THE GARUM STORY
Garum at Baelo Claudia: How Fish Sauce Built a Roman Town
Baelo Claudia's fortune came from garum, fermented fish sauce made in shoreline vats and shipped across the empire — how it worked, and what to look for.
See Baelo Claudia tours on GetYourGuide ↗What garum actually was
Garum was a fermented fish sauce, made by packing fish — often small oily species alongside offal from larger catches — into salt and leaving the mixture to break down in the sun for weeks or months. The result was a strong, salty liquid used across the Roman world much the way fish sauce is used in parts of Southeast Asian cooking today: as a seasoning stirred into other dishes rather than eaten on its own. Quality varied hugely, and the best garum from named production centres carried real prestige and commanded high prices — a luxury condiment as much as a staple, and one of the main things a coastal town like Baelo Claudia could sell to the rest of the empire.
The tuna runs that fed it
Baelo Claudia's position on the Strait of Gibraltar put it directly on the migration route of Atlantic bluefin tuna, caught seasonally using almadraba net systems similar in principle to the traditional tuna traps still used along this coast today. Bone remains excavated at the site show tuna dominated the catch, alongside smaller fish such as sardines and anchovies. That seasonal abundance of large, oily fish — arriving predictably enough to plan a whole industry around — is what let a relatively small town build permanent stone processing infrastructure rather than just fishing for its own table.
Inside a salting factory
The stone-lined vats visible near the shoreline belonged to cetariae — dedicated fish-processing factories with separate areas for cleaning and cutting the catch, salting ponds for curing whole fillets, and vessels for the slower fermentation that produced garum itself. Archaeologists estimate the combined capacity of Baelo Claudia's vats at around 2,500 cubic metres, a scale that points to production well beyond local needs. This wasn't a cottage industry bolted onto a fishing village — it was purpose-built industrial infrastructure, and one of the best-preserved examples of this kind of Roman factory anywhere on the Mediterranean or Atlantic coast.
Where the sauce went
Garum and salted fish from coastal Baetica — the Roman province covering this part of Spain — were shipped out through ports like Baelo Claudia in sealed amphorae, and fragments of that trade turn up in archaeological digs as far away as Rome itself. For a town this size, that export trade was the real economic engine — more consistent income than tourism or agriculture could have offered on this stretch of exposed Atlantic coast. It's worth remembering, standing in the quiet forum today, that Baelo Claudia's Roman inhabitants would have thought of their town first as a fish-processing port, and only second as anything else.
What to look for at the vats
The salting works sit close to the ancient shoreline, within easy walking distance of the forum. Look for the regular grid of rectangular stone-lined pits of varying sizes — the larger ones were likely used for whole fish or tuna cuts, smaller ones for finer, longer-fermented garum. Channels and basins nearby handled the cleaning stage before curing began. None of this is dramatic in the way a temple or theatre is, and it's easy to walk straight past — but it's the clearest physical evidence of why this town existed at all, and worth slowing down for.
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