Little Grey Rabbit's Historical Skepticism Blog

Mauthausen Madness: internal workings of a Topf oven

Posted in Essential Postings, Other Camps by littlegreyrabbit on January 2, 2011

This is a post that I will use both to illustrate the odd behaviour of people who see it as their duty to “defend history” and also to show some rather odd features of the Topf ovens at Mauthausen and the questions it raises about the politicised nature of these memorial sites.

People get all kinds of strange ideas that these was something uniquely brilliant in the design of Topf ovens.  Comments range from “a special oven designed to run on human fat” to JC Pressac’s “a technological little marvel.”  Partly this is to justify the absurdly inflated corpses they were supposed to have processed every hour of every day.  In fact, they were very basic and unsophisticated designs.  In one online discussion I had, a person claiming engineering and physics expertise said that Topf ovens possessed a “gasifier unit” where producer gas was collected and piped off to be combusted in jets beneath the corpse.  To prove his point he circled on the Mauthausen Topf diagram of 1940 where he believed this unit was. 


Mauthausen Topf Blueprint

Lets look further. According to the official narrative the Topf Mauthausen double muffel oven had a very convoluted history.  At the early war crimes trial held at Dachau, a special forcers officer, who had spent around a month at Mauthausen at the very end of the war, gave testimony about his role in constructing it.   Some material about Commander Jack Taylor and his testimony regarding constructing the Topf ovens at Mauthausen can be found here.  It might be a little alarming to consider that one of our main sources regarding the construction of this oven was an employee of the fore-runner of the CIA

JC Pressac gives a summary of the supposed convoluted history of its construction here .   Crucially he claims in summary: “Its metal components were first sent to Auschwitz in August 1942, where there was talk of installing the furnace near Birkenau Bunkers 1 and 2, before they were finally sent on to their correct destination. It would appear that they were left in storage for over a year before the furnace was actually built in July 1944. It did not enter service until April 1945, and even then was used very little, or according to some sources not at all.”  Given the mortality situation was spiralling out of control towards the end of the war, it is not implausible that a decision may have been made to construct these ovens.  However, it is peculiar that the oven had blueprints drawn in 1940, its components delivered in 1942 and only became operational in April 1945 – or according to some witnesses – not at all. 

Here is the oven as it appears today.

Mauthausen Topf Ovens Front

One of my interests is seeing how ovens connected with the flue and the smoke stacks.  According to the blueprint, a flue seems to be located below the oven, at the front, but it is not clear how it connects with the burning chamber.  This arrangement can be found at the genuine site of Auschwitz I, where the flue opening of a missing oven is easily visible.

In this case one can look into major cavity and the ash collection cavity beneath it and clearly see no connection to a flue.   Interestingly, there seems to be no direct connect with the hearth at the back either – the large space shown on the blueprint is missing – if the cremation cavity functioned, it must have been via the vents on the side.   As a check, I opened up the small vent to the left and took a photo inside.

Mauthausen Topf Oven Combustion Gases Vent

Not the best of images, but it shows no connection to a flue and certainly no jets for producer gas to burn out of.  Nor does it seem to be made of heat-protected bricks or shown much sign of carbon deposit.  If this functioned at all, it was simply a conduit for hot combustion gases from the hearth at the back.

Topf Mauthausen Ovens Back View

This is the view of the back of the oven.  It appears to have an opening to put in coal at the top, and an opening at the bottom from which ash might be removed from.   There is also a mysterious small vent on the side, close to the floor (as well as an air input for a forced draft fan – but there is no evidence that such a fan existed).   Lifting the flap of the mysterious small vent and taking a photo revealed this:

Interior of side vent

It is hard to see this vent as having any function at all in regulation air intake for an oven, it looks like nothing more than meaningless decoration

Returning to the rear of the ovens and taking a photograph downwards into the top opening you can see that (if it functioned at all), it was nothing more than a hearth for burning coal.  There is certainly no gasifier unit present. (Although hardly surprisingly the gentleman who first made the gasifier unit claim, refused to concede this and retreated in a flurry of personal abuse.)

View into top opening - the supposed gasifier unit


Below we see the photo taken into the bottom opening.  It seems the upper level could have been the burning hearth – however, one would think that if this bottom door was opening during operation all the burning coal would fall out.  It also doesnt really appear to be carbonised to any degree and in fact, seems a surprising shoddy and hasty construction.

Topf oven - bottom opening - the firing hearth?

Below is a photograph into the same opening – angled downwards.  It appears to be an ash collection area, but it is not clear if there is any grill present for ash to fall through – however, due to the illegal nature of collecting these photos in Austria and the fairly busy traffic at these sites, its difficult to be sure.  Unfortunately, the political situation is such to allow nothing more than a quick, illicit investigation.  Further, in neither area could any feature that might connect to underground flues at the front be seen.

Topf oven - bottom opening- ash collection?


Here is a liberation image of these ovens from USHMM

Post Liberation Photo of Topf Oven



To further investigate the matter of the flues and smokestack, I went outside.  According to the 1940 blueprint, the flues went to the left and out the front of the oven to connect to the smokestack.

Mauthausen crematorium chimney.

The smokestack that would then connect to this Topf oven is the large rectangular structure on the left in the foreground.  It would seem to connect a number of flues together.  It is not possible to inspect the room that it goes down into as the door to it is locked.  See below.

Door to Mauthausen chimney room

There were two other single muffle ovens nearby, one is no longer at the museum site, but the chimney shaft can be seen and place where the oven was installed.  The other is still present and is both suitably begrimed and covered in soot, its flues and smokestack are easy to locate and also equally dirty from use.

Interior of a real Mauthausen oven (not Topf)

Finally a blurry shot of the interior of the chimney (going straight upwards from the right side of the interior of the oven), demonstrating that normally spotting flues for a crematorium should not be an arcane science and that clear signs of ash, deposits etc should be visible.

Interior flue shot of non-Topf oven


It seems to me surprising that a blueprint made in 1940 should so accurately describe what apparently was only constructed in April 1945 (on the testimony of a CIA [OSS] officer).  It would have been a complicated retro-fit of a building, connecting beneath a wall to an already existing chimney smokestack.  Equally, it seems peculiar that it is not possible to fully confirm a connection with flues beneath the floor and to the neighbouring smokestack.  In fact on the face of it, and admitting investigations were by their very nature rather hurried, I would say such flues do not exist.  Moreover this seems to be confirmed by the surprisingly shoddy and flimsy workmanship of the internal parts of the oven at the rear.

In an ideal world it ought to be straightforward to get these suspicions fully investigated.   A man seems to be holding loose the roller rack that is installed at the front of the oven for the stretcher that inserts the bodies.  If you look carefully at the modern photo of the front of the oven above, you can see that this has been (re?)-installed beneath the oven doors.  The amount of ash coming out of the bottom seems to be a little overdone.  This is from the door where the ashes of the deceased are collected.  It appears full to overflowing, suggesting to some extent this photo has been staged.  At this point it is worth remembering that according to JC Pressac some witnesses are supposed to have claimed the oven was not used at all.

2 Responses

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  1. […] are some answered questions about the very moderate single Topf oven existing today ( discussed here and here […]

  2. Question everything said, on August 31, 2012 at 10:20 pm

    Very interesting. Where did you find that blueprint? Are similar blueprints around for Auschwitz? A Vergasungskeller is said to have helped against frost impact. If such a Vergasungskeller is a gas chamber, that won’t do much against frost impact. If it is the gas generator or heater of an oven on the other hand…

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