Why are some amphoras pointed on the bottom?

Question

Most liquid containers, such as barrels, are flat in the bottom and thus easy to store and pile up.

However, some ancient amphoras were pointwise in the bottom arguably making them less easy to store. Why was that so?

(example taken from wikipedia)

Answer 1

From the same wiki article:

The amphora complements the large storage container, the pithos, which makes available capacities between one-half and two and one-half tons. In contrast, the amphora holds under a half-ton, typically less than 100 pounds. The bodies of the two types have similar shapes. Where the pithos may have multiple small loops or lugs for fastening a rope harness, the amphora has two expansive handles joining the shoulder of the body and a long neck. The necks of pithoi are wide for scooping or bucket access. The necks of amphorae are narrow for pouring by a person holding it by the bottom and a handle. Some variants exist. The handles might not be present. The size may require two or three handlers to lift. For the most part, however, an amphora was tableware, or sat close to the table, was intended to be seen, and was finely decorated as such by master painters.

Stoppers of perishable materials, which have rarely survived, were used to seal the contents. Two principal types of amphorae existed: the neck amphora, in which the neck and body meet at a sharp angle; and the one-piece amphora, in which the neck and body form a continuous curve. Neck amphorae were commonly used in the early history of ancient Greece, but were gradually replaced by the one-piece type from around the 7th century BC onward.

Most were produced with a pointed base to allow upright storage by embedding in soft ground, such as sand. The base facilitated transport by ship, where the amphorae were packed upright or on their sides in as many as five staggered layers.[1] If upright, the bases probably were held by some sort of rack, and ropes passed through their handles to prevent shifting or toppling during rough seas. Heather and reeds might be used as packing around the vases. Racks could be used in kitchens and shops. The base also concentrated deposits from liquids with suspended solid particles, such as olive oil and wines.

I'd say by the ancient people's idea the pointed base was a feature, not a bug. The smallish size made it easier to handle than a barrel, and it would always be risky to stack fragile clay vessels in large piles without support in any shape. Ships then were smaller and had less cargo volume so huge stacks of barrel-like containers wouldn't fit.

Answer 2

There might be a further explanation, in that leaving a vessel on its side would keep the cork or bung moist. Compare with champagne storage, where the bottles are always laid down to prevent the cork shrinking by drying out.

Answer 3

It is possible that amphora were so shaped to prevent them rolling any distance - the shape would cause them to roll in a tight circle and this would make them safer when transported by sea as they would not upset the weight distribution on the small and fragile vessels of the time. The shape also prevents liquids to surge when tilted for pouring.

Answer 4

Have you ever lifted an anphorae? They are big. They weight quite a lot already when empty. They were not like our plastic bottles. Here are some observations from colleagues that have studied amphorae for nearly their entire life, in Monte Testaccio, a dump from ancient Rome:

1. Amphorae were made for long distance exchanges or storage, so no reason to make them confortable to handle in a daily basis.

2. Observation in common with Ian Bruce which is 100% correct, yet downvoted below:

the shape is engineered to allow a low strength pottery to be able to withstand a considerable weight of contents. That point might function like an inverted arch.

This is because..

3. For ceramic containers the bottom might just fell-off if deformities are present if the container manufacturing or cooking process went wrong.

4. Wide vessel bottoms, in ceramic containers, amount to quite a lot of the total weight of the vessel.

5. The ultimate answer for this question is because the cavitation effect. This is a bubbling effect created when liquid suddenly moves inside a container, creating a brief but strong vacuum that impacts the container botom and does break glass bottles quite easily. Also, similar ceramic containers like amphorae.

Because of this efect, any large bottom vessel will have extra difficulties to withstand a shake. The narrow bottom changes the fluid dynamics and does not allow for the cavitation effect. For further explanation, ask Physics Stack Exchange.

You can see this cavitation effect in many slow motion youtube videos. It does break a beear bottle with just a finger tap, if you know how to tap it.

Answer 5

The point has always baffled me. The idea that it developed so that they could be stored upright in soft sand is often quoted--but seems pretty sketchy. I could speculate that the shape is engineered to allow a low strength pottery to be able to withstand a considerable weight of contents. That point might function like an inverted arch.

Round bottomed pots make sense for a combination of strength (like a dome) and ability to sit comfortably on an earthen floor or in a bed of coals. The pointy bottoms would not work well in that context, as a custom shaped hole would have to be dug. The shape would withstand much heavier loading than a round bottom, however.

Another possibility, is that it is a shape that would be stronger in its weaker, pre-fired stage, which might be important for large heavy, thick walled vessels? Would the shape also facilitate the flow of hot air during firing? I'm sure a lot of research has been done on this--I would love to see it!

Answer 6

For ergonomic pouring. You could hold the amphora with one hand by one of the handles at its neck, while using another hand to steady and lift the base as you tip and pour it out. The stubby point on the bottom of the amphora makes for a nice handgrip.