a sweet and sour taste. It was used on almost every dish and was often a substitute for expensive salt.
Producing garum was relatively simple. A layer of fish entrails was placed on a bed of dried, aromatic herbs such as coriander, fennel, celery, mint and oregano.
This was covered by a layer of salt about two fingers deep and the sequence of herbs, fish and salt was repeated until the container was filled. The concoction was left in the sun for a week or so, and the sauce was mixed daily for about 20 days.
The end result was widely available at open-air trattorias, thermopolia, where Pompeian “fast food” was served. The sunken jars on the counter contained spiced wine, and stews of meat or lentils, as well as garum.
“Pompeii’s last batch of garum was made with bogue, a fish that was cheap and easy to find on the market in summer months. People living in this region still make a modern version of garum, colatura di alici (anchovy juice), in July when this fish abounds on the markets,” Dr Ciarallo said.
“Since bogue abounded in July and early August and recipes recommend leaving the fish to macerate for no longer than a month, we can say that the eruption occurred in late August or early September, a date which is compatible with Pliny’s account.” The date of the eruption on August 24 is confirmed by biological data, Dr Ciarallo said. “The pollen found in Pompeii belongs to some 350 summer species. This is more evidence in favour of Pliny’s account.”
Doubts about the date of the eruption emerged a few years ago when archaeologists discovered a coin that seemed to refer to the 15th imperiatorial acclamation of Titus. This is believed to have occurred on September 7, AD79. “Unfortunately, that coin is hardly readable. However, it is not so important whether the eruption occurred in August or in October,” Teresa Giove, of the Naples archaeological museum, said.

Teresa Giove may have a point!
Thanks to Lawrence Keppie for drawing my attention to this article.