Wednesday, February 12, 2020

Purchasing a Cook Pot

From a recent conversation to a potential customer :
On 2020-02-09 12:50 PM, D L wrote:
We are looking to acquire Viking cookware such as an Oseberg cauldron or say 7L or so.
from the original excavation report (cooking tools seen to right)
The Oseberg Burial cooking tools, with the pot set on the tripod
I think it goes without saying that because of the popularity of certain recent television programs, there has been a massive increase in items available that brand themselves as 'Viking'(1). Many (if not most) of which have only the vaguest reflection of actual Norse artifacts (not that I might have an opinion here!). For me, the mere use of 'Viking' as the descriptor in advertising (as opposed to either 'Viking Age', or more correctly 'Norse') from a supplier is a clear warning bell. There is also a considerable amount of lower quality gear being now produced in India - and as with all things, you get what you pay for.
I have seen a few options coming from the UK that vary greatly in price and often state that they are not food grade.
We definitely want to cook in them. What do you mean by « oatmeal sealed ». Is this a process that would effectively seam the seams to allow for cooking?
Ok - those pieces of information are important - and I am going to unpack the pieces:

On Viking Age Cookware: 
Interpretation based on Bengstarvet, Sweden, in mild steel.
There are two general materials used for cooking pot construction during the period : Wrought Iron / Copper Alloy

- Actual Wrought Iron is only available as an antique material in the modern world. I have only been able to secure the actual metal  in suitable sheet form * once * in my 40 years of making replicas and reproductions :
- So what everyone is * really * using is modern mild steel sheet. Functionally, it really does not make that much difference on the cooking (or dying) side. Note however, that historic objects are made of far thicker metal than is seen in modern replicas. Thickness on VA pots is closer to 4 - 6 mm. Modern interpretations vary considerably, but most typically will be 1 mm (or less!)
- Many suppliers, however, are pushing * cast * iron objects, which were completely unknown in Europe until about 1600.
- A third related material would be stainless steel
(completely modern / post 1900), Our modern nickle alloy stainless steels which will never take the same colour as forged steel / iron.

'Copper Alloy' in Norse artifact terms is bronze, an alloy of primarily copper, with various other elements added in the mix. (It is this wide variation of elements and proportions that resulted in the shift of description in archaeology, starting in the 1980's) Actual bronze (high copper with tin) is difficult to acquire as sheet (in small quantities, here in Ontario at least). So a common substitute is brass (lower copper with zinc).
I have also made a number of pots (based on the artifact from Mastermyr) out of sheet copper.

Reproduction of the Mastermyr Pot - rendered in sheet copper.

Food Safe ?

So - again we go back to the materials, with implications from the construction methods.
Iron pots in the Viking Age are almost all made of many smaller segments, riveted together. There are two general patterns, either a cylinder with a slightly dished bottom, or a number of curved segments creating a sphere (think of orange segments). These seams are hammered close - but are not water tight.  The method of sealing the seams tight is to cook something especially thick and goopy (oatmeal a common choice)  and let this leak into and burn on to the seams. Then you never clean the outside of the pot.
Technically, this method would not be considered 'food safe' to modern health standards.

Exterior of a wrought iron reproduction pot, showing baked in oatmeal as sealant.
Note that using a forged steel (iron) pot has a tendency to darken the colour of food, this is only cosmetic, not a food safety problem.

It is possible to 'fake' the look of the correct construction by taking a commercial 'spun' pot or form, then hammering in lines (to suggest seams) and lines of tight rivets. This leaves you with an object that would look fine from say about 2 m distance. Also easy to perfectly scour clean the inside. Typically the spinning process requires quite thin metal however.
I have done this in past using stainless steel mixing bowls as the forms - it would represent a low cost alternative.

With copper alloys, both the cylinder and segmented construction have artifact samples. One other construction method is to 'finger overlap' seam edges (used in the Mastermyr sample seen above). Copper alloys can be soldered water tight.
- The potential problem with high copper alloys is that the green oxide formed (if allowed to sit for a long time without cleaning!) is poisonous. One possible solution to this is to 'tin' the interior surface. This method is seen in much later time periods, but little evidence is found on actual VA artifacts. Easy solution here is just to * clean your gear * after use!
- This all raises the most common problem with modern 'replicas', most especially those cheap end versions from the Middle East or India. Use of lead based solders, the lead being quite toxic! 

I would strongly recommend NOT cooking in any soldered seam pot that does not  specifically  list the use of modern 'lead free' (tin) solders.

I can report that DARC has used actual wrought iron and mild steel pots with oatmeal sealing, copper / brass pots with lead free solder joints - all for decades now in regular presentations. On a number of occasions for as long as two week periods. Never with a problem with food safety.

As to the thickness, I would have to default to your expertise.
Generally, modern industry is able to create much thinner sheets than available during the Viking Age. Although heavier sheet is available, it requires considerably more work effort to form (and big cost increases as raw materials - especially with high copper alloys).
The balance here is controlling cooking process over an open fire. Generally the thicker walls mean more even cooking. This is especially a problem with the thin stainless spun bowls I mention above. These work great for 'wet' cooking (like soups), but make it hard to control burning the bottom with thick stuff like stews.
I have a good supply of 1/8 thick mild steel (so 3 mm) sheet, if looking at one of the segmented iron types.
Note that copper is considerably more expensive as a raw material.
I currently have a full sheet of actual sheet bronze of suitable thickness (about 1.5 mm) on hand (chance find!)

As for an exact replicas, we are not an actual museum but we aspire to learn, to share and to be become as close to historical as we can given our means.
There are some general outlines on costing on the 'Norse Replicas' part of the Wareham Forge web site. Any specific object needs to be quoted individually.  As you can see there are a lot of variables depending on details.

Oh - one other thing. I've replicated the Oseberg Tripod a number of times - and much as I would like to sell anyone reading a reproduction :
This is an extremely problematic object - and most likely was NEVER an actual cooking tool.
The most accurate would be a simple wood pole tripod!  

Oseberg Tripod - My Interpretation
Tripods in the Viking Age - again

Norse cookware created for the feature film Outlander, in 2006. Also included a cauldron hanger and cauldron, and a 'slave chain'. The chain and the cauldron set are both clearly seen in the final film.

All the replicas seen here : by the Wareham Forge
 1) On a three minute search on the internet found a typical example : 'Viking Shield
- You will see on the 'about us' that there is absolutely no information what so ever about sources of the objects offered. 'In Business since 2000' does not inform you in any way what so ever about research, accuracy, materials, ...
Check the offerings listed as 'Feasting'. NOT ONE of those objects is based on ANY known Viking Age artifacts. Description of materials is in fact INCORRECT
Fantasy designs, poor descriptions, lack of quality - and yes, cheap pricing = objects bulk purchased from India. 
Hot Links deliberately avoided. 

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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